OpenCores
URL https://opencores.org/ocsvn/or1k_soc_on_altera_embedded_dev_kit/or1k_soc_on_altera_embedded_dev_kit/trunk

Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

[/] [or1k_soc_on_altera_embedded_dev_kit/] [trunk/] [linux-2.6/] [linux-2.6.24/] [mm/] [memory.c] - Blame information for rev 11

Go to most recent revision | Details | Compare with Previous | View Log

Line No. Rev Author Line
1 3 xianfeng
/*
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/delayacct.h>
51
#include <linux/init.h>
52
#include <linux/writeback.h>
53
 
54
#include <asm/pgalloc.h>
55
#include <asm/uaccess.h>
56
#include <asm/tlb.h>
57
#include <asm/tlbflush.h>
58
#include <asm/pgtable.h>
59
 
60
#include <linux/swapops.h>
61
#include <linux/elf.h>
62
 
63
#ifndef CONFIG_NEED_MULTIPLE_NODES
64
/* use the per-pgdat data instead for discontigmem - mbligh */
65
unsigned long max_mapnr;
66
struct page *mem_map;
67
 
68
EXPORT_SYMBOL(max_mapnr);
69
EXPORT_SYMBOL(mem_map);
70
#endif
71
 
72
unsigned long num_physpages;
73
/*
74
 * A number of key systems in x86 including ioremap() rely on the assumption
75
 * that high_memory defines the upper bound on direct map memory, then end
76
 * of ZONE_NORMAL.  Under CONFIG_DISCONTIG this means that max_low_pfn and
77
 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
78
 * and ZONE_HIGHMEM.
79
 */
80
void * high_memory;
81
 
82
EXPORT_SYMBOL(num_physpages);
83
EXPORT_SYMBOL(high_memory);
84
 
85
int randomize_va_space __read_mostly = 1;
86
 
87
static int __init disable_randmaps(char *s)
88
{
89
        randomize_va_space = 0;
90
        return 1;
91
}
92
__setup("norandmaps", disable_randmaps);
93
 
94
 
95
/*
96
 * If a p?d_bad entry is found while walking page tables, report
97
 * the error, before resetting entry to p?d_none.  Usually (but
98
 * very seldom) called out from the p?d_none_or_clear_bad macros.
99
 */
100
 
101
void pgd_clear_bad(pgd_t *pgd)
102
{
103
        pgd_ERROR(*pgd);
104
        pgd_clear(pgd);
105
}
106
 
107
void pud_clear_bad(pud_t *pud)
108
{
109
        pud_ERROR(*pud);
110
        pud_clear(pud);
111
}
112
 
113
void pmd_clear_bad(pmd_t *pmd)
114
{
115
        pmd_ERROR(*pmd);
116
        pmd_clear(pmd);
117
}
118
 
119
/*
120
 * Note: this doesn't free the actual pages themselves. That
121
 * has been handled earlier when unmapping all the memory regions.
122
 */
123
static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
124
{
125
        struct page *page = pmd_page(*pmd);
126
        pmd_clear(pmd);
127
        pte_lock_deinit(page);
128
        pte_free_tlb(tlb, page);
129
        dec_zone_page_state(page, NR_PAGETABLE);
130
        tlb->mm->nr_ptes--;
131
}
132
 
133
static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
134
                                unsigned long addr, unsigned long end,
135
                                unsigned long floor, unsigned long ceiling)
136
{
137
        pmd_t *pmd;
138
        unsigned long next;
139
        unsigned long start;
140
 
141
        start = addr;
142
        pmd = pmd_offset(pud, addr);
143
        do {
144
                next = pmd_addr_end(addr, end);
145
                if (pmd_none_or_clear_bad(pmd))
146
                        continue;
147
                free_pte_range(tlb, pmd);
148
        } while (pmd++, addr = next, addr != end);
149
 
150
        start &= PUD_MASK;
151
        if (start < floor)
152
                return;
153
        if (ceiling) {
154
                ceiling &= PUD_MASK;
155
                if (!ceiling)
156
                        return;
157
        }
158
        if (end - 1 > ceiling - 1)
159
                return;
160
 
161
        pmd = pmd_offset(pud, start);
162
        pud_clear(pud);
163
        pmd_free_tlb(tlb, pmd);
164
}
165
 
166
static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
167
                                unsigned long addr, unsigned long end,
168
                                unsigned long floor, unsigned long ceiling)
169
{
170
        pud_t *pud;
171
        unsigned long next;
172
        unsigned long start;
173
 
174
        start = addr;
175
        pud = pud_offset(pgd, addr);
176
        do {
177
                next = pud_addr_end(addr, end);
178
                if (pud_none_or_clear_bad(pud))
179
                        continue;
180
                free_pmd_range(tlb, pud, addr, next, floor, ceiling);
181
        } while (pud++, addr = next, addr != end);
182
 
183
        start &= PGDIR_MASK;
184
        if (start < floor)
185
                return;
186
        if (ceiling) {
187
                ceiling &= PGDIR_MASK;
188
                if (!ceiling)
189
                        return;
190
        }
191
        if (end - 1 > ceiling - 1)
192
                return;
193
 
194
        pud = pud_offset(pgd, start);
195
        pgd_clear(pgd);
196
        pud_free_tlb(tlb, pud);
197
}
198
 
199
/*
200
 * This function frees user-level page tables of a process.
201
 *
202
 * Must be called with pagetable lock held.
203
 */
204
void free_pgd_range(struct mmu_gather **tlb,
205
                        unsigned long addr, unsigned long end,
206
                        unsigned long floor, unsigned long ceiling)
207
{
208
        pgd_t *pgd;
209
        unsigned long next;
210
        unsigned long start;
211
 
212
        /*
213
         * The next few lines have given us lots of grief...
214
         *
215
         * Why are we testing PMD* at this top level?  Because often
216
         * there will be no work to do at all, and we'd prefer not to
217
         * go all the way down to the bottom just to discover that.
218
         *
219
         * Why all these "- 1"s?  Because 0 represents both the bottom
220
         * of the address space and the top of it (using -1 for the
221
         * top wouldn't help much: the masks would do the wrong thing).
222
         * The rule is that addr 0 and floor 0 refer to the bottom of
223
         * the address space, but end 0 and ceiling 0 refer to the top
224
         * Comparisons need to use "end - 1" and "ceiling - 1" (though
225
         * that end 0 case should be mythical).
226
         *
227
         * Wherever addr is brought up or ceiling brought down, we must
228
         * be careful to reject "the opposite 0" before it confuses the
229
         * subsequent tests.  But what about where end is brought down
230
         * by PMD_SIZE below? no, end can't go down to 0 there.
231
         *
232
         * Whereas we round start (addr) and ceiling down, by different
233
         * masks at different levels, in order to test whether a table
234
         * now has no other vmas using it, so can be freed, we don't
235
         * bother to round floor or end up - the tests don't need that.
236
         */
237
 
238
        addr &= PMD_MASK;
239
        if (addr < floor) {
240
                addr += PMD_SIZE;
241
                if (!addr)
242
                        return;
243
        }
244
        if (ceiling) {
245
                ceiling &= PMD_MASK;
246
                if (!ceiling)
247
                        return;
248
        }
249
        if (end - 1 > ceiling - 1)
250
                end -= PMD_SIZE;
251
        if (addr > end - 1)
252
                return;
253
 
254
        start = addr;
255
        pgd = pgd_offset((*tlb)->mm, addr);
256
        do {
257
                next = pgd_addr_end(addr, end);
258
                if (pgd_none_or_clear_bad(pgd))
259
                        continue;
260
                free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
261
        } while (pgd++, addr = next, addr != end);
262
}
263
 
264
void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
265
                unsigned long floor, unsigned long ceiling)
266
{
267
        while (vma) {
268
                struct vm_area_struct *next = vma->vm_next;
269
                unsigned long addr = vma->vm_start;
270
 
271
                /*
272
                 * Hide vma from rmap and vmtruncate before freeing pgtables
273
                 */
274
                anon_vma_unlink(vma);
275
                unlink_file_vma(vma);
276
 
277
                if (is_vm_hugetlb_page(vma)) {
278
                        hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
279
                                floor, next? next->vm_start: ceiling);
280
                } else {
281
                        /*
282
                         * Optimization: gather nearby vmas into one call down
283
                         */
284
                        while (next && next->vm_start <= vma->vm_end + PMD_SIZE
285
                               && !is_vm_hugetlb_page(next)) {
286
                                vma = next;
287
                                next = vma->vm_next;
288
                                anon_vma_unlink(vma);
289
                                unlink_file_vma(vma);
290
                        }
291
                        free_pgd_range(tlb, addr, vma->vm_end,
292
                                floor, next? next->vm_start: ceiling);
293
                }
294
                vma = next;
295
        }
296
}
297
 
298
int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
299
{
300
        struct page *new = pte_alloc_one(mm, address);
301
        if (!new)
302
                return -ENOMEM;
303
 
304
        pte_lock_init(new);
305
        spin_lock(&mm->page_table_lock);
306
        if (pmd_present(*pmd)) {        /* Another has populated it */
307
                pte_lock_deinit(new);
308
                pte_free(new);
309
        } else {
310
                mm->nr_ptes++;
311
                inc_zone_page_state(new, NR_PAGETABLE);
312
                pmd_populate(mm, pmd, new);
313
        }
314
        spin_unlock(&mm->page_table_lock);
315
        return 0;
316
}
317
 
318
int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
319
{
320
        pte_t *new = pte_alloc_one_kernel(&init_mm, address);
321
        if (!new)
322
                return -ENOMEM;
323
 
324
        spin_lock(&init_mm.page_table_lock);
325
        if (pmd_present(*pmd))          /* Another has populated it */
326
                pte_free_kernel(new);
327
        else
328
                pmd_populate_kernel(&init_mm, pmd, new);
329
        spin_unlock(&init_mm.page_table_lock);
330
        return 0;
331
}
332
 
333
static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
334
{
335
        if (file_rss)
336
                add_mm_counter(mm, file_rss, file_rss);
337
        if (anon_rss)
338
                add_mm_counter(mm, anon_rss, anon_rss);
339
}
340
 
341
/*
342
 * This function is called to print an error when a bad pte
343
 * is found. For example, we might have a PFN-mapped pte in
344
 * a region that doesn't allow it.
345
 *
346
 * The calling function must still handle the error.
347
 */
348
void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
349
{
350
        printk(KERN_ERR "Bad pte = %08llx, process = %s, "
351
                        "vm_flags = %lx, vaddr = %lx\n",
352
                (long long)pte_val(pte),
353
                (vma->vm_mm == current->mm ? current->comm : "???"),
354
                vma->vm_flags, vaddr);
355
        dump_stack();
356
}
357
 
358
static inline int is_cow_mapping(unsigned int flags)
359
{
360
        return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
361
}
362
 
363
/*
364
 * This function gets the "struct page" associated with a pte.
365
 *
366
 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
367
 * will have each page table entry just pointing to a raw page frame
368
 * number, and as far as the VM layer is concerned, those do not have
369
 * pages associated with them - even if the PFN might point to memory
370
 * that otherwise is perfectly fine and has a "struct page".
371
 *
372
 * The way we recognize those mappings is through the rules set up
373
 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
374
 * and the vm_pgoff will point to the first PFN mapped: thus every
375
 * page that is a raw mapping will always honor the rule
376
 *
377
 *      pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
378
 *
379
 * and if that isn't true, the page has been COW'ed (in which case it
380
 * _does_ have a "struct page" associated with it even if it is in a
381
 * VM_PFNMAP range).
382
 */
383
struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
384
{
385
        unsigned long pfn = pte_pfn(pte);
386
 
387
        if (unlikely(vma->vm_flags & VM_PFNMAP)) {
388
                unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
389
                if (pfn == vma->vm_pgoff + off)
390
                        return NULL;
391
                if (!is_cow_mapping(vma->vm_flags))
392
                        return NULL;
393
        }
394
 
395
#ifdef CONFIG_DEBUG_VM
396
        /*
397
         * Add some anal sanity checks for now. Eventually,
398
         * we should just do "return pfn_to_page(pfn)", but
399
         * in the meantime we check that we get a valid pfn,
400
         * and that the resulting page looks ok.
401
         */
402
        if (unlikely(!pfn_valid(pfn))) {
403
                print_bad_pte(vma, pte, addr);
404
                return NULL;
405
        }
406
#endif
407
 
408
        /*
409
         * NOTE! We still have PageReserved() pages in the page
410
         * tables.
411
         *
412
         * The PAGE_ZERO() pages and various VDSO mappings can
413
         * cause them to exist.
414
         */
415
        return pfn_to_page(pfn);
416
}
417
 
418
/*
419
 * copy one vm_area from one task to the other. Assumes the page tables
420
 * already present in the new task to be cleared in the whole range
421
 * covered by this vma.
422
 */
423
 
424
static inline void
425
copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
426
                pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
427
                unsigned long addr, int *rss)
428
{
429
        unsigned long vm_flags = vma->vm_flags;
430
        pte_t pte = *src_pte;
431
        struct page *page;
432
 
433
        /* pte contains position in swap or file, so copy. */
434
        if (unlikely(!pte_present(pte))) {
435
                if (!pte_file(pte)) {
436
                        swp_entry_t entry = pte_to_swp_entry(pte);
437
 
438
                        swap_duplicate(entry);
439
                        /* make sure dst_mm is on swapoff's mmlist. */
440
                        if (unlikely(list_empty(&dst_mm->mmlist))) {
441
                                spin_lock(&mmlist_lock);
442
                                if (list_empty(&dst_mm->mmlist))
443
                                        list_add(&dst_mm->mmlist,
444
                                                 &src_mm->mmlist);
445
                                spin_unlock(&mmlist_lock);
446
                        }
447
                        if (is_write_migration_entry(entry) &&
448
                                        is_cow_mapping(vm_flags)) {
449
                                /*
450
                                 * COW mappings require pages in both parent
451
                                 * and child to be set to read.
452
                                 */
453
                                make_migration_entry_read(&entry);
454
                                pte = swp_entry_to_pte(entry);
455
                                set_pte_at(src_mm, addr, src_pte, pte);
456
                        }
457
                }
458
                goto out_set_pte;
459
        }
460
 
461
        /*
462
         * If it's a COW mapping, write protect it both
463
         * in the parent and the child
464
         */
465
        if (is_cow_mapping(vm_flags)) {
466
                ptep_set_wrprotect(src_mm, addr, src_pte);
467
                pte = pte_wrprotect(pte);
468
        }
469
 
470
        /*
471
         * If it's a shared mapping, mark it clean in
472
         * the child
473
         */
474
        if (vm_flags & VM_SHARED)
475
                pte = pte_mkclean(pte);
476
        pte = pte_mkold(pte);
477
 
478
        page = vm_normal_page(vma, addr, pte);
479
        if (page) {
480
                get_page(page);
481
                page_dup_rmap(page, vma, addr);
482
                rss[!!PageAnon(page)]++;
483
        }
484
 
485
out_set_pte:
486
        set_pte_at(dst_mm, addr, dst_pte, pte);
487
}
488
 
489
static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
490
                pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
491
                unsigned long addr, unsigned long end)
492
{
493
        pte_t *src_pte, *dst_pte;
494
        spinlock_t *src_ptl, *dst_ptl;
495
        int progress = 0;
496
        int rss[2];
497
 
498
again:
499
        rss[1] = rss[0] = 0;
500
        dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
501
        if (!dst_pte)
502
                return -ENOMEM;
503
        src_pte = pte_offset_map_nested(src_pmd, addr);
504
        src_ptl = pte_lockptr(src_mm, src_pmd);
505
        spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
506
        arch_enter_lazy_mmu_mode();
507
 
508
        do {
509
                /*
510
                 * We are holding two locks at this point - either of them
511
                 * could generate latencies in another task on another CPU.
512
                 */
513
                if (progress >= 32) {
514
                        progress = 0;
515
                        if (need_resched() ||
516
                            need_lockbreak(src_ptl) ||
517
                            need_lockbreak(dst_ptl))
518
                                break;
519
                }
520
                if (pte_none(*src_pte)) {
521
                        progress++;
522
                        continue;
523
                }
524
                copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
525
                progress += 8;
526
        } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
527
 
528
        arch_leave_lazy_mmu_mode();
529
        spin_unlock(src_ptl);
530
        pte_unmap_nested(src_pte - 1);
531
        add_mm_rss(dst_mm, rss[0], rss[1]);
532
        pte_unmap_unlock(dst_pte - 1, dst_ptl);
533
        cond_resched();
534
        if (addr != end)
535
                goto again;
536
        return 0;
537
}
538
 
539
static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
540
                pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
541
                unsigned long addr, unsigned long end)
542
{
543
        pmd_t *src_pmd, *dst_pmd;
544
        unsigned long next;
545
 
546
        dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
547
        if (!dst_pmd)
548
                return -ENOMEM;
549
        src_pmd = pmd_offset(src_pud, addr);
550
        do {
551
                next = pmd_addr_end(addr, end);
552
                if (pmd_none_or_clear_bad(src_pmd))
553
                        continue;
554
                if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
555
                                                vma, addr, next))
556
                        return -ENOMEM;
557
        } while (dst_pmd++, src_pmd++, addr = next, addr != end);
558
        return 0;
559
}
560
 
561
static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
562
                pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
563
                unsigned long addr, unsigned long end)
564
{
565
        pud_t *src_pud, *dst_pud;
566
        unsigned long next;
567
 
568
        dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
569
        if (!dst_pud)
570
                return -ENOMEM;
571
        src_pud = pud_offset(src_pgd, addr);
572
        do {
573
                next = pud_addr_end(addr, end);
574
                if (pud_none_or_clear_bad(src_pud))
575
                        continue;
576
                if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
577
                                                vma, addr, next))
578
                        return -ENOMEM;
579
        } while (dst_pud++, src_pud++, addr = next, addr != end);
580
        return 0;
581
}
582
 
583
int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
584
                struct vm_area_struct *vma)
585
{
586
        pgd_t *src_pgd, *dst_pgd;
587
        unsigned long next;
588
        unsigned long addr = vma->vm_start;
589
        unsigned long end = vma->vm_end;
590
 
591
        /*
592
         * Don't copy ptes where a page fault will fill them correctly.
593
         * Fork becomes much lighter when there are big shared or private
594
         * readonly mappings. The tradeoff is that copy_page_range is more
595
         * efficient than faulting.
596
         */
597
        if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
598
                if (!vma->anon_vma)
599
                        return 0;
600
        }
601
 
602
        if (is_vm_hugetlb_page(vma))
603
                return copy_hugetlb_page_range(dst_mm, src_mm, vma);
604
 
605
        dst_pgd = pgd_offset(dst_mm, addr);
606
        src_pgd = pgd_offset(src_mm, addr);
607
        do {
608
                next = pgd_addr_end(addr, end);
609
                if (pgd_none_or_clear_bad(src_pgd))
610
                        continue;
611
                if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
612
                                                vma, addr, next))
613
                        return -ENOMEM;
614
        } while (dst_pgd++, src_pgd++, addr = next, addr != end);
615
        return 0;
616
}
617
 
618
static unsigned long zap_pte_range(struct mmu_gather *tlb,
619
                                struct vm_area_struct *vma, pmd_t *pmd,
620
                                unsigned long addr, unsigned long end,
621
                                long *zap_work, struct zap_details *details)
622
{
623
        struct mm_struct *mm = tlb->mm;
624
        pte_t *pte;
625
        spinlock_t *ptl;
626
        int file_rss = 0;
627
        int anon_rss = 0;
628
 
629
        pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
630
        arch_enter_lazy_mmu_mode();
631
        do {
632
                pte_t ptent = *pte;
633
                if (pte_none(ptent)) {
634
                        (*zap_work)--;
635
                        continue;
636
                }
637
 
638
                (*zap_work) -= PAGE_SIZE;
639
 
640
                if (pte_present(ptent)) {
641
                        struct page *page;
642
 
643
                        page = vm_normal_page(vma, addr, ptent);
644
                        if (unlikely(details) && page) {
645
                                /*
646
                                 * unmap_shared_mapping_pages() wants to
647
                                 * invalidate cache without truncating:
648
                                 * unmap shared but keep private pages.
649
                                 */
650
                                if (details->check_mapping &&
651
                                    details->check_mapping != page->mapping)
652
                                        continue;
653
                                /*
654
                                 * Each page->index must be checked when
655
                                 * invalidating or truncating nonlinear.
656
                                 */
657
                                if (details->nonlinear_vma &&
658
                                    (page->index < details->first_index ||
659
                                     page->index > details->last_index))
660
                                        continue;
661
                        }
662
                        ptent = ptep_get_and_clear_full(mm, addr, pte,
663
                                                        tlb->fullmm);
664
                        tlb_remove_tlb_entry(tlb, pte, addr);
665
                        if (unlikely(!page))
666
                                continue;
667
                        if (unlikely(details) && details->nonlinear_vma
668
                            && linear_page_index(details->nonlinear_vma,
669
                                                addr) != page->index)
670
                                set_pte_at(mm, addr, pte,
671
                                           pgoff_to_pte(page->index));
672
                        if (PageAnon(page))
673
                                anon_rss--;
674
                        else {
675
                                if (pte_dirty(ptent))
676
                                        set_page_dirty(page);
677
                                if (pte_young(ptent))
678
                                        SetPageReferenced(page);
679
                                file_rss--;
680
                        }
681
                        page_remove_rmap(page, vma);
682
                        tlb_remove_page(tlb, page);
683
                        continue;
684
                }
685
                /*
686
                 * If details->check_mapping, we leave swap entries;
687
                 * if details->nonlinear_vma, we leave file entries.
688
                 */
689
                if (unlikely(details))
690
                        continue;
691
                if (!pte_file(ptent))
692
                        free_swap_and_cache(pte_to_swp_entry(ptent));
693
                pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
694
        } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
695
 
696
        add_mm_rss(mm, file_rss, anon_rss);
697
        arch_leave_lazy_mmu_mode();
698
        pte_unmap_unlock(pte - 1, ptl);
699
 
700
        return addr;
701
}
702
 
703
static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
704
                                struct vm_area_struct *vma, pud_t *pud,
705
                                unsigned long addr, unsigned long end,
706
                                long *zap_work, struct zap_details *details)
707
{
708
        pmd_t *pmd;
709
        unsigned long next;
710
 
711
        pmd = pmd_offset(pud, addr);
712
        do {
713
                next = pmd_addr_end(addr, end);
714
                if (pmd_none_or_clear_bad(pmd)) {
715
                        (*zap_work)--;
716
                        continue;
717
                }
718
                next = zap_pte_range(tlb, vma, pmd, addr, next,
719
                                                zap_work, details);
720
        } while (pmd++, addr = next, (addr != end && *zap_work > 0));
721
 
722
        return addr;
723
}
724
 
725
static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
726
                                struct vm_area_struct *vma, pgd_t *pgd,
727
                                unsigned long addr, unsigned long end,
728
                                long *zap_work, struct zap_details *details)
729
{
730
        pud_t *pud;
731
        unsigned long next;
732
 
733
        pud = pud_offset(pgd, addr);
734
        do {
735
                next = pud_addr_end(addr, end);
736
                if (pud_none_or_clear_bad(pud)) {
737
                        (*zap_work)--;
738
                        continue;
739
                }
740
                next = zap_pmd_range(tlb, vma, pud, addr, next,
741
                                                zap_work, details);
742
        } while (pud++, addr = next, (addr != end && *zap_work > 0));
743
 
744
        return addr;
745
}
746
 
747
static unsigned long unmap_page_range(struct mmu_gather *tlb,
748
                                struct vm_area_struct *vma,
749
                                unsigned long addr, unsigned long end,
750
                                long *zap_work, struct zap_details *details)
751
{
752
        pgd_t *pgd;
753
        unsigned long next;
754
 
755
        if (details && !details->check_mapping && !details->nonlinear_vma)
756
                details = NULL;
757
 
758
        BUG_ON(addr >= end);
759
        tlb_start_vma(tlb, vma);
760
        pgd = pgd_offset(vma->vm_mm, addr);
761
        do {
762
                next = pgd_addr_end(addr, end);
763
                if (pgd_none_or_clear_bad(pgd)) {
764
                        (*zap_work)--;
765
                        continue;
766
                }
767
                next = zap_pud_range(tlb, vma, pgd, addr, next,
768
                                                zap_work, details);
769
        } while (pgd++, addr = next, (addr != end && *zap_work > 0));
770
        tlb_end_vma(tlb, vma);
771
 
772
        return addr;
773
}
774
 
775
#ifdef CONFIG_PREEMPT
776
# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
777
#else
778
/* No preempt: go for improved straight-line efficiency */
779
# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
780
#endif
781
 
782
/**
783
 * unmap_vmas - unmap a range of memory covered by a list of vma's
784
 * @tlbp: address of the caller's struct mmu_gather
785
 * @vma: the starting vma
786
 * @start_addr: virtual address at which to start unmapping
787
 * @end_addr: virtual address at which to end unmapping
788
 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
789
 * @details: details of nonlinear truncation or shared cache invalidation
790
 *
791
 * Returns the end address of the unmapping (restart addr if interrupted).
792
 *
793
 * Unmap all pages in the vma list.
794
 *
795
 * We aim to not hold locks for too long (for scheduling latency reasons).
796
 * So zap pages in ZAP_BLOCK_SIZE bytecounts.  This means we need to
797
 * return the ending mmu_gather to the caller.
798
 *
799
 * Only addresses between `start' and `end' will be unmapped.
800
 *
801
 * The VMA list must be sorted in ascending virtual address order.
802
 *
803
 * unmap_vmas() assumes that the caller will flush the whole unmapped address
804
 * range after unmap_vmas() returns.  So the only responsibility here is to
805
 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
806
 * drops the lock and schedules.
807
 */
808
unsigned long unmap_vmas(struct mmu_gather **tlbp,
809
                struct vm_area_struct *vma, unsigned long start_addr,
810
                unsigned long end_addr, unsigned long *nr_accounted,
811
                struct zap_details *details)
812
{
813
        long zap_work = ZAP_BLOCK_SIZE;
814
        unsigned long tlb_start = 0;     /* For tlb_finish_mmu */
815
        int tlb_start_valid = 0;
816
        unsigned long start = start_addr;
817
        spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
818
        int fullmm = (*tlbp)->fullmm;
819
 
820
        for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
821
                unsigned long end;
822
 
823
                start = max(vma->vm_start, start_addr);
824
                if (start >= vma->vm_end)
825
                        continue;
826
                end = min(vma->vm_end, end_addr);
827
                if (end <= vma->vm_start)
828
                        continue;
829
 
830
                if (vma->vm_flags & VM_ACCOUNT)
831
                        *nr_accounted += (end - start) >> PAGE_SHIFT;
832
 
833
                while (start != end) {
834
                        if (!tlb_start_valid) {
835
                                tlb_start = start;
836
                                tlb_start_valid = 1;
837
                        }
838
 
839
                        if (unlikely(is_vm_hugetlb_page(vma))) {
840
                                unmap_hugepage_range(vma, start, end);
841
                                zap_work -= (end - start) /
842
                                                (HPAGE_SIZE / PAGE_SIZE);
843
                                start = end;
844
                        } else
845
                                start = unmap_page_range(*tlbp, vma,
846
                                                start, end, &zap_work, details);
847
 
848
                        if (zap_work > 0) {
849
                                BUG_ON(start != end);
850
                                break;
851
                        }
852
 
853
                        tlb_finish_mmu(*tlbp, tlb_start, start);
854
 
855
                        if (need_resched() ||
856
                                (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
857
                                if (i_mmap_lock) {
858
                                        *tlbp = NULL;
859
                                        goto out;
860
                                }
861
                                cond_resched();
862
                        }
863
 
864
                        *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
865
                        tlb_start_valid = 0;
866
                        zap_work = ZAP_BLOCK_SIZE;
867
                }
868
        }
869
out:
870
        return start;   /* which is now the end (or restart) address */
871
}
872
 
873
/**
874
 * zap_page_range - remove user pages in a given range
875
 * @vma: vm_area_struct holding the applicable pages
876
 * @address: starting address of pages to zap
877
 * @size: number of bytes to zap
878
 * @details: details of nonlinear truncation or shared cache invalidation
879
 */
880
unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
881
                unsigned long size, struct zap_details *details)
882
{
883
        struct mm_struct *mm = vma->vm_mm;
884
        struct mmu_gather *tlb;
885
        unsigned long end = address + size;
886
        unsigned long nr_accounted = 0;
887
 
888
        lru_add_drain();
889
        tlb = tlb_gather_mmu(mm, 0);
890
        update_hiwater_rss(mm);
891
        end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
892
        if (tlb)
893
                tlb_finish_mmu(tlb, address, end);
894
        return end;
895
}
896
 
897
/*
898
 * Do a quick page-table lookup for a single page.
899
 */
900
struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
901
                        unsigned int flags)
902
{
903
        pgd_t *pgd;
904
        pud_t *pud;
905
        pmd_t *pmd;
906
        pte_t *ptep, pte;
907
        spinlock_t *ptl;
908
        struct page *page;
909
        struct mm_struct *mm = vma->vm_mm;
910
 
911
        page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
912
        if (!IS_ERR(page)) {
913
                BUG_ON(flags & FOLL_GET);
914
                goto out;
915
        }
916
 
917
        page = NULL;
918
        pgd = pgd_offset(mm, address);
919
        if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
920
                goto no_page_table;
921
 
922
        pud = pud_offset(pgd, address);
923
        if (pud_none(*pud) || unlikely(pud_bad(*pud)))
924
                goto no_page_table;
925
 
926
        pmd = pmd_offset(pud, address);
927
        if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
928
                goto no_page_table;
929
 
930
        if (pmd_huge(*pmd)) {
931
                BUG_ON(flags & FOLL_GET);
932
                page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
933
                goto out;
934
        }
935
 
936
        ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
937
        if (!ptep)
938
                goto out;
939
 
940
        pte = *ptep;
941
        if (!pte_present(pte))
942
                goto unlock;
943
        if ((flags & FOLL_WRITE) && !pte_write(pte))
944
                goto unlock;
945
        page = vm_normal_page(vma, address, pte);
946
        if (unlikely(!page))
947
                goto unlock;
948
 
949
        if (flags & FOLL_GET)
950
                get_page(page);
951
        if (flags & FOLL_TOUCH) {
952
                if ((flags & FOLL_WRITE) &&
953
                    !pte_dirty(pte) && !PageDirty(page))
954
                        set_page_dirty(page);
955
                mark_page_accessed(page);
956
        }
957
unlock:
958
        pte_unmap_unlock(ptep, ptl);
959
out:
960
        return page;
961
 
962
no_page_table:
963
        /*
964
         * When core dumping an enormous anonymous area that nobody
965
         * has touched so far, we don't want to allocate page tables.
966
         */
967
        if (flags & FOLL_ANON) {
968
                page = ZERO_PAGE(0);
969
                if (flags & FOLL_GET)
970
                        get_page(page);
971
                BUG_ON(flags & FOLL_WRITE);
972
        }
973
        return page;
974
}
975
 
976
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
977
                unsigned long start, int len, int write, int force,
978
                struct page **pages, struct vm_area_struct **vmas)
979
{
980
        int i;
981
        unsigned int vm_flags;
982
 
983
        /*
984
         * Require read or write permissions.
985
         * If 'force' is set, we only require the "MAY" flags.
986
         */
987
        vm_flags  = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
988
        vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
989
        i = 0;
990
 
991
        do {
992
                struct vm_area_struct *vma;
993
                unsigned int foll_flags;
994
 
995
                vma = find_extend_vma(mm, start);
996
                if (!vma && in_gate_area(tsk, start)) {
997
                        unsigned long pg = start & PAGE_MASK;
998
                        struct vm_area_struct *gate_vma = get_gate_vma(tsk);
999
                        pgd_t *pgd;
1000
                        pud_t *pud;
1001
                        pmd_t *pmd;
1002
                        pte_t *pte;
1003
                        if (write) /* user gate pages are read-only */
1004
                                return i ? : -EFAULT;
1005
                        if (pg > TASK_SIZE)
1006
                                pgd = pgd_offset_k(pg);
1007
                        else
1008
                                pgd = pgd_offset_gate(mm, pg);
1009
                        BUG_ON(pgd_none(*pgd));
1010
                        pud = pud_offset(pgd, pg);
1011
                        BUG_ON(pud_none(*pud));
1012
                        pmd = pmd_offset(pud, pg);
1013
                        if (pmd_none(*pmd))
1014
                                return i ? : -EFAULT;
1015
                        pte = pte_offset_map(pmd, pg);
1016
                        if (pte_none(*pte)) {
1017
                                pte_unmap(pte);
1018
                                return i ? : -EFAULT;
1019
                        }
1020
                        if (pages) {
1021
                                struct page *page = vm_normal_page(gate_vma, start, *pte);
1022
                                pages[i] = page;
1023
                                if (page)
1024
                                        get_page(page);
1025
                        }
1026
                        pte_unmap(pte);
1027
                        if (vmas)
1028
                                vmas[i] = gate_vma;
1029
                        i++;
1030
                        start += PAGE_SIZE;
1031
                        len--;
1032
                        continue;
1033
                }
1034
 
1035
                if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
1036
                                || !(vm_flags & vma->vm_flags))
1037
                        return i ? : -EFAULT;
1038
 
1039
                if (is_vm_hugetlb_page(vma)) {
1040
                        i = follow_hugetlb_page(mm, vma, pages, vmas,
1041
                                                &start, &len, i, write);
1042
                        continue;
1043
                }
1044
 
1045
                foll_flags = FOLL_TOUCH;
1046
                if (pages)
1047
                        foll_flags |= FOLL_GET;
1048
                if (!write && !(vma->vm_flags & VM_LOCKED) &&
1049
                    (!vma->vm_ops || (!vma->vm_ops->nopage &&
1050
                                        !vma->vm_ops->fault)))
1051
                        foll_flags |= FOLL_ANON;
1052
 
1053
                do {
1054
                        struct page *page;
1055
 
1056
                        /*
1057
                         * If tsk is ooming, cut off its access to large memory
1058
                         * allocations. It has a pending SIGKILL, but it can't
1059
                         * be processed until returning to user space.
1060
                         */
1061
                        if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
1062
                                return -ENOMEM;
1063
 
1064
                        if (write)
1065
                                foll_flags |= FOLL_WRITE;
1066
 
1067
                        cond_resched();
1068
                        while (!(page = follow_page(vma, start, foll_flags))) {
1069
                                int ret;
1070
                                ret = handle_mm_fault(mm, vma, start,
1071
                                                foll_flags & FOLL_WRITE);
1072
                                if (ret & VM_FAULT_ERROR) {
1073
                                        if (ret & VM_FAULT_OOM)
1074
                                                return i ? i : -ENOMEM;
1075
                                        else if (ret & VM_FAULT_SIGBUS)
1076
                                                return i ? i : -EFAULT;
1077
                                        BUG();
1078
                                }
1079
                                if (ret & VM_FAULT_MAJOR)
1080
                                        tsk->maj_flt++;
1081
                                else
1082
                                        tsk->min_flt++;
1083
 
1084
                                /*
1085
                                 * The VM_FAULT_WRITE bit tells us that
1086
                                 * do_wp_page has broken COW when necessary,
1087
                                 * even if maybe_mkwrite decided not to set
1088
                                 * pte_write. We can thus safely do subsequent
1089
                                 * page lookups as if they were reads.
1090
                                 */
1091
                                if (ret & VM_FAULT_WRITE)
1092
                                        foll_flags &= ~FOLL_WRITE;
1093
 
1094
                                cond_resched();
1095
                        }
1096
                        if (pages) {
1097
                                pages[i] = page;
1098
 
1099
                                flush_anon_page(vma, page, start);
1100
                                flush_dcache_page(page);
1101
                        }
1102
                        if (vmas)
1103
                                vmas[i] = vma;
1104
                        i++;
1105
                        start += PAGE_SIZE;
1106
                        len--;
1107
                } while (len && start < vma->vm_end);
1108
        } while (len);
1109
        return i;
1110
}
1111
EXPORT_SYMBOL(get_user_pages);
1112
 
1113
pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
1114
{
1115
        pgd_t * pgd = pgd_offset(mm, addr);
1116
        pud_t * pud = pud_alloc(mm, pgd, addr);
1117
        if (pud) {
1118
                pmd_t * pmd = pmd_alloc(mm, pud, addr);
1119
                if (pmd)
1120
                        return pte_alloc_map_lock(mm, pmd, addr, ptl);
1121
        }
1122
        return NULL;
1123
}
1124
 
1125
/*
1126
 * This is the old fallback for page remapping.
1127
 *
1128
 * For historical reasons, it only allows reserved pages. Only
1129
 * old drivers should use this, and they needed to mark their
1130
 * pages reserved for the old functions anyway.
1131
 */
1132
static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
1133
{
1134
        int retval;
1135
        pte_t *pte;
1136
        spinlock_t *ptl;
1137
 
1138
        retval = -EINVAL;
1139
        if (PageAnon(page))
1140
                goto out;
1141
        retval = -ENOMEM;
1142
        flush_dcache_page(page);
1143
        pte = get_locked_pte(mm, addr, &ptl);
1144
        if (!pte)
1145
                goto out;
1146
        retval = -EBUSY;
1147
        if (!pte_none(*pte))
1148
                goto out_unlock;
1149
 
1150
        /* Ok, finally just insert the thing.. */
1151
        get_page(page);
1152
        inc_mm_counter(mm, file_rss);
1153
        page_add_file_rmap(page);
1154
        set_pte_at(mm, addr, pte, mk_pte(page, prot));
1155
 
1156
        retval = 0;
1157
out_unlock:
1158
        pte_unmap_unlock(pte, ptl);
1159
out:
1160
        return retval;
1161
}
1162
 
1163
/**
1164
 * vm_insert_page - insert single page into user vma
1165
 * @vma: user vma to map to
1166
 * @addr: target user address of this page
1167
 * @page: source kernel page
1168
 *
1169
 * This allows drivers to insert individual pages they've allocated
1170
 * into a user vma.
1171
 *
1172
 * The page has to be a nice clean _individual_ kernel allocation.
1173
 * If you allocate a compound page, you need to have marked it as
1174
 * such (__GFP_COMP), or manually just split the page up yourself
1175
 * (see split_page()).
1176
 *
1177
 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1178
 * took an arbitrary page protection parameter. This doesn't allow
1179
 * that. Your vma protection will have to be set up correctly, which
1180
 * means that if you want a shared writable mapping, you'd better
1181
 * ask for a shared writable mapping!
1182
 *
1183
 * The page does not need to be reserved.
1184
 */
1185
int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
1186
{
1187
        if (addr < vma->vm_start || addr >= vma->vm_end)
1188
                return -EFAULT;
1189
        if (!page_count(page))
1190
                return -EINVAL;
1191
        vma->vm_flags |= VM_INSERTPAGE;
1192
        return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
1193
}
1194
EXPORT_SYMBOL(vm_insert_page);
1195
 
1196
/**
1197
 * vm_insert_pfn - insert single pfn into user vma
1198
 * @vma: user vma to map to
1199
 * @addr: target user address of this page
1200
 * @pfn: source kernel pfn
1201
 *
1202
 * Similar to vm_inert_page, this allows drivers to insert individual pages
1203
 * they've allocated into a user vma. Same comments apply.
1204
 *
1205
 * This function should only be called from a vm_ops->fault handler, and
1206
 * in that case the handler should return NULL.
1207
 */
1208
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1209
                unsigned long pfn)
1210
{
1211
        struct mm_struct *mm = vma->vm_mm;
1212
        int retval;
1213
        pte_t *pte, entry;
1214
        spinlock_t *ptl;
1215
 
1216
        BUG_ON(!(vma->vm_flags & VM_PFNMAP));
1217
        BUG_ON(is_cow_mapping(vma->vm_flags));
1218
 
1219
        retval = -ENOMEM;
1220
        pte = get_locked_pte(mm, addr, &ptl);
1221
        if (!pte)
1222
                goto out;
1223
        retval = -EBUSY;
1224
        if (!pte_none(*pte))
1225
                goto out_unlock;
1226
 
1227
        /* Ok, finally just insert the thing.. */
1228
        entry = pfn_pte(pfn, vma->vm_page_prot);
1229
        set_pte_at(mm, addr, pte, entry);
1230
        update_mmu_cache(vma, addr, entry);
1231
 
1232
        retval = 0;
1233
out_unlock:
1234
        pte_unmap_unlock(pte, ptl);
1235
 
1236
out:
1237
        return retval;
1238
}
1239
EXPORT_SYMBOL(vm_insert_pfn);
1240
 
1241
/*
1242
 * maps a range of physical memory into the requested pages. the old
1243
 * mappings are removed. any references to nonexistent pages results
1244
 * in null mappings (currently treated as "copy-on-access")
1245
 */
1246
static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1247
                        unsigned long addr, unsigned long end,
1248
                        unsigned long pfn, pgprot_t prot)
1249
{
1250
        pte_t *pte;
1251
        spinlock_t *ptl;
1252
 
1253
        pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1254
        if (!pte)
1255
                return -ENOMEM;
1256
        arch_enter_lazy_mmu_mode();
1257
        do {
1258
                BUG_ON(!pte_none(*pte));
1259
                set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
1260
                pfn++;
1261
        } while (pte++, addr += PAGE_SIZE, addr != end);
1262
        arch_leave_lazy_mmu_mode();
1263
        pte_unmap_unlock(pte - 1, ptl);
1264
        return 0;
1265
}
1266
 
1267
static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1268
                        unsigned long addr, unsigned long end,
1269
                        unsigned long pfn, pgprot_t prot)
1270
{
1271
        pmd_t *pmd;
1272
        unsigned long next;
1273
 
1274
        pfn -= addr >> PAGE_SHIFT;
1275
        pmd = pmd_alloc(mm, pud, addr);
1276
        if (!pmd)
1277
                return -ENOMEM;
1278
        do {
1279
                next = pmd_addr_end(addr, end);
1280
                if (remap_pte_range(mm, pmd, addr, next,
1281
                                pfn + (addr >> PAGE_SHIFT), prot))
1282
                        return -ENOMEM;
1283
        } while (pmd++, addr = next, addr != end);
1284
        return 0;
1285
}
1286
 
1287
static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1288
                        unsigned long addr, unsigned long end,
1289
                        unsigned long pfn, pgprot_t prot)
1290
{
1291
        pud_t *pud;
1292
        unsigned long next;
1293
 
1294
        pfn -= addr >> PAGE_SHIFT;
1295
        pud = pud_alloc(mm, pgd, addr);
1296
        if (!pud)
1297
                return -ENOMEM;
1298
        do {
1299
                next = pud_addr_end(addr, end);
1300
                if (remap_pmd_range(mm, pud, addr, next,
1301
                                pfn + (addr >> PAGE_SHIFT), prot))
1302
                        return -ENOMEM;
1303
        } while (pud++, addr = next, addr != end);
1304
        return 0;
1305
}
1306
 
1307
/**
1308
 * remap_pfn_range - remap kernel memory to userspace
1309
 * @vma: user vma to map to
1310
 * @addr: target user address to start at
1311
 * @pfn: physical address of kernel memory
1312
 * @size: size of map area
1313
 * @prot: page protection flags for this mapping
1314
 *
1315
 *  Note: this is only safe if the mm semaphore is held when called.
1316
 */
1317
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1318
                    unsigned long pfn, unsigned long size, pgprot_t prot)
1319
{
1320
        pgd_t *pgd;
1321
        unsigned long next;
1322
        unsigned long end = addr + PAGE_ALIGN(size);
1323
        struct mm_struct *mm = vma->vm_mm;
1324
        int err;
1325
 
1326
        /*
1327
         * Physically remapped pages are special. Tell the
1328
         * rest of the world about it:
1329
         *   VM_IO tells people not to look at these pages
1330
         *      (accesses can have side effects).
1331
         *   VM_RESERVED is specified all over the place, because
1332
         *      in 2.4 it kept swapout's vma scan off this vma; but
1333
         *      in 2.6 the LRU scan won't even find its pages, so this
1334
         *      flag means no more than count its pages in reserved_vm,
1335
         *      and omit it from core dump, even when VM_IO turned off.
1336
         *   VM_PFNMAP tells the core MM that the base pages are just
1337
         *      raw PFN mappings, and do not have a "struct page" associated
1338
         *      with them.
1339
         *
1340
         * There's a horrible special case to handle copy-on-write
1341
         * behaviour that some programs depend on. We mark the "original"
1342
         * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1343
         */
1344
        if (is_cow_mapping(vma->vm_flags)) {
1345
                if (addr != vma->vm_start || end != vma->vm_end)
1346
                        return -EINVAL;
1347
                vma->vm_pgoff = pfn;
1348
        }
1349
 
1350
        vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
1351
 
1352
        BUG_ON(addr >= end);
1353
        pfn -= addr >> PAGE_SHIFT;
1354
        pgd = pgd_offset(mm, addr);
1355
        flush_cache_range(vma, addr, end);
1356
        do {
1357
                next = pgd_addr_end(addr, end);
1358
                err = remap_pud_range(mm, pgd, addr, next,
1359
                                pfn + (addr >> PAGE_SHIFT), prot);
1360
                if (err)
1361
                        break;
1362
        } while (pgd++, addr = next, addr != end);
1363
        return err;
1364
}
1365
EXPORT_SYMBOL(remap_pfn_range);
1366
 
1367
static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1368
                                     unsigned long addr, unsigned long end,
1369
                                     pte_fn_t fn, void *data)
1370
{
1371
        pte_t *pte;
1372
        int err;
1373
        struct page *pmd_page;
1374
        spinlock_t *uninitialized_var(ptl);
1375
 
1376
        pte = (mm == &init_mm) ?
1377
                pte_alloc_kernel(pmd, addr) :
1378
                pte_alloc_map_lock(mm, pmd, addr, &ptl);
1379
        if (!pte)
1380
                return -ENOMEM;
1381
 
1382
        BUG_ON(pmd_huge(*pmd));
1383
 
1384
        pmd_page = pmd_page(*pmd);
1385
 
1386
        do {
1387
                err = fn(pte, pmd_page, addr, data);
1388
                if (err)
1389
                        break;
1390
        } while (pte++, addr += PAGE_SIZE, addr != end);
1391
 
1392
        if (mm != &init_mm)
1393
                pte_unmap_unlock(pte-1, ptl);
1394
        return err;
1395
}
1396
 
1397
static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1398
                                     unsigned long addr, unsigned long end,
1399
                                     pte_fn_t fn, void *data)
1400
{
1401
        pmd_t *pmd;
1402
        unsigned long next;
1403
        int err;
1404
 
1405
        pmd = pmd_alloc(mm, pud, addr);
1406
        if (!pmd)
1407
                return -ENOMEM;
1408
        do {
1409
                next = pmd_addr_end(addr, end);
1410
                err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1411
                if (err)
1412
                        break;
1413
        } while (pmd++, addr = next, addr != end);
1414
        return err;
1415
}
1416
 
1417
static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1418
                                     unsigned long addr, unsigned long end,
1419
                                     pte_fn_t fn, void *data)
1420
{
1421
        pud_t *pud;
1422
        unsigned long next;
1423
        int err;
1424
 
1425
        pud = pud_alloc(mm, pgd, addr);
1426
        if (!pud)
1427
                return -ENOMEM;
1428
        do {
1429
                next = pud_addr_end(addr, end);
1430
                err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1431
                if (err)
1432
                        break;
1433
        } while (pud++, addr = next, addr != end);
1434
        return err;
1435
}
1436
 
1437
/*
1438
 * Scan a region of virtual memory, filling in page tables as necessary
1439
 * and calling a provided function on each leaf page table.
1440
 */
1441
int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1442
                        unsigned long size, pte_fn_t fn, void *data)
1443
{
1444
        pgd_t *pgd;
1445
        unsigned long next;
1446
        unsigned long end = addr + size;
1447
        int err;
1448
 
1449
        BUG_ON(addr >= end);
1450
        pgd = pgd_offset(mm, addr);
1451
        do {
1452
                next = pgd_addr_end(addr, end);
1453
                err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
1454
                if (err)
1455
                        break;
1456
        } while (pgd++, addr = next, addr != end);
1457
        return err;
1458
}
1459
EXPORT_SYMBOL_GPL(apply_to_page_range);
1460
 
1461
/*
1462
 * handle_pte_fault chooses page fault handler according to an entry
1463
 * which was read non-atomically.  Before making any commitment, on
1464
 * those architectures or configurations (e.g. i386 with PAE) which
1465
 * might give a mix of unmatched parts, do_swap_page and do_file_page
1466
 * must check under lock before unmapping the pte and proceeding
1467
 * (but do_wp_page is only called after already making such a check;
1468
 * and do_anonymous_page and do_no_page can safely check later on).
1469
 */
1470
static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
1471
                                pte_t *page_table, pte_t orig_pte)
1472
{
1473
        int same = 1;
1474
#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1475
        if (sizeof(pte_t) > sizeof(unsigned long)) {
1476
                spinlock_t *ptl = pte_lockptr(mm, pmd);
1477
                spin_lock(ptl);
1478
                same = pte_same(*page_table, orig_pte);
1479
                spin_unlock(ptl);
1480
        }
1481
#endif
1482
        pte_unmap(page_table);
1483
        return same;
1484
}
1485
 
1486
/*
1487
 * Do pte_mkwrite, but only if the vma says VM_WRITE.  We do this when
1488
 * servicing faults for write access.  In the normal case, do always want
1489
 * pte_mkwrite.  But get_user_pages can cause write faults for mappings
1490
 * that do not have writing enabled, when used by access_process_vm.
1491
 */
1492
static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1493
{
1494
        if (likely(vma->vm_flags & VM_WRITE))
1495
                pte = pte_mkwrite(pte);
1496
        return pte;
1497
}
1498
 
1499
static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
1500
{
1501
        /*
1502
         * If the source page was a PFN mapping, we don't have
1503
         * a "struct page" for it. We do a best-effort copy by
1504
         * just copying from the original user address. If that
1505
         * fails, we just zero-fill it. Live with it.
1506
         */
1507
        if (unlikely(!src)) {
1508
                void *kaddr = kmap_atomic(dst, KM_USER0);
1509
                void __user *uaddr = (void __user *)(va & PAGE_MASK);
1510
 
1511
                /*
1512
                 * This really shouldn't fail, because the page is there
1513
                 * in the page tables. But it might just be unreadable,
1514
                 * in which case we just give up and fill the result with
1515
                 * zeroes.
1516
                 */
1517
                if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
1518
                        memset(kaddr, 0, PAGE_SIZE);
1519
                kunmap_atomic(kaddr, KM_USER0);
1520
                flush_dcache_page(dst);
1521
                return;
1522
 
1523
        }
1524
        copy_user_highpage(dst, src, va, vma);
1525
}
1526
 
1527
/*
1528
 * This routine handles present pages, when users try to write
1529
 * to a shared page. It is done by copying the page to a new address
1530
 * and decrementing the shared-page counter for the old page.
1531
 *
1532
 * Note that this routine assumes that the protection checks have been
1533
 * done by the caller (the low-level page fault routine in most cases).
1534
 * Thus we can safely just mark it writable once we've done any necessary
1535
 * COW.
1536
 *
1537
 * We also mark the page dirty at this point even though the page will
1538
 * change only once the write actually happens. This avoids a few races,
1539
 * and potentially makes it more efficient.
1540
 *
1541
 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1542
 * but allow concurrent faults), with pte both mapped and locked.
1543
 * We return with mmap_sem still held, but pte unmapped and unlocked.
1544
 */
1545
static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1546
                unsigned long address, pte_t *page_table, pmd_t *pmd,
1547
                spinlock_t *ptl, pte_t orig_pte)
1548
{
1549
        struct page *old_page, *new_page;
1550
        pte_t entry;
1551
        int reuse = 0, ret = 0;
1552
        int page_mkwrite = 0;
1553
        struct page *dirty_page = NULL;
1554
 
1555
        old_page = vm_normal_page(vma, address, orig_pte);
1556
        if (!old_page)
1557
                goto gotten;
1558
 
1559
        /*
1560
         * Take out anonymous pages first, anonymous shared vmas are
1561
         * not dirty accountable.
1562
         */
1563
        if (PageAnon(old_page)) {
1564
                if (!TestSetPageLocked(old_page)) {
1565
                        reuse = can_share_swap_page(old_page);
1566
                        unlock_page(old_page);
1567
                }
1568
        } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
1569
                                        (VM_WRITE|VM_SHARED))) {
1570
                /*
1571
                 * Only catch write-faults on shared writable pages,
1572
                 * read-only shared pages can get COWed by
1573
                 * get_user_pages(.write=1, .force=1).
1574
                 */
1575
                if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
1576
                        /*
1577
                         * Notify the address space that the page is about to
1578
                         * become writable so that it can prohibit this or wait
1579
                         * for the page to get into an appropriate state.
1580
                         *
1581
                         * We do this without the lock held, so that it can
1582
                         * sleep if it needs to.
1583
                         */
1584
                        page_cache_get(old_page);
1585
                        pte_unmap_unlock(page_table, ptl);
1586
 
1587
                        if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
1588
                                goto unwritable_page;
1589
 
1590
                        /*
1591
                         * Since we dropped the lock we need to revalidate
1592
                         * the PTE as someone else may have changed it.  If
1593
                         * they did, we just return, as we can count on the
1594
                         * MMU to tell us if they didn't also make it writable.
1595
                         */
1596
                        page_table = pte_offset_map_lock(mm, pmd, address,
1597
                                                         &ptl);
1598
                        page_cache_release(old_page);
1599
                        if (!pte_same(*page_table, orig_pte))
1600
                                goto unlock;
1601
 
1602
                        page_mkwrite = 1;
1603
                }
1604
                dirty_page = old_page;
1605
                get_page(dirty_page);
1606
                reuse = 1;
1607
        }
1608
 
1609
        if (reuse) {
1610
                flush_cache_page(vma, address, pte_pfn(orig_pte));
1611
                entry = pte_mkyoung(orig_pte);
1612
                entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1613
                if (ptep_set_access_flags(vma, address, page_table, entry,1))
1614
                        update_mmu_cache(vma, address, entry);
1615
                ret |= VM_FAULT_WRITE;
1616
                goto unlock;
1617
        }
1618
 
1619
        /*
1620
         * Ok, we need to copy. Oh, well..
1621
         */
1622
        page_cache_get(old_page);
1623
gotten:
1624
        pte_unmap_unlock(page_table, ptl);
1625
 
1626
        if (unlikely(anon_vma_prepare(vma)))
1627
                goto oom;
1628
        VM_BUG_ON(old_page == ZERO_PAGE(0));
1629
        new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1630
        if (!new_page)
1631
                goto oom;
1632
        cow_user_page(new_page, old_page, address, vma);
1633
 
1634
        /*
1635
         * Re-check the pte - we dropped the lock
1636
         */
1637
        page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1638
        if (likely(pte_same(*page_table, orig_pte))) {
1639
                if (old_page) {
1640
                        page_remove_rmap(old_page, vma);
1641
                        if (!PageAnon(old_page)) {
1642
                                dec_mm_counter(mm, file_rss);
1643
                                inc_mm_counter(mm, anon_rss);
1644
                        }
1645
                } else
1646
                        inc_mm_counter(mm, anon_rss);
1647
                flush_cache_page(vma, address, pte_pfn(orig_pte));
1648
                entry = mk_pte(new_page, vma->vm_page_prot);
1649
                entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1650
                /*
1651
                 * Clear the pte entry and flush it first, before updating the
1652
                 * pte with the new entry. This will avoid a race condition
1653
                 * seen in the presence of one thread doing SMC and another
1654
                 * thread doing COW.
1655
                 */
1656
                ptep_clear_flush(vma, address, page_table);
1657
                set_pte_at(mm, address, page_table, entry);
1658
                update_mmu_cache(vma, address, entry);
1659
                lru_cache_add_active(new_page);
1660
                page_add_new_anon_rmap(new_page, vma, address);
1661
 
1662
                /* Free the old page.. */
1663
                new_page = old_page;
1664
                ret |= VM_FAULT_WRITE;
1665
        }
1666
        if (new_page)
1667
                page_cache_release(new_page);
1668
        if (old_page)
1669
                page_cache_release(old_page);
1670
unlock:
1671
        pte_unmap_unlock(page_table, ptl);
1672
        if (dirty_page) {
1673
                if (vma->vm_file)
1674
                        file_update_time(vma->vm_file);
1675
 
1676
                /*
1677
                 * Yes, Virginia, this is actually required to prevent a race
1678
                 * with clear_page_dirty_for_io() from clearing the page dirty
1679
                 * bit after it clear all dirty ptes, but before a racing
1680
                 * do_wp_page installs a dirty pte.
1681
                 *
1682
                 * do_no_page is protected similarly.
1683
                 */
1684
                wait_on_page_locked(dirty_page);
1685
                set_page_dirty_balance(dirty_page, page_mkwrite);
1686
                put_page(dirty_page);
1687
        }
1688
        return ret;
1689
oom:
1690
        if (old_page)
1691
                page_cache_release(old_page);
1692
        return VM_FAULT_OOM;
1693
 
1694
unwritable_page:
1695
        page_cache_release(old_page);
1696
        return VM_FAULT_SIGBUS;
1697
}
1698
 
1699
/*
1700
 * Helper functions for unmap_mapping_range().
1701
 *
1702
 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1703
 *
1704
 * We have to restart searching the prio_tree whenever we drop the lock,
1705
 * since the iterator is only valid while the lock is held, and anyway
1706
 * a later vma might be split and reinserted earlier while lock dropped.
1707
 *
1708
 * The list of nonlinear vmas could be handled more efficiently, using
1709
 * a placeholder, but handle it in the same way until a need is shown.
1710
 * It is important to search the prio_tree before nonlinear list: a vma
1711
 * may become nonlinear and be shifted from prio_tree to nonlinear list
1712
 * while the lock is dropped; but never shifted from list to prio_tree.
1713
 *
1714
 * In order to make forward progress despite restarting the search,
1715
 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1716
 * quickly skip it next time around.  Since the prio_tree search only
1717
 * shows us those vmas affected by unmapping the range in question, we
1718
 * can't efficiently keep all vmas in step with mapping->truncate_count:
1719
 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1720
 * mapping->truncate_count and vma->vm_truncate_count are protected by
1721
 * i_mmap_lock.
1722
 *
1723
 * In order to make forward progress despite repeatedly restarting some
1724
 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1725
 * and restart from that address when we reach that vma again.  It might
1726
 * have been split or merged, shrunk or extended, but never shifted: so
1727
 * restart_addr remains valid so long as it remains in the vma's range.
1728
 * unmap_mapping_range forces truncate_count to leap over page-aligned
1729
 * values so we can save vma's restart_addr in its truncate_count field.
1730
 */
1731
#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1732
 
1733
static void reset_vma_truncate_counts(struct address_space *mapping)
1734
{
1735
        struct vm_area_struct *vma;
1736
        struct prio_tree_iter iter;
1737
 
1738
        vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1739
                vma->vm_truncate_count = 0;
1740
        list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1741
                vma->vm_truncate_count = 0;
1742
}
1743
 
1744
static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1745
                unsigned long start_addr, unsigned long end_addr,
1746
                struct zap_details *details)
1747
{
1748
        unsigned long restart_addr;
1749
        int need_break;
1750
 
1751
        /*
1752
         * files that support invalidating or truncating portions of the
1753
         * file from under mmaped areas must have their ->fault function
1754
         * return a locked page (and set VM_FAULT_LOCKED in the return).
1755
         * This provides synchronisation against concurrent unmapping here.
1756
         */
1757
 
1758
again:
1759
        restart_addr = vma->vm_truncate_count;
1760
        if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1761
                start_addr = restart_addr;
1762
                if (start_addr >= end_addr) {
1763
                        /* Top of vma has been split off since last time */
1764
                        vma->vm_truncate_count = details->truncate_count;
1765
                        return 0;
1766
                }
1767
        }
1768
 
1769
        restart_addr = zap_page_range(vma, start_addr,
1770
                                        end_addr - start_addr, details);
1771
        need_break = need_resched() ||
1772
                        need_lockbreak(details->i_mmap_lock);
1773
 
1774
        if (restart_addr >= end_addr) {
1775
                /* We have now completed this vma: mark it so */
1776
                vma->vm_truncate_count = details->truncate_count;
1777
                if (!need_break)
1778
                        return 0;
1779
        } else {
1780
                /* Note restart_addr in vma's truncate_count field */
1781
                vma->vm_truncate_count = restart_addr;
1782
                if (!need_break)
1783
                        goto again;
1784
        }
1785
 
1786
        spin_unlock(details->i_mmap_lock);
1787
        cond_resched();
1788
        spin_lock(details->i_mmap_lock);
1789
        return -EINTR;
1790
}
1791
 
1792
static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1793
                                            struct zap_details *details)
1794
{
1795
        struct vm_area_struct *vma;
1796
        struct prio_tree_iter iter;
1797
        pgoff_t vba, vea, zba, zea;
1798
 
1799
restart:
1800
        vma_prio_tree_foreach(vma, &iter, root,
1801
                        details->first_index, details->last_index) {
1802
                /* Skip quickly over those we have already dealt with */
1803
                if (vma->vm_truncate_count == details->truncate_count)
1804
                        continue;
1805
 
1806
                vba = vma->vm_pgoff;
1807
                vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1808
                /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1809
                zba = details->first_index;
1810
                if (zba < vba)
1811
                        zba = vba;
1812
                zea = details->last_index;
1813
                if (zea > vea)
1814
                        zea = vea;
1815
 
1816
                if (unmap_mapping_range_vma(vma,
1817
                        ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1818
                        ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1819
                                details) < 0)
1820
                        goto restart;
1821
        }
1822
}
1823
 
1824
static inline void unmap_mapping_range_list(struct list_head *head,
1825
                                            struct zap_details *details)
1826
{
1827
        struct vm_area_struct *vma;
1828
 
1829
        /*
1830
         * In nonlinear VMAs there is no correspondence between virtual address
1831
         * offset and file offset.  So we must perform an exhaustive search
1832
         * across *all* the pages in each nonlinear VMA, not just the pages
1833
         * whose virtual address lies outside the file truncation point.
1834
         */
1835
restart:
1836
        list_for_each_entry(vma, head, shared.vm_set.list) {
1837
                /* Skip quickly over those we have already dealt with */
1838
                if (vma->vm_truncate_count == details->truncate_count)
1839
                        continue;
1840
                details->nonlinear_vma = vma;
1841
                if (unmap_mapping_range_vma(vma, vma->vm_start,
1842
                                        vma->vm_end, details) < 0)
1843
                        goto restart;
1844
        }
1845
}
1846
 
1847
/**
1848
 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
1849
 * @mapping: the address space containing mmaps to be unmapped.
1850
 * @holebegin: byte in first page to unmap, relative to the start of
1851
 * the underlying file.  This will be rounded down to a PAGE_SIZE
1852
 * boundary.  Note that this is different from vmtruncate(), which
1853
 * must keep the partial page.  In contrast, we must get rid of
1854
 * partial pages.
1855
 * @holelen: size of prospective hole in bytes.  This will be rounded
1856
 * up to a PAGE_SIZE boundary.  A holelen of zero truncates to the
1857
 * end of the file.
1858
 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1859
 * but 0 when invalidating pagecache, don't throw away private data.
1860
 */
1861
void unmap_mapping_range(struct address_space *mapping,
1862
                loff_t const holebegin, loff_t const holelen, int even_cows)
1863
{
1864
        struct zap_details details;
1865
        pgoff_t hba = holebegin >> PAGE_SHIFT;
1866
        pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1867
 
1868
        /* Check for overflow. */
1869
        if (sizeof(holelen) > sizeof(hlen)) {
1870
                long long holeend =
1871
                        (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1872
                if (holeend & ~(long long)ULONG_MAX)
1873
                        hlen = ULONG_MAX - hba + 1;
1874
        }
1875
 
1876
        details.check_mapping = even_cows? NULL: mapping;
1877
        details.nonlinear_vma = NULL;
1878
        details.first_index = hba;
1879
        details.last_index = hba + hlen - 1;
1880
        if (details.last_index < details.first_index)
1881
                details.last_index = ULONG_MAX;
1882
        details.i_mmap_lock = &mapping->i_mmap_lock;
1883
 
1884
        spin_lock(&mapping->i_mmap_lock);
1885
 
1886
        /* Protect against endless unmapping loops */
1887
        mapping->truncate_count++;
1888
        if (unlikely(is_restart_addr(mapping->truncate_count))) {
1889
                if (mapping->truncate_count == 0)
1890
                        reset_vma_truncate_counts(mapping);
1891
                mapping->truncate_count++;
1892
        }
1893
        details.truncate_count = mapping->truncate_count;
1894
 
1895
        if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1896
                unmap_mapping_range_tree(&mapping->i_mmap, &details);
1897
        if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1898
                unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1899
        spin_unlock(&mapping->i_mmap_lock);
1900
}
1901
EXPORT_SYMBOL(unmap_mapping_range);
1902
 
1903
/**
1904
 * vmtruncate - unmap mappings "freed" by truncate() syscall
1905
 * @inode: inode of the file used
1906
 * @offset: file offset to start truncating
1907
 *
1908
 * NOTE! We have to be ready to update the memory sharing
1909
 * between the file and the memory map for a potential last
1910
 * incomplete page.  Ugly, but necessary.
1911
 */
1912
int vmtruncate(struct inode * inode, loff_t offset)
1913
{
1914
        struct address_space *mapping = inode->i_mapping;
1915
        unsigned long limit;
1916
 
1917
        if (inode->i_size < offset)
1918
                goto do_expand;
1919
        /*
1920
         * truncation of in-use swapfiles is disallowed - it would cause
1921
         * subsequent swapout to scribble on the now-freed blocks.
1922
         */
1923
        if (IS_SWAPFILE(inode))
1924
                goto out_busy;
1925
        i_size_write(inode, offset);
1926
 
1927
        /*
1928
         * unmap_mapping_range is called twice, first simply for efficiency
1929
         * so that truncate_inode_pages does fewer single-page unmaps. However
1930
         * after this first call, and before truncate_inode_pages finishes,
1931
         * it is possible for private pages to be COWed, which remain after
1932
         * truncate_inode_pages finishes, hence the second unmap_mapping_range
1933
         * call must be made for correctness.
1934
         */
1935
        unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1936
        truncate_inode_pages(mapping, offset);
1937
        unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1938
        goto out_truncate;
1939
 
1940
do_expand:
1941
        limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1942
        if (limit != RLIM_INFINITY && offset > limit)
1943
                goto out_sig;
1944
        if (offset > inode->i_sb->s_maxbytes)
1945
                goto out_big;
1946
        i_size_write(inode, offset);
1947
 
1948
out_truncate:
1949
        if (inode->i_op && inode->i_op->truncate)
1950
                inode->i_op->truncate(inode);
1951
        return 0;
1952
out_sig:
1953
        send_sig(SIGXFSZ, current, 0);
1954
out_big:
1955
        return -EFBIG;
1956
out_busy:
1957
        return -ETXTBSY;
1958
}
1959
EXPORT_SYMBOL(vmtruncate);
1960
 
1961
int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
1962
{
1963
        struct address_space *mapping = inode->i_mapping;
1964
 
1965
        /*
1966
         * If the underlying filesystem is not going to provide
1967
         * a way to truncate a range of blocks (punch a hole) -
1968
         * we should return failure right now.
1969
         */
1970
        if (!inode->i_op || !inode->i_op->truncate_range)
1971
                return -ENOSYS;
1972
 
1973
        mutex_lock(&inode->i_mutex);
1974
        down_write(&inode->i_alloc_sem);
1975
        unmap_mapping_range(mapping, offset, (end - offset), 1);
1976
        truncate_inode_pages_range(mapping, offset, end);
1977
        unmap_mapping_range(mapping, offset, (end - offset), 1);
1978
        inode->i_op->truncate_range(inode, offset, end);
1979
        up_write(&inode->i_alloc_sem);
1980
        mutex_unlock(&inode->i_mutex);
1981
 
1982
        return 0;
1983
}
1984
 
1985
/**
1986
 * swapin_readahead - swap in pages in hope we need them soon
1987
 * @entry: swap entry of this memory
1988
 * @addr: address to start
1989
 * @vma: user vma this addresses belong to
1990
 *
1991
 * Primitive swap readahead code. We simply read an aligned block of
1992
 * (1 << page_cluster) entries in the swap area. This method is chosen
1993
 * because it doesn't cost us any seek time.  We also make sure to queue
1994
 * the 'original' request together with the readahead ones...
1995
 *
1996
 * This has been extended to use the NUMA policies from the mm triggering
1997
 * the readahead.
1998
 *
1999
 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
2000
 */
2001
void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
2002
{
2003
#ifdef CONFIG_NUMA
2004
        struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
2005
#endif
2006
        int i, num;
2007
        struct page *new_page;
2008
        unsigned long offset;
2009
 
2010
        /*
2011
         * Get the number of handles we should do readahead io to.
2012
         */
2013
        num = valid_swaphandles(entry, &offset);
2014
        for (i = 0; i < num; offset++, i++) {
2015
                /* Ok, do the async read-ahead now */
2016
                new_page = read_swap_cache_async(swp_entry(swp_type(entry),
2017
                                                           offset), vma, addr);
2018
                if (!new_page)
2019
                        break;
2020
                page_cache_release(new_page);
2021
#ifdef CONFIG_NUMA
2022
                /*
2023
                 * Find the next applicable VMA for the NUMA policy.
2024
                 */
2025
                addr += PAGE_SIZE;
2026
                if (addr == 0)
2027
                        vma = NULL;
2028
                if (vma) {
2029
                        if (addr >= vma->vm_end) {
2030
                                vma = next_vma;
2031
                                next_vma = vma ? vma->vm_next : NULL;
2032
                        }
2033
                        if (vma && addr < vma->vm_start)
2034
                                vma = NULL;
2035
                } else {
2036
                        if (next_vma && addr >= next_vma->vm_start) {
2037
                                vma = next_vma;
2038
                                next_vma = vma->vm_next;
2039
                        }
2040
                }
2041
#endif
2042
        }
2043
        lru_add_drain();        /* Push any new pages onto the LRU now */
2044
}
2045
 
2046
/*
2047
 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2048
 * but allow concurrent faults), and pte mapped but not yet locked.
2049
 * We return with mmap_sem still held, but pte unmapped and unlocked.
2050
 */
2051
static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2052
                unsigned long address, pte_t *page_table, pmd_t *pmd,
2053
                int write_access, pte_t orig_pte)
2054
{
2055
        spinlock_t *ptl;
2056
        struct page *page;
2057
        swp_entry_t entry;
2058
        pte_t pte;
2059
        int ret = 0;
2060
 
2061
        if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2062
                goto out;
2063
 
2064
        entry = pte_to_swp_entry(orig_pte);
2065
        if (is_migration_entry(entry)) {
2066
                migration_entry_wait(mm, pmd, address);
2067
                goto out;
2068
        }
2069
        delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2070
        page = lookup_swap_cache(entry);
2071
        if (!page) {
2072
                grab_swap_token(); /* Contend for token _before_ read-in */
2073
                swapin_readahead(entry, address, vma);
2074
                page = read_swap_cache_async(entry, vma, address);
2075
                if (!page) {
2076
                        /*
2077
                         * Back out if somebody else faulted in this pte
2078
                         * while we released the pte lock.
2079
                         */
2080
                        page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2081
                        if (likely(pte_same(*page_table, orig_pte)))
2082
                                ret = VM_FAULT_OOM;
2083
                        delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2084
                        goto unlock;
2085
                }
2086
 
2087
                /* Had to read the page from swap area: Major fault */
2088
                ret = VM_FAULT_MAJOR;
2089
                count_vm_event(PGMAJFAULT);
2090
        }
2091
 
2092
        mark_page_accessed(page);
2093
        lock_page(page);
2094
        delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2095
 
2096
        /*
2097
         * Back out if somebody else already faulted in this pte.
2098
         */
2099
        page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2100
        if (unlikely(!pte_same(*page_table, orig_pte)))
2101
                goto out_nomap;
2102
 
2103
        if (unlikely(!PageUptodate(page))) {
2104
                ret = VM_FAULT_SIGBUS;
2105
                goto out_nomap;
2106
        }
2107
 
2108
        /* The page isn't present yet, go ahead with the fault. */
2109
 
2110
        inc_mm_counter(mm, anon_rss);
2111
        pte = mk_pte(page, vma->vm_page_prot);
2112
        if (write_access && can_share_swap_page(page)) {
2113
                pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2114
                write_access = 0;
2115
        }
2116
 
2117
        flush_icache_page(vma, page);
2118
        set_pte_at(mm, address, page_table, pte);
2119
        page_add_anon_rmap(page, vma, address);
2120
 
2121
        swap_free(entry);
2122
        if (vm_swap_full())
2123
                remove_exclusive_swap_page(page);
2124
        unlock_page(page);
2125
 
2126
        if (write_access) {
2127
                /* XXX: We could OR the do_wp_page code with this one? */
2128
                if (do_wp_page(mm, vma, address,
2129
                                page_table, pmd, ptl, pte) & VM_FAULT_OOM)
2130
                        ret = VM_FAULT_OOM;
2131
                goto out;
2132
        }
2133
 
2134
        /* No need to invalidate - it was non-present before */
2135
        update_mmu_cache(vma, address, pte);
2136
unlock:
2137
        pte_unmap_unlock(page_table, ptl);
2138
out:
2139
        return ret;
2140
out_nomap:
2141
        pte_unmap_unlock(page_table, ptl);
2142
        unlock_page(page);
2143
        page_cache_release(page);
2144
        return ret;
2145
}
2146
 
2147
/*
2148
 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2149
 * but allow concurrent faults), and pte mapped but not yet locked.
2150
 * We return with mmap_sem still held, but pte unmapped and unlocked.
2151
 */
2152
static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2153
                unsigned long address, pte_t *page_table, pmd_t *pmd,
2154
                int write_access)
2155
{
2156
        struct page *page;
2157
        spinlock_t *ptl;
2158
        pte_t entry;
2159
 
2160
        /* Allocate our own private page. */
2161
        pte_unmap(page_table);
2162
 
2163
        if (unlikely(anon_vma_prepare(vma)))
2164
                goto oom;
2165
        page = alloc_zeroed_user_highpage_movable(vma, address);
2166
        if (!page)
2167
                goto oom;
2168
 
2169
        entry = mk_pte(page, vma->vm_page_prot);
2170
        entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2171
 
2172
        page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2173
        if (!pte_none(*page_table))
2174
                goto release;
2175
        inc_mm_counter(mm, anon_rss);
2176
        lru_cache_add_active(page);
2177
        page_add_new_anon_rmap(page, vma, address);
2178
        set_pte_at(mm, address, page_table, entry);
2179
 
2180
        /* No need to invalidate - it was non-present before */
2181
        update_mmu_cache(vma, address, entry);
2182
unlock:
2183
        pte_unmap_unlock(page_table, ptl);
2184
        return 0;
2185
release:
2186
        page_cache_release(page);
2187
        goto unlock;
2188
oom:
2189
        return VM_FAULT_OOM;
2190
}
2191
 
2192
/*
2193
 * __do_fault() tries to create a new page mapping. It aggressively
2194
 * tries to share with existing pages, but makes a separate copy if
2195
 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2196
 * the next page fault.
2197
 *
2198
 * As this is called only for pages that do not currently exist, we
2199
 * do not need to flush old virtual caches or the TLB.
2200
 *
2201
 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2202
 * but allow concurrent faults), and pte neither mapped nor locked.
2203
 * We return with mmap_sem still held, but pte unmapped and unlocked.
2204
 */
2205
static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2206
                unsigned long address, pmd_t *pmd,
2207
                pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
2208
{
2209
        pte_t *page_table;
2210
        spinlock_t *ptl;
2211
        struct page *page;
2212
        pte_t entry;
2213
        int anon = 0;
2214
        struct page *dirty_page = NULL;
2215
        struct vm_fault vmf;
2216
        int ret;
2217
        int page_mkwrite = 0;
2218
 
2219
        vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2220
        vmf.pgoff = pgoff;
2221
        vmf.flags = flags;
2222
        vmf.page = NULL;
2223
 
2224
        BUG_ON(vma->vm_flags & VM_PFNMAP);
2225
 
2226
        if (likely(vma->vm_ops->fault)) {
2227
                ret = vma->vm_ops->fault(vma, &vmf);
2228
                if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2229
                        return ret;
2230
        } else {
2231
                /* Legacy ->nopage path */
2232
                ret = 0;
2233
                vmf.page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
2234
                /* no page was available -- either SIGBUS or OOM */
2235
                if (unlikely(vmf.page == NOPAGE_SIGBUS))
2236
                        return VM_FAULT_SIGBUS;
2237
                else if (unlikely(vmf.page == NOPAGE_OOM))
2238
                        return VM_FAULT_OOM;
2239
        }
2240
 
2241
        /*
2242
         * For consistency in subsequent calls, make the faulted page always
2243
         * locked.
2244
         */
2245
        if (unlikely(!(ret & VM_FAULT_LOCKED)))
2246
                lock_page(vmf.page);
2247
        else
2248
                VM_BUG_ON(!PageLocked(vmf.page));
2249
 
2250
        /*
2251
         * Should we do an early C-O-W break?
2252
         */
2253
        page = vmf.page;
2254
        if (flags & FAULT_FLAG_WRITE) {
2255
                if (!(vma->vm_flags & VM_SHARED)) {
2256
                        anon = 1;
2257
                        if (unlikely(anon_vma_prepare(vma))) {
2258
                                ret = VM_FAULT_OOM;
2259
                                goto out;
2260
                        }
2261
                        page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2262
                                                vma, address);
2263
                        if (!page) {
2264
                                ret = VM_FAULT_OOM;
2265
                                goto out;
2266
                        }
2267
                        copy_user_highpage(page, vmf.page, address, vma);
2268
                } else {
2269
                        /*
2270
                         * If the page will be shareable, see if the backing
2271
                         * address space wants to know that the page is about
2272
                         * to become writable
2273
                         */
2274
                        if (vma->vm_ops->page_mkwrite) {
2275
                                unlock_page(page);
2276
                                if (vma->vm_ops->page_mkwrite(vma, page) < 0) {
2277
                                        ret = VM_FAULT_SIGBUS;
2278
                                        anon = 1; /* no anon but release vmf.page */
2279
                                        goto out_unlocked;
2280
                                }
2281
                                lock_page(page);
2282
                                /*
2283
                                 * XXX: this is not quite right (racy vs
2284
                                 * invalidate) to unlock and relock the page
2285
                                 * like this, however a better fix requires
2286
                                 * reworking page_mkwrite locking API, which
2287
                                 * is better done later.
2288
                                 */
2289
                                if (!page->mapping) {
2290
                                        ret = 0;
2291
                                        anon = 1; /* no anon but release vmf.page */
2292
                                        goto out;
2293
                                }
2294
                                page_mkwrite = 1;
2295
                        }
2296
                }
2297
 
2298
        }
2299
 
2300
        page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2301
 
2302
        /*
2303
         * This silly early PAGE_DIRTY setting removes a race
2304
         * due to the bad i386 page protection. But it's valid
2305
         * for other architectures too.
2306
         *
2307
         * Note that if write_access is true, we either now have
2308
         * an exclusive copy of the page, or this is a shared mapping,
2309
         * so we can make it writable and dirty to avoid having to
2310
         * handle that later.
2311
         */
2312
        /* Only go through if we didn't race with anybody else... */
2313
        if (likely(pte_same(*page_table, orig_pte))) {
2314
                flush_icache_page(vma, page);
2315
                entry = mk_pte(page, vma->vm_page_prot);
2316
                if (flags & FAULT_FLAG_WRITE)
2317
                        entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2318
                set_pte_at(mm, address, page_table, entry);
2319
                if (anon) {
2320
                        inc_mm_counter(mm, anon_rss);
2321
                        lru_cache_add_active(page);
2322
                        page_add_new_anon_rmap(page, vma, address);
2323
                } else {
2324
                        inc_mm_counter(mm, file_rss);
2325
                        page_add_file_rmap(page);
2326
                        if (flags & FAULT_FLAG_WRITE) {
2327
                                dirty_page = page;
2328
                                get_page(dirty_page);
2329
                        }
2330
                }
2331
 
2332
                /* no need to invalidate: a not-present page won't be cached */
2333
                update_mmu_cache(vma, address, entry);
2334
        } else {
2335
                if (anon)
2336
                        page_cache_release(page);
2337
                else
2338
                        anon = 1; /* no anon but release faulted_page */
2339
        }
2340
 
2341
        pte_unmap_unlock(page_table, ptl);
2342
 
2343
out:
2344
        unlock_page(vmf.page);
2345
out_unlocked:
2346
        if (anon)
2347
                page_cache_release(vmf.page);
2348
        else if (dirty_page) {
2349
                if (vma->vm_file)
2350
                        file_update_time(vma->vm_file);
2351
 
2352
                set_page_dirty_balance(dirty_page, page_mkwrite);
2353
                put_page(dirty_page);
2354
        }
2355
 
2356
        return ret;
2357
}
2358
 
2359
static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2360
                unsigned long address, pte_t *page_table, pmd_t *pmd,
2361
                int write_access, pte_t orig_pte)
2362
{
2363
        pgoff_t pgoff = (((address & PAGE_MASK)
2364
                        - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
2365
        unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
2366
 
2367
        pte_unmap(page_table);
2368
        return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
2369
}
2370
 
2371
 
2372
/*
2373
 * do_no_pfn() tries to create a new page mapping for a page without
2374
 * a struct_page backing it
2375
 *
2376
 * As this is called only for pages that do not currently exist, we
2377
 * do not need to flush old virtual caches or the TLB.
2378
 *
2379
 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2380
 * but allow concurrent faults), and pte mapped but not yet locked.
2381
 * We return with mmap_sem still held, but pte unmapped and unlocked.
2382
 *
2383
 * It is expected that the ->nopfn handler always returns the same pfn
2384
 * for a given virtual mapping.
2385
 *
2386
 * Mark this `noinline' to prevent it from bloating the main pagefault code.
2387
 */
2388
static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma,
2389
                     unsigned long address, pte_t *page_table, pmd_t *pmd,
2390
                     int write_access)
2391
{
2392
        spinlock_t *ptl;
2393
        pte_t entry;
2394
        unsigned long pfn;
2395
 
2396
        pte_unmap(page_table);
2397
        BUG_ON(!(vma->vm_flags & VM_PFNMAP));
2398
        BUG_ON(is_cow_mapping(vma->vm_flags));
2399
 
2400
        pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK);
2401
        if (unlikely(pfn == NOPFN_OOM))
2402
                return VM_FAULT_OOM;
2403
        else if (unlikely(pfn == NOPFN_SIGBUS))
2404
                return VM_FAULT_SIGBUS;
2405
        else if (unlikely(pfn == NOPFN_REFAULT))
2406
                return 0;
2407
 
2408
        page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2409
 
2410
        /* Only go through if we didn't race with anybody else... */
2411
        if (pte_none(*page_table)) {
2412
                entry = pfn_pte(pfn, vma->vm_page_prot);
2413
                if (write_access)
2414
                        entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2415
                set_pte_at(mm, address, page_table, entry);
2416
        }
2417
        pte_unmap_unlock(page_table, ptl);
2418
        return 0;
2419
}
2420
 
2421
/*
2422
 * Fault of a previously existing named mapping. Repopulate the pte
2423
 * from the encoded file_pte if possible. This enables swappable
2424
 * nonlinear vmas.
2425
 *
2426
 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2427
 * but allow concurrent faults), and pte mapped but not yet locked.
2428
 * We return with mmap_sem still held, but pte unmapped and unlocked.
2429
 */
2430
static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2431
                unsigned long address, pte_t *page_table, pmd_t *pmd,
2432
                int write_access, pte_t orig_pte)
2433
{
2434
        unsigned int flags = FAULT_FLAG_NONLINEAR |
2435
                                (write_access ? FAULT_FLAG_WRITE : 0);
2436
        pgoff_t pgoff;
2437
 
2438
        if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2439
                return 0;
2440
 
2441
        if (unlikely(!(vma->vm_flags & VM_NONLINEAR) ||
2442
                        !(vma->vm_flags & VM_CAN_NONLINEAR))) {
2443
                /*
2444
                 * Page table corrupted: show pte and kill process.
2445
                 */
2446
                print_bad_pte(vma, orig_pte, address);
2447
                return VM_FAULT_OOM;
2448
        }
2449
 
2450
        pgoff = pte_to_pgoff(orig_pte);
2451
        return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
2452
}
2453
 
2454
/*
2455
 * These routines also need to handle stuff like marking pages dirty
2456
 * and/or accessed for architectures that don't do it in hardware (most
2457
 * RISC architectures).  The early dirtying is also good on the i386.
2458
 *
2459
 * There is also a hook called "update_mmu_cache()" that architectures
2460
 * with external mmu caches can use to update those (ie the Sparc or
2461
 * PowerPC hashed page tables that act as extended TLBs).
2462
 *
2463
 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2464
 * but allow concurrent faults), and pte mapped but not yet locked.
2465
 * We return with mmap_sem still held, but pte unmapped and unlocked.
2466
 */
2467
static inline int handle_pte_fault(struct mm_struct *mm,
2468
                struct vm_area_struct *vma, unsigned long address,
2469
                pte_t *pte, pmd_t *pmd, int write_access)
2470
{
2471
        pte_t entry;
2472
        spinlock_t *ptl;
2473
 
2474
        entry = *pte;
2475
        if (!pte_present(entry)) {
2476
                if (pte_none(entry)) {
2477
                        if (vma->vm_ops) {
2478
                                if (vma->vm_ops->fault || vma->vm_ops->nopage)
2479
                                        return do_linear_fault(mm, vma, address,
2480
                                                pte, pmd, write_access, entry);
2481
                                if (unlikely(vma->vm_ops->nopfn))
2482
                                        return do_no_pfn(mm, vma, address, pte,
2483
                                                         pmd, write_access);
2484
                        }
2485
                        return do_anonymous_page(mm, vma, address,
2486
                                                 pte, pmd, write_access);
2487
                }
2488
                if (pte_file(entry))
2489
                        return do_nonlinear_fault(mm, vma, address,
2490
                                        pte, pmd, write_access, entry);
2491
                return do_swap_page(mm, vma, address,
2492
                                        pte, pmd, write_access, entry);
2493
        }
2494
 
2495
        ptl = pte_lockptr(mm, pmd);
2496
        spin_lock(ptl);
2497
        if (unlikely(!pte_same(*pte, entry)))
2498
                goto unlock;
2499
        if (write_access) {
2500
                if (!pte_write(entry))
2501
                        return do_wp_page(mm, vma, address,
2502
                                        pte, pmd, ptl, entry);
2503
                entry = pte_mkdirty(entry);
2504
        }
2505
        entry = pte_mkyoung(entry);
2506
        if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
2507
                update_mmu_cache(vma, address, entry);
2508
        } else {
2509
                /*
2510
                 * This is needed only for protection faults but the arch code
2511
                 * is not yet telling us if this is a protection fault or not.
2512
                 * This still avoids useless tlb flushes for .text page faults
2513
                 * with threads.
2514
                 */
2515
                if (write_access)
2516
                        flush_tlb_page(vma, address);
2517
        }
2518
unlock:
2519
        pte_unmap_unlock(pte, ptl);
2520
        return 0;
2521
}
2522
 
2523
/*
2524
 * By the time we get here, we already hold the mm semaphore
2525
 */
2526
int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2527
                unsigned long address, int write_access)
2528
{
2529
        pgd_t *pgd;
2530
        pud_t *pud;
2531
        pmd_t *pmd;
2532
        pte_t *pte;
2533
 
2534
        __set_current_state(TASK_RUNNING);
2535
 
2536
        count_vm_event(PGFAULT);
2537
 
2538
        if (unlikely(is_vm_hugetlb_page(vma)))
2539
                return hugetlb_fault(mm, vma, address, write_access);
2540
 
2541
        pgd = pgd_offset(mm, address);
2542
        pud = pud_alloc(mm, pgd, address);
2543
        if (!pud)
2544
                return VM_FAULT_OOM;
2545
        pmd = pmd_alloc(mm, pud, address);
2546
        if (!pmd)
2547
                return VM_FAULT_OOM;
2548
        pte = pte_alloc_map(mm, pmd, address);
2549
        if (!pte)
2550
                return VM_FAULT_OOM;
2551
 
2552
        return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
2553
}
2554
 
2555
#ifndef __PAGETABLE_PUD_FOLDED
2556
/*
2557
 * Allocate page upper directory.
2558
 * We've already handled the fast-path in-line.
2559
 */
2560
int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2561
{
2562
        pud_t *new = pud_alloc_one(mm, address);
2563
        if (!new)
2564
                return -ENOMEM;
2565
 
2566
        spin_lock(&mm->page_table_lock);
2567
        if (pgd_present(*pgd))          /* Another has populated it */
2568
                pud_free(new);
2569
        else
2570
                pgd_populate(mm, pgd, new);
2571
        spin_unlock(&mm->page_table_lock);
2572
        return 0;
2573
}
2574
#endif /* __PAGETABLE_PUD_FOLDED */
2575
 
2576
#ifndef __PAGETABLE_PMD_FOLDED
2577
/*
2578
 * Allocate page middle directory.
2579
 * We've already handled the fast-path in-line.
2580
 */
2581
int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2582
{
2583
        pmd_t *new = pmd_alloc_one(mm, address);
2584
        if (!new)
2585
                return -ENOMEM;
2586
 
2587
        spin_lock(&mm->page_table_lock);
2588
#ifndef __ARCH_HAS_4LEVEL_HACK
2589
        if (pud_present(*pud))          /* Another has populated it */
2590
                pmd_free(new);
2591
        else
2592
                pud_populate(mm, pud, new);
2593
#else
2594
        if (pgd_present(*pud))          /* Another has populated it */
2595
                pmd_free(new);
2596
        else
2597
                pgd_populate(mm, pud, new);
2598
#endif /* __ARCH_HAS_4LEVEL_HACK */
2599
        spin_unlock(&mm->page_table_lock);
2600
        return 0;
2601
}
2602
#endif /* __PAGETABLE_PMD_FOLDED */
2603
 
2604
int make_pages_present(unsigned long addr, unsigned long end)
2605
{
2606
        int ret, len, write;
2607
        struct vm_area_struct * vma;
2608
 
2609
        vma = find_vma(current->mm, addr);
2610
        if (!vma)
2611
                return -1;
2612
        write = (vma->vm_flags & VM_WRITE) != 0;
2613
        BUG_ON(addr >= end);
2614
        BUG_ON(end > vma->vm_end);
2615
        len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
2616
        ret = get_user_pages(current, current->mm, addr,
2617
                        len, write, 0, NULL, NULL);
2618
        if (ret < 0)
2619
                return ret;
2620
        return ret == len ? 0 : -1;
2621
}
2622
 
2623
/*
2624
 * Map a vmalloc()-space virtual address to the physical page.
2625
 */
2626
struct page * vmalloc_to_page(void * vmalloc_addr)
2627
{
2628
        unsigned long addr = (unsigned long) vmalloc_addr;
2629
        struct page *page = NULL;
2630
        pgd_t *pgd = pgd_offset_k(addr);
2631
        pud_t *pud;
2632
        pmd_t *pmd;
2633
        pte_t *ptep, pte;
2634
 
2635
        if (!pgd_none(*pgd)) {
2636
                pud = pud_offset(pgd, addr);
2637
                if (!pud_none(*pud)) {
2638
                        pmd = pmd_offset(pud, addr);
2639
                        if (!pmd_none(*pmd)) {
2640
                                ptep = pte_offset_map(pmd, addr);
2641
                                pte = *ptep;
2642
                                if (pte_present(pte))
2643
                                        page = pte_page(pte);
2644
                                pte_unmap(ptep);
2645
                        }
2646
                }
2647
        }
2648
        return page;
2649
}
2650
 
2651
EXPORT_SYMBOL(vmalloc_to_page);
2652
 
2653
/*
2654
 * Map a vmalloc()-space virtual address to the physical page frame number.
2655
 */
2656
unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2657
{
2658
        return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2659
}
2660
 
2661
EXPORT_SYMBOL(vmalloc_to_pfn);
2662
 
2663
#if !defined(__HAVE_ARCH_GATE_AREA)
2664
 
2665
#if defined(AT_SYSINFO_EHDR)
2666
static struct vm_area_struct gate_vma;
2667
 
2668
static int __init gate_vma_init(void)
2669
{
2670
        gate_vma.vm_mm = NULL;
2671
        gate_vma.vm_start = FIXADDR_USER_START;
2672
        gate_vma.vm_end = FIXADDR_USER_END;
2673
        gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
2674
        gate_vma.vm_page_prot = __P101;
2675
        /*
2676
         * Make sure the vDSO gets into every core dump.
2677
         * Dumping its contents makes post-mortem fully interpretable later
2678
         * without matching up the same kernel and hardware config to see
2679
         * what PC values meant.
2680
         */
2681
        gate_vma.vm_flags |= VM_ALWAYSDUMP;
2682
        return 0;
2683
}
2684
__initcall(gate_vma_init);
2685
#endif
2686
 
2687
struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2688
{
2689
#ifdef AT_SYSINFO_EHDR
2690
        return &gate_vma;
2691
#else
2692
        return NULL;
2693
#endif
2694
}
2695
 
2696
int in_gate_area_no_task(unsigned long addr)
2697
{
2698
#ifdef AT_SYSINFO_EHDR
2699
        if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2700
                return 1;
2701
#endif
2702
        return 0;
2703
}
2704
 
2705
#endif  /* __HAVE_ARCH_GATE_AREA */
2706
 
2707
/*
2708
 * Access another process' address space.
2709
 * Source/target buffer must be kernel space,
2710
 * Do not walk the page table directly, use get_user_pages
2711
 */
2712
int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2713
{
2714
        struct mm_struct *mm;
2715
        struct vm_area_struct *vma;
2716
        struct page *page;
2717
        void *old_buf = buf;
2718
 
2719
        mm = get_task_mm(tsk);
2720
        if (!mm)
2721
                return 0;
2722
 
2723
        down_read(&mm->mmap_sem);
2724
        /* ignore errors, just check how much was successfully transferred */
2725
        while (len) {
2726
                int bytes, ret, offset;
2727
                void *maddr;
2728
 
2729
                ret = get_user_pages(tsk, mm, addr, 1,
2730
                                write, 1, &page, &vma);
2731
                if (ret <= 0)
2732
                        break;
2733
 
2734
                bytes = len;
2735
                offset = addr & (PAGE_SIZE-1);
2736
                if (bytes > PAGE_SIZE-offset)
2737
                        bytes = PAGE_SIZE-offset;
2738
 
2739
                maddr = kmap(page);
2740
                if (write) {
2741
                        copy_to_user_page(vma, page, addr,
2742
                                          maddr + offset, buf, bytes);
2743
                        set_page_dirty_lock(page);
2744
                } else {
2745
                        copy_from_user_page(vma, page, addr,
2746
                                            buf, maddr + offset, bytes);
2747
                }
2748
                kunmap(page);
2749
                page_cache_release(page);
2750
                len -= bytes;
2751
                buf += bytes;
2752
                addr += bytes;
2753
        }
2754
        up_read(&mm->mmap_sem);
2755
        mmput(mm);
2756
 
2757
        return buf - old_buf;
2758
}

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.