8b1a2ce21ee53f3a6ea598759faf02c21c4c5dd2
[linux-3.10.git] / mm / pagewalk.c
1 #include <linux/mm.h>
2 #include <linux/highmem.h>
3 #include <linux/sched.h>
4 #include <linux/hugetlb.h>
5
6 static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
7                           struct mm_walk *walk)
8 {
9         pte_t *pte;
10         int err = 0;
11
12         pte = pte_offset_map(pmd, addr);
13         for (;;) {
14                 err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
15                 if (err)
16                        break;
17                 addr += PAGE_SIZE;
18                 if (addr == end)
19                         break;
20                 pte++;
21         }
22
23         pte_unmap(pte);
24         return err;
25 }
26
27 static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
28                           struct mm_walk *walk)
29 {
30         pmd_t *pmd;
31         unsigned long next;
32         int err = 0;
33
34         pmd = pmd_offset(pud, addr);
35         do {
36                 next = pmd_addr_end(addr, end);
37                 if (pmd_none_or_clear_bad(pmd)) {
38                         if (walk->pte_hole)
39                                 err = walk->pte_hole(addr, next, walk);
40                         if (err)
41                                 break;
42                         continue;
43                 }
44                 if (walk->pmd_entry)
45                         err = walk->pmd_entry(pmd, addr, next, walk);
46                 if (!err && walk->pte_entry)
47                         err = walk_pte_range(pmd, addr, next, walk);
48                 if (err)
49                         break;
50         } while (pmd++, addr = next, addr != end);
51
52         return err;
53 }
54
55 static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
56                           struct mm_walk *walk)
57 {
58         pud_t *pud;
59         unsigned long next;
60         int err = 0;
61
62         pud = pud_offset(pgd, addr);
63         do {
64                 next = pud_addr_end(addr, end);
65                 if (pud_none_or_clear_bad(pud)) {
66                         if (walk->pte_hole)
67                                 err = walk->pte_hole(addr, next, walk);
68                         if (err)
69                                 break;
70                         continue;
71                 }
72                 if (walk->pud_entry)
73                         err = walk->pud_entry(pud, addr, next, walk);
74                 if (!err && (walk->pmd_entry || walk->pte_entry))
75                         err = walk_pmd_range(pud, addr, next, walk);
76                 if (err)
77                         break;
78         } while (pud++, addr = next, addr != end);
79
80         return err;
81 }
82
83 #ifdef CONFIG_HUGETLB_PAGE
84 static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
85                                        unsigned long end)
86 {
87         unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
88         return boundary < end ? boundary : end;
89 }
90
91 static int walk_hugetlb_range(struct vm_area_struct *vma,
92                               unsigned long addr, unsigned long end,
93                               struct mm_walk *walk)
94 {
95         struct hstate *h = hstate_vma(vma);
96         unsigned long next;
97         unsigned long hmask = huge_page_mask(h);
98         pte_t *pte;
99         int err = 0;
100
101         do {
102                 next = hugetlb_entry_end(h, addr, end);
103                 pte = huge_pte_offset(walk->mm, addr & hmask);
104                 if (pte && walk->hugetlb_entry)
105                         err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
106                 if (err)
107                         return err;
108         } while (addr = next, addr != end);
109
110         return 0;
111 }
112 #endif
113
114 /**
115  * walk_page_range - walk a memory map's page tables with a callback
116  * @mm: memory map to walk
117  * @addr: starting address
118  * @end: ending address
119  * @walk: set of callbacks to invoke for each level of the tree
120  *
121  * Recursively walk the page table for the memory area in a VMA,
122  * calling supplied callbacks. Callbacks are called in-order (first
123  * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
124  * etc.). If lower-level callbacks are omitted, walking depth is reduced.
125  *
126  * Each callback receives an entry pointer and the start and end of the
127  * associated range, and a copy of the original mm_walk for access to
128  * the ->private or ->mm fields.
129  *
130  * No locks are taken, but the bottom level iterator will map PTE
131  * directories from highmem if necessary.
132  *
133  * If any callback returns a non-zero value, the walk is aborted and
134  * the return value is propagated back to the caller. Otherwise 0 is returned.
135  */
136 int walk_page_range(unsigned long addr, unsigned long end,
137                     struct mm_walk *walk)
138 {
139         pgd_t *pgd;
140         unsigned long next;
141         int err = 0;
142         struct vm_area_struct *vma;
143
144         if (addr >= end)
145                 return err;
146
147         if (!walk->mm)
148                 return -EINVAL;
149
150         pgd = pgd_offset(walk->mm, addr);
151         do {
152                 next = pgd_addr_end(addr, end);
153
154                 /*
155                  * handle hugetlb vma individually because pagetable walk for
156                  * the hugetlb page is dependent on the architecture and
157                  * we can't handled it in the same manner as non-huge pages.
158                  */
159                 vma = find_vma(walk->mm, addr);
160 #ifdef CONFIG_HUGETLB_PAGE
161                 if (vma && is_vm_hugetlb_page(vma)) {
162                         if (vma->vm_end < next)
163                                 next = vma->vm_end;
164                         /*
165                          * Hugepage is very tightly coupled with vma, so
166                          * walk through hugetlb entries within a given vma.
167                          */
168                         err = walk_hugetlb_range(vma, addr, next, walk);
169                         if (err)
170                                 break;
171                         pgd = pgd_offset(walk->mm, next);
172                         continue;
173                 }
174 #endif
175                 if (pgd_none_or_clear_bad(pgd)) {
176                         if (walk->pte_hole)
177                                 err = walk->pte_hole(addr, next, walk);
178                         if (err)
179                                 break;
180                         pgd++;
181                         continue;
182                 }
183                 if (walk->pgd_entry)
184                         err = walk->pgd_entry(pgd, addr, next, walk);
185                 if (!err &&
186                     (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
187                         err = walk_pud_range(pgd, addr, next, walk);
188                 if (err)
189                         break;
190                 pgd++;
191         } while (addr = next, addr != end);
192
193         return err;
194 }