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e6473092 MM |
1 | #include <linux/mm.h> |
2 | #include <linux/highmem.h> | |
3 | #include <linux/sched.h> | |
d33b9f45 | 4 | #include <linux/hugetlb.h> |
e6473092 MM |
5 | |
6 | static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, | |
2165009b | 7 | struct mm_walk *walk) |
e6473092 MM |
8 | { |
9 | pte_t *pte; | |
10 | int err = 0; | |
11 | ||
12 | pte = pte_offset_map(pmd, addr); | |
556637cd | 13 | for (;;) { |
2165009b | 14 | err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk); |
e6473092 MM |
15 | if (err) |
16 | break; | |
556637cd JW |
17 | addr += PAGE_SIZE; |
18 | if (addr == end) | |
19 | break; | |
20 | pte++; | |
21 | } | |
e6473092 MM |
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, | |
2165009b | 28 | struct mm_walk *walk) |
e6473092 MM |
29 | { |
30 | pmd_t *pmd; | |
31 | unsigned long next; | |
32 | int err = 0; | |
33 | ||
34 | pmd = pmd_offset(pud, addr); | |
35 | do { | |
03319327 | 36 | again: |
e6473092 | 37 | next = pmd_addr_end(addr, end); |
03319327 | 38 | if (pmd_none(*pmd)) { |
e6473092 | 39 | if (walk->pte_hole) |
2165009b | 40 | err = walk->pte_hole(addr, next, walk); |
e6473092 MM |
41 | if (err) |
42 | break; | |
43 | continue; | |
44 | } | |
03319327 DH |
45 | /* |
46 | * This implies that each ->pmd_entry() handler | |
47 | * needs to know about pmd_trans_huge() pmds | |
48 | */ | |
e6473092 | 49 | if (walk->pmd_entry) |
2165009b | 50 | err = walk->pmd_entry(pmd, addr, next, walk); |
03319327 DH |
51 | if (err) |
52 | break; | |
53 | ||
54 | /* | |
55 | * Check this here so we only break down trans_huge | |
56 | * pages when we _need_ to | |
57 | */ | |
58 | if (!walk->pte_entry) | |
59 | continue; | |
60 | ||
e180377f | 61 | split_huge_page_pmd_mm(walk->mm, addr, pmd); |
1a5a9906 | 62 | if (pmd_none_or_trans_huge_or_clear_bad(pmd)) |
03319327 DH |
63 | goto again; |
64 | err = walk_pte_range(pmd, addr, next, walk); | |
e6473092 MM |
65 | if (err) |
66 | break; | |
67 | } while (pmd++, addr = next, addr != end); | |
68 | ||
69 | return err; | |
70 | } | |
71 | ||
72 | static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end, | |
2165009b | 73 | struct mm_walk *walk) |
e6473092 MM |
74 | { |
75 | pud_t *pud; | |
76 | unsigned long next; | |
77 | int err = 0; | |
78 | ||
79 | pud = pud_offset(pgd, addr); | |
80 | do { | |
81 | next = pud_addr_end(addr, end); | |
82 | if (pud_none_or_clear_bad(pud)) { | |
83 | if (walk->pte_hole) | |
2165009b | 84 | err = walk->pte_hole(addr, next, walk); |
e6473092 MM |
85 | if (err) |
86 | break; | |
87 | continue; | |
88 | } | |
0b1fbfe5 | 89 | if (walk->pmd_entry || walk->pte_entry) |
2165009b | 90 | err = walk_pmd_range(pud, addr, next, walk); |
e6473092 MM |
91 | if (err) |
92 | break; | |
93 | } while (pud++, addr = next, addr != end); | |
94 | ||
95 | return err; | |
96 | } | |
97 | ||
116354d1 NH |
98 | #ifdef CONFIG_HUGETLB_PAGE |
99 | static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr, | |
100 | unsigned long end) | |
101 | { | |
102 | unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h); | |
103 | return boundary < end ? boundary : end; | |
104 | } | |
105 | ||
106 | static int walk_hugetlb_range(struct vm_area_struct *vma, | |
107 | unsigned long addr, unsigned long end, | |
108 | struct mm_walk *walk) | |
109 | { | |
110 | struct hstate *h = hstate_vma(vma); | |
111 | unsigned long next; | |
112 | unsigned long hmask = huge_page_mask(h); | |
113 | pte_t *pte; | |
114 | int err = 0; | |
115 | ||
116 | do { | |
117 | next = hugetlb_entry_end(h, addr, end); | |
118 | pte = huge_pte_offset(walk->mm, addr & hmask); | |
119 | if (pte && walk->hugetlb_entry) | |
120 | err = walk->hugetlb_entry(pte, hmask, addr, next, walk); | |
121 | if (err) | |
122 | return err; | |
123 | } while (addr = next, addr != end); | |
124 | ||
125 | return 0; | |
126 | } | |
6c6d5280 | 127 | |
6c6d5280 | 128 | #else /* CONFIG_HUGETLB_PAGE */ |
6c6d5280 KM |
129 | static int walk_hugetlb_range(struct vm_area_struct *vma, |
130 | unsigned long addr, unsigned long end, | |
131 | struct mm_walk *walk) | |
132 | { | |
133 | return 0; | |
134 | } | |
135 | ||
136 | #endif /* CONFIG_HUGETLB_PAGE */ | |
137 | ||
138 | ||
116354d1 | 139 | |
e6473092 MM |
140 | /** |
141 | * walk_page_range - walk a memory map's page tables with a callback | |
7682486b RD |
142 | * @addr: starting address |
143 | * @end: ending address | |
144 | * @walk: set of callbacks to invoke for each level of the tree | |
e6473092 MM |
145 | * |
146 | * Recursively walk the page table for the memory area in a VMA, | |
147 | * calling supplied callbacks. Callbacks are called in-order (first | |
148 | * PGD, first PUD, first PMD, first PTE, second PTE... second PMD, | |
149 | * etc.). If lower-level callbacks are omitted, walking depth is reduced. | |
150 | * | |
2165009b DH |
151 | * Each callback receives an entry pointer and the start and end of the |
152 | * associated range, and a copy of the original mm_walk for access to | |
153 | * the ->private or ->mm fields. | |
e6473092 | 154 | * |
dd78553b KM |
155 | * Usually no locks are taken, but splitting transparent huge page may |
156 | * take page table lock. And the bottom level iterator will map PTE | |
e6473092 MM |
157 | * directories from highmem if necessary. |
158 | * | |
159 | * If any callback returns a non-zero value, the walk is aborted and | |
160 | * the return value is propagated back to the caller. Otherwise 0 is returned. | |
c27fe4c8 KM |
161 | * |
162 | * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry | |
163 | * is !NULL. | |
e6473092 | 164 | */ |
2165009b DH |
165 | int walk_page_range(unsigned long addr, unsigned long end, |
166 | struct mm_walk *walk) | |
e6473092 MM |
167 | { |
168 | pgd_t *pgd; | |
169 | unsigned long next; | |
170 | int err = 0; | |
171 | ||
172 | if (addr >= end) | |
173 | return err; | |
174 | ||
2165009b DH |
175 | if (!walk->mm) |
176 | return -EINVAL; | |
177 | ||
96dad67f | 178 | VM_BUG_ON_MM(!rwsem_is_locked(&walk->mm->mmap_sem), walk->mm); |
a9ff785e | 179 | |
2165009b | 180 | pgd = pgd_offset(walk->mm, addr); |
e6473092 | 181 | do { |
a9ff785e | 182 | struct vm_area_struct *vma = NULL; |
5f0af70a | 183 | |
e6473092 | 184 | next = pgd_addr_end(addr, end); |
d33b9f45 | 185 | |
5dc37642 | 186 | /* |
a9ff785e CW |
187 | * This function was not intended to be vma based. |
188 | * But there are vma special cases to be handled: | |
189 | * - hugetlb vma's | |
190 | * - VM_PFNMAP vma's | |
5dc37642 | 191 | */ |
a9ff785e | 192 | vma = find_vma(walk->mm, addr); |
6c6d5280 | 193 | if (vma) { |
a9ff785e CW |
194 | /* |
195 | * There are no page structures backing a VM_PFNMAP | |
196 | * range, so do not allow split_huge_page_pmd(). | |
197 | */ | |
198 | if ((vma->vm_start <= addr) && | |
199 | (vma->vm_flags & VM_PFNMAP)) { | |
23aaed66 SH |
200 | if (walk->pte_hole) |
201 | err = walk->pte_hole(addr, next, walk); | |
202 | if (err) | |
203 | break; | |
a9ff785e CW |
204 | pgd = pgd_offset(walk->mm, next); |
205 | continue; | |
206 | } | |
116354d1 | 207 | /* |
a9ff785e CW |
208 | * Handle hugetlb vma individually because pagetable |
209 | * walk for the hugetlb page is dependent on the | |
210 | * architecture and we can't handled it in the same | |
211 | * manner as non-huge pages. | |
116354d1 | 212 | */ |
a9ff785e CW |
213 | if (walk->hugetlb_entry && (vma->vm_start <= addr) && |
214 | is_vm_hugetlb_page(vma)) { | |
215 | if (vma->vm_end < next) | |
216 | next = vma->vm_end; | |
217 | /* | |
218 | * Hugepage is very tightly coupled with vma, | |
219 | * so walk through hugetlb entries within a | |
220 | * given vma. | |
221 | */ | |
222 | err = walk_hugetlb_range(vma, addr, next, walk); | |
223 | if (err) | |
224 | break; | |
225 | pgd = pgd_offset(walk->mm, next); | |
226 | continue; | |
227 | } | |
d33b9f45 | 228 | } |
6c6d5280 | 229 | |
e6473092 MM |
230 | if (pgd_none_or_clear_bad(pgd)) { |
231 | if (walk->pte_hole) | |
2165009b | 232 | err = walk->pte_hole(addr, next, walk); |
e6473092 MM |
233 | if (err) |
234 | break; | |
d33b9f45 | 235 | pgd++; |
e6473092 MM |
236 | continue; |
237 | } | |
0b1fbfe5 | 238 | if (walk->pmd_entry || walk->pte_entry) |
2165009b | 239 | err = walk_pud_range(pgd, addr, next, walk); |
e6473092 MM |
240 | if (err) |
241 | break; | |
d33b9f45 | 242 | pgd++; |
3017f079 | 243 | } while (addr = next, addr < end); |
e6473092 MM |
244 | |
245 | return err; | |
246 | } |