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CommitLineData
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1#include <linux/mm.h>
2#include <linux/highmem.h>
3#include <linux/sched.h>
d33b9f45 4#include <linux/hugetlb.h>
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5
6static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
2165009b 7 struct mm_walk *walk)
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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);
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15 if (err)
16 break;
556637cd
JW
17 addr += PAGE_SIZE;
18 if (addr == end)
19 break;
20 pte++;
21 }
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22
23 pte_unmap(pte);
24 return err;
25}
26
27static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
2165009b 28 struct mm_walk *walk)
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29{
30 pmd_t *pmd;
31 unsigned long next;
32 int err = 0;
33
34 pmd = pmd_offset(pud, addr);
35 do {
03319327 36again:
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);
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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
61 split_huge_page_pmd(walk->mm, 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);
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65 if (err)
66 break;
67 } while (pmd++, addr = next, addr != end);
68
69 return err;
70}
71
72static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
2165009b 73 struct mm_walk *walk)
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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);
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85 if (err)
86 break;
87 continue;
88 }
89 if (walk->pud_entry)
2165009b 90 err = walk->pud_entry(pud, addr, next, walk);
e6473092 91 if (!err && (walk->pmd_entry || walk->pte_entry))
2165009b 92 err = walk_pmd_range(pud, addr, next, walk);
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93 if (err)
94 break;
95 } while (pud++, addr = next, addr != end);
96
97 return err;
98}
99
116354d1
NH
100#ifdef CONFIG_HUGETLB_PAGE
101static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
102 unsigned long end)
103{
104 unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
105 return boundary < end ? boundary : end;
106}
107
108static int walk_hugetlb_range(struct vm_area_struct *vma,
109 unsigned long addr, unsigned long end,
110 struct mm_walk *walk)
111{
112 struct hstate *h = hstate_vma(vma);
113 unsigned long next;
114 unsigned long hmask = huge_page_mask(h);
115 pte_t *pte;
116 int err = 0;
117
118 do {
119 next = hugetlb_entry_end(h, addr, end);
120 pte = huge_pte_offset(walk->mm, addr & hmask);
121 if (pte && walk->hugetlb_entry)
122 err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
123 if (err)
124 return err;
125 } while (addr = next, addr != end);
126
127 return 0;
128}
6c6d5280
KM
129
130static struct vm_area_struct* hugetlb_vma(unsigned long addr, struct mm_walk *walk)
131{
132 struct vm_area_struct *vma;
133
134 /* We don't need vma lookup at all. */
135 if (!walk->hugetlb_entry)
136 return NULL;
137
138 VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem));
139 vma = find_vma(walk->mm, addr);
140 if (vma && vma->vm_start <= addr && is_vm_hugetlb_page(vma))
141 return vma;
142
143 return NULL;
144}
145
146#else /* CONFIG_HUGETLB_PAGE */
147static struct vm_area_struct* hugetlb_vma(unsigned long addr, struct mm_walk *walk)
148{
149 return NULL;
150}
151
152static int walk_hugetlb_range(struct vm_area_struct *vma,
153 unsigned long addr, unsigned long end,
154 struct mm_walk *walk)
155{
156 return 0;
157}
158
159#endif /* CONFIG_HUGETLB_PAGE */
160
161
116354d1 162
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163/**
164 * walk_page_range - walk a memory map's page tables with a callback
7682486b
RD
165 * @addr: starting address
166 * @end: ending address
167 * @walk: set of callbacks to invoke for each level of the tree
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168 *
169 * Recursively walk the page table for the memory area in a VMA,
170 * calling supplied callbacks. Callbacks are called in-order (first
171 * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
172 * etc.). If lower-level callbacks are omitted, walking depth is reduced.
173 *
2165009b
DH
174 * Each callback receives an entry pointer and the start and end of the
175 * associated range, and a copy of the original mm_walk for access to
176 * the ->private or ->mm fields.
e6473092 177 *
dd78553b
KM
178 * Usually no locks are taken, but splitting transparent huge page may
179 * take page table lock. And the bottom level iterator will map PTE
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180 * directories from highmem if necessary.
181 *
182 * If any callback returns a non-zero value, the walk is aborted and
183 * the return value is propagated back to the caller. Otherwise 0 is returned.
c27fe4c8
KM
184 *
185 * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry
186 * is !NULL.
e6473092 187 */
2165009b
DH
188int walk_page_range(unsigned long addr, unsigned long end,
189 struct mm_walk *walk)
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190{
191 pgd_t *pgd;
192 unsigned long next;
193 int err = 0;
194
195 if (addr >= end)
196 return err;
197
2165009b
DH
198 if (!walk->mm)
199 return -EINVAL;
200
201 pgd = pgd_offset(walk->mm, addr);
e6473092 202 do {
6c6d5280 203 struct vm_area_struct *vma;
5f0af70a 204
e6473092 205 next = pgd_addr_end(addr, end);
d33b9f45 206
5dc37642
NH
207 /*
208 * handle hugetlb vma individually because pagetable walk for
209 * the hugetlb page is dependent on the architecture and
210 * we can't handled it in the same manner as non-huge pages.
211 */
6c6d5280
KM
212 vma = hugetlb_vma(addr, walk);
213 if (vma) {
d33b9f45
NH
214 if (vma->vm_end < next)
215 next = vma->vm_end;
116354d1
NH
216 /*
217 * Hugepage is very tightly coupled with vma, so
218 * walk through hugetlb entries within a given vma.
219 */
220 err = walk_hugetlb_range(vma, addr, next, walk);
5dc37642
NH
221 if (err)
222 break;
116354d1 223 pgd = pgd_offset(walk->mm, next);
d33b9f45
NH
224 continue;
225 }
6c6d5280 226
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227 if (pgd_none_or_clear_bad(pgd)) {
228 if (walk->pte_hole)
2165009b 229 err = walk->pte_hole(addr, next, walk);
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230 if (err)
231 break;
d33b9f45 232 pgd++;
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233 continue;
234 }
235 if (walk->pgd_entry)
2165009b 236 err = walk->pgd_entry(pgd, addr, next, walk);
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MM
237 if (!err &&
238 (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
2165009b 239 err = walk_pud_range(pgd, addr, next, walk);
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240 if (err)
241 break;
d33b9f45
NH
242 pgd++;
243 } while (addr = next, addr != end);
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244
245 return err;
246}