1 #include <linux/mm.h>
2 #include <linux/highmem.h>
3 #include <linux/sched.h>
4 #include <linux/hugetlb.h>
5
walk_pte_range(pmd_t * pmd,unsigned long addr,unsigned long end,struct mm_walk * walk)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
walk_pmd_range(pud_t * pud,unsigned long addr,unsigned long end,struct mm_walk * walk)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 again:
37 next = pmd_addr_end(addr, end);
38 if (pmd_none(*pmd)) {
39 if (walk->pte_hole)
40 err = walk->pte_hole(addr, next, walk);
41 if (err)
42 break;
43 continue;
44 }
45 /*
46 * This implies that each ->pmd_entry() handler
47 * needs to know about pmd_trans_huge() pmds
48 */
49 if (walk->pmd_entry)
50 err = walk->pmd_entry(pmd, addr, next, walk);
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);
62 if (pmd_none_or_clear_bad(pmd))
63 goto again;
64 err = walk_pte_range(pmd, addr, next, walk);
65 if (err)
66 break;
67 } while (pmd++, addr = next, addr != end);
68
69 return err;
70 }
71
walk_pud_range(pgd_t * pgd,unsigned long addr,unsigned long end,struct mm_walk * walk)72 static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
73 struct mm_walk *walk)
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)
84 err = walk->pte_hole(addr, next, walk);
85 if (err)
86 break;
87 continue;
88 }
89 if (walk->pud_entry)
90 err = walk->pud_entry(pud, addr, next, walk);
91 if (!err && (walk->pmd_entry || walk->pte_entry))
92 err = walk_pmd_range(pud, addr, next, walk);
93 if (err)
94 break;
95 } while (pud++, addr = next, addr != end);
96
97 return err;
98 }
99
100 #ifdef CONFIG_HUGETLB_PAGE
hugetlb_entry_end(struct hstate * h,unsigned long addr,unsigned long end)101 static 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
walk_hugetlb_range(struct vm_area_struct * vma,unsigned long addr,unsigned long end,struct mm_walk * walk)108 static 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 }
129 #endif
130
131 /**
132 * walk_page_range - walk a memory map's page tables with a callback
133 * @mm: memory map to walk
134 * @addr: starting address
135 * @end: ending address
136 * @walk: set of callbacks to invoke for each level of the tree
137 *
138 * Recursively walk the page table for the memory area in a VMA,
139 * calling supplied callbacks. Callbacks are called in-order (first
140 * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
141 * etc.). If lower-level callbacks are omitted, walking depth is reduced.
142 *
143 * Each callback receives an entry pointer and the start and end of the
144 * associated range, and a copy of the original mm_walk for access to
145 * the ->private or ->mm fields.
146 *
147 * No locks are taken, but the bottom level iterator will map PTE
148 * directories from highmem if necessary.
149 *
150 * If any callback returns a non-zero value, the walk is aborted and
151 * the return value is propagated back to the caller. Otherwise 0 is returned.
152 */
walk_page_range(unsigned long addr,unsigned long end,struct mm_walk * walk)153 int walk_page_range(unsigned long addr, unsigned long end,
154 struct mm_walk *walk)
155 {
156 pgd_t *pgd;
157 unsigned long next;
158 int err = 0;
159
160 if (addr >= end)
161 return err;
162
163 if (!walk->mm)
164 return -EINVAL;
165
166 pgd = pgd_offset(walk->mm, addr);
167 do {
168 struct vm_area_struct *uninitialized_var(vma);
169
170 next = pgd_addr_end(addr, end);
171
172 #ifdef CONFIG_HUGETLB_PAGE
173 /*
174 * handle hugetlb vma individually because pagetable walk for
175 * the hugetlb page is dependent on the architecture and
176 * we can't handled it in the same manner as non-huge pages.
177 */
178 vma = find_vma(walk->mm, addr);
179 if (vma && is_vm_hugetlb_page(vma)) {
180 if (vma->vm_end < next)
181 next = vma->vm_end;
182 /*
183 * Hugepage is very tightly coupled with vma, so
184 * walk through hugetlb entries within a given vma.
185 */
186 err = walk_hugetlb_range(vma, addr, next, walk);
187 if (err)
188 break;
189 pgd = pgd_offset(walk->mm, next);
190 continue;
191 }
192 #endif
193 if (pgd_none_or_clear_bad(pgd)) {
194 if (walk->pte_hole)
195 err = walk->pte_hole(addr, next, walk);
196 if (err)
197 break;
198 pgd++;
199 continue;
200 }
201 if (walk->pgd_entry)
202 err = walk->pgd_entry(pgd, addr, next, walk);
203 if (!err &&
204 (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
205 err = walk_pud_range(pgd, addr, next, walk);
206 if (err)
207 break;
208 pgd++;
209 } while (addr = next, addr != end);
210
211 return err;
212 }
213