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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | ||
3 | #include <linux/pagewalk.h> | |
565474af | 4 | #include <linux/debugfs.h> |
30d621f6 SP |
5 | #include <linux/ptdump.h> |
6 | #include <linux/kasan.h> | |
7 | ||
0fea6e9a | 8 | #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) |
30d621f6 SP |
9 | /* |
10 | * This is an optimization for KASAN=y case. Since all kasan page tables | |
11 | * eventually point to the kasan_early_shadow_page we could call note_page() | |
12 | * right away without walking through lower level page tables. This saves | |
13 | * us dozens of seconds (minutes for 5-level config) while checking for | |
14 | * W+X mapping or reading kernel_page_tables debugfs file. | |
15 | */ | |
16 | static inline int note_kasan_page_table(struct mm_walk *walk, | |
17 | unsigned long addr) | |
18 | { | |
19 | struct ptdump_state *st = walk->private; | |
20 | ||
f8f0d0b6 | 21 | st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0])); |
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22 | |
23 | walk->action = ACTION_CONTINUE; | |
24 | ||
25 | return 0; | |
26 | } | |
27 | #endif | |
28 | ||
29 | static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, | |
30 | unsigned long next, struct mm_walk *walk) | |
31 | { | |
32 | struct ptdump_state *st = walk->private; | |
33 | pgd_t val = READ_ONCE(*pgd); | |
34 | ||
0fea6e9a AK |
35 | #if CONFIG_PGTABLE_LEVELS > 4 && \ |
36 | (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) | |
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37 | if (pgd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_p4d))) |
38 | return note_kasan_page_table(walk, addr); | |
39 | #endif | |
40 | ||
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41 | if (st->effective_prot) |
42 | st->effective_prot(st, 0, pgd_val(val)); | |
43 | ||
d8d55f56 | 44 | if (pgd_leaf(val)) { |
f8f0d0b6 | 45 | st->note_page(st, addr, 0, pgd_val(val)); |
d8d55f56 MS |
46 | walk->action = ACTION_CONTINUE; |
47 | } | |
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48 | |
49 | return 0; | |
50 | } | |
51 | ||
52 | static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, | |
53 | unsigned long next, struct mm_walk *walk) | |
54 | { | |
55 | struct ptdump_state *st = walk->private; | |
56 | p4d_t val = READ_ONCE(*p4d); | |
57 | ||
0fea6e9a AK |
58 | #if CONFIG_PGTABLE_LEVELS > 3 && \ |
59 | (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) | |
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60 | if (p4d_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pud))) |
61 | return note_kasan_page_table(walk, addr); | |
62 | #endif | |
63 | ||
1494e0c3 SP |
64 | if (st->effective_prot) |
65 | st->effective_prot(st, 1, p4d_val(val)); | |
66 | ||
d8d55f56 | 67 | if (p4d_leaf(val)) { |
f8f0d0b6 | 68 | st->note_page(st, addr, 1, p4d_val(val)); |
d8d55f56 MS |
69 | walk->action = ACTION_CONTINUE; |
70 | } | |
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71 | |
72 | return 0; | |
73 | } | |
74 | ||
75 | static int ptdump_pud_entry(pud_t *pud, unsigned long addr, | |
76 | unsigned long next, struct mm_walk *walk) | |
77 | { | |
78 | struct ptdump_state *st = walk->private; | |
79 | pud_t val = READ_ONCE(*pud); | |
80 | ||
0fea6e9a AK |
81 | #if CONFIG_PGTABLE_LEVELS > 2 && \ |
82 | (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)) | |
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83 | if (pud_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pmd))) |
84 | return note_kasan_page_table(walk, addr); | |
85 | #endif | |
86 | ||
1494e0c3 SP |
87 | if (st->effective_prot) |
88 | st->effective_prot(st, 2, pud_val(val)); | |
89 | ||
d8d55f56 | 90 | if (pud_leaf(val)) { |
f8f0d0b6 | 91 | st->note_page(st, addr, 2, pud_val(val)); |
d8d55f56 MS |
92 | walk->action = ACTION_CONTINUE; |
93 | } | |
30d621f6 SP |
94 | |
95 | return 0; | |
96 | } | |
97 | ||
98 | static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, | |
99 | unsigned long next, struct mm_walk *walk) | |
100 | { | |
101 | struct ptdump_state *st = walk->private; | |
102 | pmd_t val = READ_ONCE(*pmd); | |
103 | ||
0fea6e9a | 104 | #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) |
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105 | if (pmd_page(val) == virt_to_page(lm_alias(kasan_early_shadow_pte))) |
106 | return note_kasan_page_table(walk, addr); | |
107 | #endif | |
108 | ||
1494e0c3 SP |
109 | if (st->effective_prot) |
110 | st->effective_prot(st, 3, pmd_val(val)); | |
d8d55f56 | 111 | if (pmd_leaf(val)) { |
f8f0d0b6 | 112 | st->note_page(st, addr, 3, pmd_val(val)); |
d8d55f56 MS |
113 | walk->action = ACTION_CONTINUE; |
114 | } | |
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115 | |
116 | return 0; | |
117 | } | |
118 | ||
119 | static int ptdump_pte_entry(pte_t *pte, unsigned long addr, | |
120 | unsigned long next, struct mm_walk *walk) | |
121 | { | |
122 | struct ptdump_state *st = walk->private; | |
426931e7 | 123 | pte_t val = ptep_get_lockless(pte); |
1494e0c3 SP |
124 | |
125 | if (st->effective_prot) | |
126 | st->effective_prot(st, 4, pte_val(val)); | |
30d621f6 | 127 | |
1494e0c3 | 128 | st->note_page(st, addr, 4, pte_val(val)); |
30d621f6 SP |
129 | |
130 | return 0; | |
131 | } | |
132 | ||
133 | static int ptdump_hole(unsigned long addr, unsigned long next, | |
134 | int depth, struct mm_walk *walk) | |
135 | { | |
136 | struct ptdump_state *st = walk->private; | |
137 | ||
f8f0d0b6 | 138 | st->note_page(st, addr, depth, 0); |
30d621f6 SP |
139 | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static const struct mm_walk_ops ptdump_ops = { | |
144 | .pgd_entry = ptdump_pgd_entry, | |
145 | .p4d_entry = ptdump_p4d_entry, | |
146 | .pud_entry = ptdump_pud_entry, | |
147 | .pmd_entry = ptdump_pmd_entry, | |
148 | .pte_entry = ptdump_pte_entry, | |
149 | .pte_hole = ptdump_hole, | |
150 | }; | |
151 | ||
e47690d7 | 152 | void ptdump_walk_pgd(struct ptdump_state *st, struct mm_struct *mm, pgd_t *pgd) |
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153 | { |
154 | const struct ptdump_range *range = st->range; | |
155 | ||
8782fb61 | 156 | mmap_write_lock(mm); |
30d621f6 SP |
157 | while (range->start != range->end) { |
158 | walk_page_range_novma(mm, range->start, range->end, | |
e47690d7 | 159 | &ptdump_ops, pgd, st); |
30d621f6 SP |
160 | range++; |
161 | } | |
8782fb61 | 162 | mmap_write_unlock(mm); |
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163 | |
164 | /* Flush out the last page */ | |
f8f0d0b6 | 165 | st->note_page(st, 0, -1, 0); |
30d621f6 | 166 | } |
565474af CL |
167 | |
168 | static int check_wx_show(struct seq_file *m, void *v) | |
169 | { | |
170 | if (ptdump_check_wx()) | |
171 | seq_puts(m, "SUCCESS\n"); | |
172 | else | |
173 | seq_puts(m, "FAILED\n"); | |
174 | ||
175 | return 0; | |
176 | } | |
177 | ||
178 | DEFINE_SHOW_ATTRIBUTE(check_wx); | |
179 | ||
180 | static int ptdump_debugfs_init(void) | |
181 | { | |
182 | debugfs_create_file("check_wx_pages", 0400, NULL, NULL, &check_wx_fops); | |
183 | ||
184 | return 0; | |
185 | } | |
186 | ||
187 | device_initcall(ptdump_debugfs_init); |