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git.ipfire.org Git - people/ms/linux.git/blob - mm/ptdump.c
1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/pagewalk.h>
4 #include <linux/ptdump.h>
5 #include <linux/kasan.h>
7 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
9 * This is an optimization for KASAN=y case. Since all kasan page tables
10 * eventually point to the kasan_early_shadow_page we could call note_page()
11 * right away without walking through lower level page tables. This saves
12 * us dozens of seconds (minutes for 5-level config) while checking for
13 * W+X mapping or reading kernel_page_tables debugfs file.
15 static inline int note_kasan_page_table(struct mm_walk
*walk
,
18 struct ptdump_state
*st
= walk
->private;
20 st
->note_page(st
, addr
, 4, pte_val(kasan_early_shadow_pte
[0]));
22 walk
->action
= ACTION_CONTINUE
;
28 static int ptdump_pgd_entry(pgd_t
*pgd
, unsigned long addr
,
29 unsigned long next
, struct mm_walk
*walk
)
31 struct ptdump_state
*st
= walk
->private;
32 pgd_t val
= READ_ONCE(*pgd
);
34 #if CONFIG_PGTABLE_LEVELS > 4 && \
35 (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
36 if (pgd_page(val
) == virt_to_page(lm_alias(kasan_early_shadow_p4d
)))
37 return note_kasan_page_table(walk
, addr
);
40 if (st
->effective_prot
)
41 st
->effective_prot(st
, 0, pgd_val(val
));
44 st
->note_page(st
, addr
, 0, pgd_val(val
));
45 walk
->action
= ACTION_CONTINUE
;
51 static int ptdump_p4d_entry(p4d_t
*p4d
, unsigned long addr
,
52 unsigned long next
, struct mm_walk
*walk
)
54 struct ptdump_state
*st
= walk
->private;
55 p4d_t val
= READ_ONCE(*p4d
);
57 #if CONFIG_PGTABLE_LEVELS > 3 && \
58 (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
59 if (p4d_page(val
) == virt_to_page(lm_alias(kasan_early_shadow_pud
)))
60 return note_kasan_page_table(walk
, addr
);
63 if (st
->effective_prot
)
64 st
->effective_prot(st
, 1, p4d_val(val
));
67 st
->note_page(st
, addr
, 1, p4d_val(val
));
68 walk
->action
= ACTION_CONTINUE
;
74 static int ptdump_pud_entry(pud_t
*pud
, unsigned long addr
,
75 unsigned long next
, struct mm_walk
*walk
)
77 struct ptdump_state
*st
= walk
->private;
78 pud_t val
= READ_ONCE(*pud
);
80 #if CONFIG_PGTABLE_LEVELS > 2 && \
81 (defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS))
82 if (pud_page(val
) == virt_to_page(lm_alias(kasan_early_shadow_pmd
)))
83 return note_kasan_page_table(walk
, addr
);
86 if (st
->effective_prot
)
87 st
->effective_prot(st
, 2, pud_val(val
));
90 st
->note_page(st
, addr
, 2, pud_val(val
));
91 walk
->action
= ACTION_CONTINUE
;
97 static int ptdump_pmd_entry(pmd_t
*pmd
, unsigned long addr
,
98 unsigned long next
, struct mm_walk
*walk
)
100 struct ptdump_state
*st
= walk
->private;
101 pmd_t val
= READ_ONCE(*pmd
);
103 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
104 if (pmd_page(val
) == virt_to_page(lm_alias(kasan_early_shadow_pte
)))
105 return note_kasan_page_table(walk
, addr
);
108 if (st
->effective_prot
)
109 st
->effective_prot(st
, 3, pmd_val(val
));
111 st
->note_page(st
, addr
, 3, pmd_val(val
));
112 walk
->action
= ACTION_CONTINUE
;
118 static int ptdump_pte_entry(pte_t
*pte
, unsigned long addr
,
119 unsigned long next
, struct mm_walk
*walk
)
121 struct ptdump_state
*st
= walk
->private;
122 pte_t val
= ptep_get(pte
);
124 if (st
->effective_prot
)
125 st
->effective_prot(st
, 4, pte_val(val
));
127 st
->note_page(st
, addr
, 4, pte_val(val
));
132 static int ptdump_hole(unsigned long addr
, unsigned long next
,
133 int depth
, struct mm_walk
*walk
)
135 struct ptdump_state
*st
= walk
->private;
137 st
->note_page(st
, addr
, depth
, 0);
142 static const struct mm_walk_ops ptdump_ops
= {
143 .pgd_entry
= ptdump_pgd_entry
,
144 .p4d_entry
= ptdump_p4d_entry
,
145 .pud_entry
= ptdump_pud_entry
,
146 .pmd_entry
= ptdump_pmd_entry
,
147 .pte_entry
= ptdump_pte_entry
,
148 .pte_hole
= ptdump_hole
,
151 void ptdump_walk_pgd(struct ptdump_state
*st
, struct mm_struct
*mm
, pgd_t
*pgd
)
153 const struct ptdump_range
*range
= st
->range
;
156 while (range
->start
!= range
->end
) {
157 walk_page_range_novma(mm
, range
->start
, range
->end
,
158 &ptdump_ops
, pgd
, st
);
161 mmap_write_unlock(mm
);
163 /* Flush out the last page */
164 st
->note_page(st
, 0, -1, 0);