Commit | Line | Data |
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85155229 | 1 | #define pr_fmt(fmt) "kasan: " fmt |
ef7f0d6a AR |
2 | #include <linux/bootmem.h> |
3 | #include <linux/kasan.h> | |
4 | #include <linux/kdebug.h> | |
5 | #include <linux/mm.h> | |
6 | #include <linux/sched.h> | |
7 | #include <linux/vmalloc.h> | |
8 | ||
9 | #include <asm/tlbflush.h> | |
10 | #include <asm/sections.h> | |
11 | ||
12 | extern pgd_t early_level4_pgt[PTRS_PER_PGD]; | |
13 | extern struct range pfn_mapped[E820_X_MAX]; | |
14 | ||
ef7f0d6a AR |
15 | static int __init map_range(struct range *range) |
16 | { | |
17 | unsigned long start; | |
18 | unsigned long end; | |
19 | ||
20 | start = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->start)); | |
21 | end = (unsigned long)kasan_mem_to_shadow(pfn_to_kaddr(range->end)); | |
22 | ||
23 | /* | |
24 | * end + 1 here is intentional. We check several shadow bytes in advance | |
25 | * to slightly speed up fastpath. In some rare cases we could cross | |
26 | * boundary of mapped shadow, so we just map some more here. | |
27 | */ | |
28 | return vmemmap_populate(start, end + 1, NUMA_NO_NODE); | |
29 | } | |
30 | ||
31 | static void __init clear_pgds(unsigned long start, | |
32 | unsigned long end) | |
33 | { | |
34 | for (; start < end; start += PGDIR_SIZE) | |
35 | pgd_clear(pgd_offset_k(start)); | |
36 | } | |
37 | ||
5d5aa3cf | 38 | static void __init kasan_map_early_shadow(pgd_t *pgd) |
ef7f0d6a AR |
39 | { |
40 | int i; | |
41 | unsigned long start = KASAN_SHADOW_START; | |
42 | unsigned long end = KASAN_SHADOW_END; | |
43 | ||
44 | for (i = pgd_index(start); start < end; i++) { | |
45 | pgd[i] = __pgd(__pa_nodebug(kasan_zero_pud) | |
46 | | _KERNPG_TABLE); | |
47 | start += PGDIR_SIZE; | |
48 | } | |
49 | } | |
50 | ||
ef7f0d6a AR |
51 | #ifdef CONFIG_KASAN_INLINE |
52 | static int kasan_die_handler(struct notifier_block *self, | |
53 | unsigned long val, | |
54 | void *data) | |
55 | { | |
56 | if (val == DIE_GPF) { | |
2ba78056 DV |
57 | pr_emerg("CONFIG_KASAN_INLINE enabled\n"); |
58 | pr_emerg("GPF could be caused by NULL-ptr deref or user memory access\n"); | |
ef7f0d6a AR |
59 | } |
60 | return NOTIFY_OK; | |
61 | } | |
62 | ||
63 | static struct notifier_block kasan_die_notifier = { | |
64 | .notifier_call = kasan_die_handler, | |
65 | }; | |
66 | #endif | |
67 | ||
5d5aa3cf AP |
68 | void __init kasan_early_init(void) |
69 | { | |
70 | int i; | |
71 | pteval_t pte_val = __pa_nodebug(kasan_zero_page) | __PAGE_KERNEL; | |
72 | pmdval_t pmd_val = __pa_nodebug(kasan_zero_pte) | _KERNPG_TABLE; | |
73 | pudval_t pud_val = __pa_nodebug(kasan_zero_pmd) | _KERNPG_TABLE; | |
74 | ||
75 | for (i = 0; i < PTRS_PER_PTE; i++) | |
76 | kasan_zero_pte[i] = __pte(pte_val); | |
77 | ||
78 | for (i = 0; i < PTRS_PER_PMD; i++) | |
79 | kasan_zero_pmd[i] = __pmd(pmd_val); | |
80 | ||
81 | for (i = 0; i < PTRS_PER_PUD; i++) | |
82 | kasan_zero_pud[i] = __pud(pud_val); | |
83 | ||
84 | kasan_map_early_shadow(early_level4_pgt); | |
85 | kasan_map_early_shadow(init_level4_pgt); | |
86 | } | |
87 | ||
ef7f0d6a AR |
88 | void __init kasan_init(void) |
89 | { | |
90 | int i; | |
91 | ||
92 | #ifdef CONFIG_KASAN_INLINE | |
93 | register_die_notifier(&kasan_die_notifier); | |
94 | #endif | |
95 | ||
96 | memcpy(early_level4_pgt, init_level4_pgt, sizeof(early_level4_pgt)); | |
97 | load_cr3(early_level4_pgt); | |
241d2c54 | 98 | __flush_tlb_all(); |
ef7f0d6a AR |
99 | |
100 | clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END); | |
101 | ||
69786cdb | 102 | kasan_populate_zero_shadow((void *)KASAN_SHADOW_START, |
ef7f0d6a AR |
103 | kasan_mem_to_shadow((void *)PAGE_OFFSET)); |
104 | ||
105 | for (i = 0; i < E820_X_MAX; i++) { | |
106 | if (pfn_mapped[i].end == 0) | |
107 | break; | |
108 | ||
109 | if (map_range(&pfn_mapped[i])) | |
110 | panic("kasan: unable to allocate shadow!"); | |
111 | } | |
69786cdb AR |
112 | kasan_populate_zero_shadow( |
113 | kasan_mem_to_shadow((void *)PAGE_OFFSET + MAXMEM), | |
114 | kasan_mem_to_shadow((void *)__START_KERNEL_map)); | |
c420f167 AR |
115 | |
116 | vmemmap_populate((unsigned long)kasan_mem_to_shadow(_stext), | |
117 | (unsigned long)kasan_mem_to_shadow(_end), | |
118 | NUMA_NO_NODE); | |
119 | ||
69786cdb | 120 | kasan_populate_zero_shadow(kasan_mem_to_shadow((void *)MODULES_END), |
c420f167 | 121 | (void *)KASAN_SHADOW_END); |
ef7f0d6a | 122 | |
ef7f0d6a | 123 | load_cr3(init_level4_pgt); |
241d2c54 | 124 | __flush_tlb_all(); |
85155229 | 125 | |
69e0210f AR |
126 | /* |
127 | * kasan_zero_page has been used as early shadow memory, thus it may | |
063fb3e5 AR |
128 | * contain some garbage. Now we can clear and write protect it, since |
129 | * after the TLB flush no one should write to it. | |
69e0210f AR |
130 | */ |
131 | memset(kasan_zero_page, 0, PAGE_SIZE); | |
063fb3e5 AR |
132 | for (i = 0; i < PTRS_PER_PTE; i++) { |
133 | pte_t pte = __pte(__pa(kasan_zero_page) | __PAGE_KERNEL_RO); | |
134 | set_pte(&kasan_zero_pte[i], pte); | |
135 | } | |
136 | /* Flush TLBs again to be sure that write protection applied. */ | |
137 | __flush_tlb_all(); | |
69e0210f AR |
138 | |
139 | init_task.kasan_depth = 0; | |
25add7ec | 140 | pr_info("KernelAddressSanitizer initialized\n"); |
ef7f0d6a | 141 | } |