1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * KASAN for 64-bit Book3e powerpc
4 *
5 * Copyright 2022, Christophe Leroy, CS GROUP France
6 */
7
8 #define DISABLE_BRANCH_PROFILING
9
10 #include <linux/kasan.h>
11 #include <linux/printk.h>
12 #include <linux/memblock.h>
13 #include <linux/set_memory.h>
14
15 #include <asm/pgalloc.h>
16
17 static inline bool kasan_pud_table(p4d_t p4d)
18 {
19 return p4d_page(p4d) == virt_to_page(lm_alias(kasan_early_shadow_pud));
20 }
21
22 static inline bool kasan_pmd_table(pud_t pud)
23 {
24 return pud_page(pud) == virt_to_page(lm_alias(kasan_early_shadow_pmd));
25 }
26
27 static inline bool kasan_pte_table(pmd_t pmd)
28 {
29 return pmd_page(pmd) == virt_to_page(lm_alias(kasan_early_shadow_pte));
30 }
31
32 static int __init kasan_map_kernel_page(unsigned long ea, unsigned long pa, pgprot_t prot)
33 {
34 pgd_t *pgdp;
35 p4d_t *p4dp;
36 pud_t *pudp;
37 pmd_t *pmdp;
38 pte_t *ptep;
39
40 pgdp = pgd_offset_k(ea);
41 p4dp = p4d_offset(pgdp, ea);
42 if (kasan_pud_table(*p4dp)) {
43 pudp = memblock_alloc(PUD_TABLE_SIZE, PUD_TABLE_SIZE);
44 memcpy(pudp, kasan_early_shadow_pud, PUD_TABLE_SIZE);
45 p4d_populate(&init_mm, p4dp, pudp);
46 }
47 pudp = pud_offset(p4dp, ea);
48 if (kasan_pmd_table(*pudp)) {
49 pmdp = memblock_alloc(PMD_TABLE_SIZE, PMD_TABLE_SIZE);
50 memcpy(pmdp, kasan_early_shadow_pmd, PMD_TABLE_SIZE);
51 pud_populate(&init_mm, pudp, pmdp);
52 }
53 pmdp = pmd_offset(pudp, ea);
54 if (kasan_pte_table(*pmdp)) {
55 ptep = memblock_alloc(PTE_TABLE_SIZE, PTE_TABLE_SIZE);
56 memcpy(ptep, kasan_early_shadow_pte, PTE_TABLE_SIZE);
57 pmd_populate_kernel(&init_mm, pmdp, ptep);
58 }
59 ptep = pte_offset_kernel(pmdp, ea);
60
61 __set_pte_at(&init_mm, ea, ptep, pfn_pte(pa >> PAGE_SHIFT, prot), 0);
62
63 return 0;
64 }
65
66 static void __init kasan_init_phys_region(void *start, void *end)
67 {
68 unsigned long k_start, k_end, k_cur;
69 void *va;
70
71 if (start >= end)
72 return;
73
74 k_start = ALIGN_DOWN((unsigned long)kasan_mem_to_shadow(start), PAGE_SIZE);
75 k_end = ALIGN((unsigned long)kasan_mem_to_shadow(end), PAGE_SIZE);
76
77 va = memblock_alloc(k_end - k_start, PAGE_SIZE);
78 for (k_cur = k_start; k_cur < k_end; k_cur += PAGE_SIZE, va += PAGE_SIZE)
79 kasan_map_kernel_page(k_cur, __pa(va), PAGE_KERNEL);
80 }
81
82 void __init kasan_early_init(void)
83 {
84 int i;
85 unsigned long addr;
86 pgd_t *pgd = pgd_offset_k(KASAN_SHADOW_START);
87 pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL);
88
89 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
90 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
91
92 for (i = 0; i < PTRS_PER_PTE; i++)
93 __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
94 &kasan_early_shadow_pte[i], zero_pte, 0);
95
96 for (i = 0; i < PTRS_PER_PMD; i++)
97 pmd_populate_kernel(&init_mm, &kasan_early_shadow_pmd[i],
98 kasan_early_shadow_pte);
99
100 for (i = 0; i < PTRS_PER_PUD; i++)
101 pud_populate(&init_mm, &kasan_early_shadow_pud[i],
102 kasan_early_shadow_pmd);
103
104 for (addr = KASAN_SHADOW_START; addr != KASAN_SHADOW_END; addr += PGDIR_SIZE)
105 p4d_populate(&init_mm, p4d_offset(pgd++, addr), kasan_early_shadow_pud);
106 }
107
108 void __init kasan_init(void)
109 {
110 phys_addr_t start, end;
111 u64 i;
112 pte_t zero_pte = pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL_RO);
113
114 for_each_mem_range(i, &start, &end)
115 kasan_init_phys_region(phys_to_virt(start), phys_to_virt(end));
116
117 if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
118 kasan_remove_zero_shadow((void *)VMALLOC_START, VMALLOC_SIZE);
119
120 for (i = 0; i < PTRS_PER_PTE; i++)
121 __set_pte_at(&init_mm, (unsigned long)kasan_early_shadow_page,
122 &kasan_early_shadow_pte[i], zero_pte, 0);
123
124 flush_tlb_kernel_range(KASAN_SHADOW_START, KASAN_SHADOW_END);
125
126 memset(kasan_early_shadow_page, 0, PAGE_SIZE);
127
128 /* Enable error messages */
129 init_task.kasan_depth = 0;
130 pr_info("KASAN init done\n");
131 }
132
133 void __init kasan_late_init(void) { }
134
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