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9#define pr_fmt(fmt) "kasan: " fmt
10#include <linux/kasan.h>
11#include <linux/kernel.h>
12#include <linux/sched/task.h>
13#include <linux/memblock.h>
14#include <linux/start_kernel.h>
15#include <linux/mm.h>
16
17#include <asm/mmu_context.h>
18#include <asm/kernel-pgtable.h>
19#include <asm/page.h>
20#include <asm/pgalloc.h>
21#include <asm/pgtable.h>
22#include <asm/sections.h>
23#include <asm/tlbflush.h>
24
25static pgd_t tmp_pg_dir[PTRS_PER_PGD] __initdata __aligned(PGD_SIZE);
26
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31
32
33
34static phys_addr_t __init kasan_alloc_zeroed_page(int node)
35{
36 void *p = memblock_alloc_try_nid(PAGE_SIZE, PAGE_SIZE,
37 __pa(MAX_DMA_ADDRESS),
38 MEMBLOCK_ALLOC_KASAN, node);
39 if (!p)
40 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
41 __func__, PAGE_SIZE, PAGE_SIZE, node,
42 __pa(MAX_DMA_ADDRESS));
43
44 return __pa(p);
45}
46
47static phys_addr_t __init kasan_alloc_raw_page(int node)
48{
49 void *p = memblock_alloc_try_nid_raw(PAGE_SIZE, PAGE_SIZE,
50 __pa(MAX_DMA_ADDRESS),
51 MEMBLOCK_ALLOC_KASAN, node);
52 if (!p)
53 panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%llx\n",
54 __func__, PAGE_SIZE, PAGE_SIZE, node,
55 __pa(MAX_DMA_ADDRESS));
56
57 return __pa(p);
58}
59
60static pte_t *__init kasan_pte_offset(pmd_t *pmdp, unsigned long addr, int node,
61 bool early)
62{
63 if (pmd_none(READ_ONCE(*pmdp))) {
64 phys_addr_t pte_phys = early ?
65 __pa_symbol(kasan_early_shadow_pte)
66 : kasan_alloc_zeroed_page(node);
67 __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
68 }
69
70 return early ? pte_offset_kimg(pmdp, addr)
71 : pte_offset_kernel(pmdp, addr);
72}
73
74static pmd_t *__init kasan_pmd_offset(pud_t *pudp, unsigned long addr, int node,
75 bool early)
76{
77 if (pud_none(READ_ONCE(*pudp))) {
78 phys_addr_t pmd_phys = early ?
79 __pa_symbol(kasan_early_shadow_pmd)
80 : kasan_alloc_zeroed_page(node);
81 __pud_populate(pudp, pmd_phys, PMD_TYPE_TABLE);
82 }
83
84 return early ? pmd_offset_kimg(pudp, addr) : pmd_offset(pudp, addr);
85}
86
87static pud_t *__init kasan_pud_offset(pgd_t *pgdp, unsigned long addr, int node,
88 bool early)
89{
90 if (pgd_none(READ_ONCE(*pgdp))) {
91 phys_addr_t pud_phys = early ?
92 __pa_symbol(kasan_early_shadow_pud)
93 : kasan_alloc_zeroed_page(node);
94 __pgd_populate(pgdp, pud_phys, PMD_TYPE_TABLE);
95 }
96
97 return early ? pud_offset_kimg(pgdp, addr) : pud_offset(pgdp, addr);
98}
99
100static void __init kasan_pte_populate(pmd_t *pmdp, unsigned long addr,
101 unsigned long end, int node, bool early)
102{
103 unsigned long next;
104 pte_t *ptep = kasan_pte_offset(pmdp, addr, node, early);
105
106 do {
107 phys_addr_t page_phys = early ?
108 __pa_symbol(kasan_early_shadow_page)
109 : kasan_alloc_raw_page(node);
110 if (!early)
111 memset(__va(page_phys), KASAN_SHADOW_INIT, PAGE_SIZE);
112 next = addr + PAGE_SIZE;
113 set_pte(ptep, pfn_pte(__phys_to_pfn(page_phys), PAGE_KERNEL));
114 } while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)));
115}
116
117static void __init kasan_pmd_populate(pud_t *pudp, unsigned long addr,
118 unsigned long end, int node, bool early)
119{
120 unsigned long next;
121 pmd_t *pmdp = kasan_pmd_offset(pudp, addr, node, early);
122
123 do {
124 next = pmd_addr_end(addr, end);
125 kasan_pte_populate(pmdp, addr, next, node, early);
126 } while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)));
127}
128
129static void __init kasan_pud_populate(pgd_t *pgdp, unsigned long addr,
130 unsigned long end, int node, bool early)
131{
132 unsigned long next;
133 pud_t *pudp = kasan_pud_offset(pgdp, addr, node, early);
134
135 do {
136 next = pud_addr_end(addr, end);
137 kasan_pmd_populate(pudp, addr, next, node, early);
138 } while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)));
139}
140
141static void __init kasan_pgd_populate(unsigned long addr, unsigned long end,
142 int node, bool early)
143{
144 unsigned long next;
145 pgd_t *pgdp;
146
147 pgdp = pgd_offset_k(addr);
148 do {
149 next = pgd_addr_end(addr, end);
150 kasan_pud_populate(pgdp, addr, next, node, early);
151 } while (pgdp++, addr = next, addr != end);
152}
153
154
155asmlinkage void __init kasan_early_init(void)
156{
157 BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
158 KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
159 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_START, PGDIR_SIZE));
160 BUILD_BUG_ON(!IS_ALIGNED(KASAN_SHADOW_END, PGDIR_SIZE));
161 kasan_pgd_populate(KASAN_SHADOW_START, KASAN_SHADOW_END, NUMA_NO_NODE,
162 true);
163}
164
165
166static void __init kasan_map_populate(unsigned long start, unsigned long end,
167 int node)
168{
169 kasan_pgd_populate(start & PAGE_MASK, PAGE_ALIGN(end), node, false);
170}
171
172
173
174
175void __init kasan_copy_shadow(pgd_t *pgdir)
176{
177 pgd_t *pgdp, *pgdp_new, *pgdp_end;
178
179 pgdp = pgd_offset_k(KASAN_SHADOW_START);
180 pgdp_end = pgd_offset_k(KASAN_SHADOW_END);
181 pgdp_new = pgd_offset_raw(pgdir, KASAN_SHADOW_START);
182 do {
183 set_pgd(pgdp_new, READ_ONCE(*pgdp));
184 } while (pgdp++, pgdp_new++, pgdp != pgdp_end);
185}
186
187static void __init clear_pgds(unsigned long start,
188 unsigned long end)
189{
190
191
192
193
194
195 for (; start < end; start += PGDIR_SIZE)
196 set_pgd(pgd_offset_k(start), __pgd(0));
197}
198
199void __init kasan_init(void)
200{
201 u64 kimg_shadow_start, kimg_shadow_end;
202 u64 mod_shadow_start, mod_shadow_end;
203 struct memblock_region *reg;
204 int i;
205
206 kimg_shadow_start = (u64)kasan_mem_to_shadow(_text) & PAGE_MASK;
207 kimg_shadow_end = PAGE_ALIGN((u64)kasan_mem_to_shadow(_end));
208
209 mod_shadow_start = (u64)kasan_mem_to_shadow((void *)MODULES_VADDR);
210 mod_shadow_end = (u64)kasan_mem_to_shadow((void *)MODULES_END);
211
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217
218
219 memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(tmp_pg_dir));
220 dsb(ishst);
221 cpu_replace_ttbr1(lm_alias(tmp_pg_dir));
222
223 clear_pgds(KASAN_SHADOW_START, KASAN_SHADOW_END);
224
225 kasan_map_populate(kimg_shadow_start, kimg_shadow_end,
226 early_pfn_to_nid(virt_to_pfn(lm_alias(_text))));
227
228 kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
229 (void *)mod_shadow_start);
230 kasan_populate_early_shadow((void *)kimg_shadow_end,
231 kasan_mem_to_shadow((void *)PAGE_OFFSET));
232
233 if (kimg_shadow_start > mod_shadow_end)
234 kasan_populate_early_shadow((void *)mod_shadow_end,
235 (void *)kimg_shadow_start);
236
237 for_each_memblock(memory, reg) {
238 void *start = (void *)__phys_to_virt(reg->base);
239 void *end = (void *)__phys_to_virt(reg->base + reg->size);
240
241 if (start >= end)
242 break;
243
244 kasan_map_populate((unsigned long)kasan_mem_to_shadow(start),
245 (unsigned long)kasan_mem_to_shadow(end),
246 early_pfn_to_nid(virt_to_pfn(start)));
247 }
248
249
250
251
252
253 for (i = 0; i < PTRS_PER_PTE; i++)
254 set_pte(&kasan_early_shadow_pte[i],
255 pfn_pte(sym_to_pfn(kasan_early_shadow_page),
256 PAGE_KERNEL_RO));
257
258 memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
259 cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
260
261
262 init_task.kasan_depth = 0;
263 pr_info("KernelAddressSanitizer initialized\n");
264}
265