1 // SPDX-License-Identifier: GPL-2.0 2 // Copyright (C) 2019 Andes Technology Corporation 3 4 #include <linux/pfn.h> 5 #include <linux/init_task.h> 6 #include <linux/kasan.h> 7 #include <linux/kernel.h> 8 #include <linux/memblock.h> 9 #include <linux/pgtable.h> 10 #include <asm/tlbflush.h> 11 #include <asm/fixmap.h> 12 #include <asm/pgalloc.h> 13 14 /* 15 * Kasan shadow region must lie at a fixed address across sv39, sv48 and sv57 16 * which is right before the kernel. 17 * 18 * For sv39, the region is aligned on PGDIR_SIZE so we only need to populate 19 * the page global directory with kasan_early_shadow_pmd. 20 * 21 * For sv48 and sv57, the region is not aligned on PGDIR_SIZE so the mapping 22 * must be divided as follows: 23 * - the first PGD entry, although incomplete, is populated with 24 * kasan_early_shadow_pud/p4d 25 * - the PGD entries in the middle are populated with kasan_early_shadow_pud/p4d 26 * - the last PGD entry is shared with the kernel mapping so populated at the 27 * lower levels pud/p4d 28 * 29 * In addition, when shallow populating a kasan region (for example vmalloc), 30 * this region may also not be aligned on PGDIR size, so we must go down to the 31 * pud level too. 32 */ 33 34 extern pgd_t early_pg_dir[PTRS_PER_PGD]; 35 36 static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end) 37 { 38 phys_addr_t phys_addr; 39 pte_t *ptep, *base_pte; 40 41 if (pmd_none(*pmd)) 42 base_pte = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE); 43 else 44 base_pte = (pte_t *)pmd_page_vaddr(*pmd); 45 46 ptep = base_pte + pte_index(vaddr); 47 48 do { 49 if (pte_none(*ptep)) { 50 phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); 51 set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL)); 52 } 53 } while (ptep++, vaddr += PAGE_SIZE, vaddr != end); 54 55 set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(base_pte)), PAGE_TABLE)); 56 } 57 58 static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end) 59 { 60 phys_addr_t phys_addr; 61 pmd_t *pmdp, *base_pmd; 62 unsigned long next; 63 64 if (pud_none(*pud)) { 65 base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE); 66 } else { 67 base_pmd = (pmd_t *)pud_pgtable(*pud); 68 if (base_pmd == lm_alias(kasan_early_shadow_pmd)) 69 base_pmd = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE); 70 } 71 72 pmdp = base_pmd + pmd_index(vaddr); 73 74 do { 75 next = pmd_addr_end(vaddr, end); 76 77 if (pmd_none(*pmdp) && IS_ALIGNED(vaddr, PMD_SIZE) && (next - vaddr) >= PMD_SIZE) { 78 phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE); 79 if (phys_addr) { 80 set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL)); 81 continue; 82 } 83 } 84 85 kasan_populate_pte(pmdp, vaddr, next); 86 } while (pmdp++, vaddr = next, vaddr != end); 87 88 /* 89 * Wait for the whole PGD to be populated before setting the PGD in 90 * the page table, otherwise, if we did set the PGD before populating 91 * it entirely, memblock could allocate a page at a physical address 92 * where KASAN is not populated yet and then we'd get a page fault. 93 */ 94 set_pud(pud, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE)); 95 } 96 97 static void __init kasan_populate_pud(pgd_t *pgd, 98 unsigned long vaddr, unsigned long end, 99 bool early) 100 { 101 phys_addr_t phys_addr; 102 pud_t *pudp, *base_pud; 103 unsigned long next; 104 105 if (early) { 106 /* 107 * We can't use pgd_page_vaddr here as it would return a linear 108 * mapping address but it is not mapped yet, but when populating 109 * early_pg_dir, we need the physical address and when populating 110 * swapper_pg_dir, we need the kernel virtual address so use 111 * pt_ops facility. 112 */ 113 base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd))); 114 } else { 115 base_pud = (pud_t *)pgd_page_vaddr(*pgd); 116 if (base_pud == lm_alias(kasan_early_shadow_pud)) 117 base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE); 118 } 119 120 pudp = base_pud + pud_index(vaddr); 121 122 do { 123 next = pud_addr_end(vaddr, end); 124 125 if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) { 126 if (early) { 127 phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd)); 128 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE)); 129 continue; 130 } else { 131 phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE); 132 if (phys_addr) { 133 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL)); 134 continue; 135 } 136 } 137 } 138 139 kasan_populate_pmd(pudp, vaddr, next); 140 } while (pudp++, vaddr = next, vaddr != end); 141 142 /* 143 * Wait for the whole PGD to be populated before setting the PGD in 144 * the page table, otherwise, if we did set the PGD before populating 145 * it entirely, memblock could allocate a page at a physical address 146 * where KASAN is not populated yet and then we'd get a page fault. 147 */ 148 if (!early) 149 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE)); 150 } 151 152 #define kasan_early_shadow_pgd_next (pgtable_l4_enabled ? \ 153 (uintptr_t)kasan_early_shadow_pud : \ 154 (uintptr_t)kasan_early_shadow_pmd) 155 #define kasan_populate_pgd_next(pgdp, vaddr, next, early) \ 156 (pgtable_l4_enabled ? \ 157 kasan_populate_pud(pgdp, vaddr, next, early) : \ 158 kasan_populate_pmd((pud_t *)pgdp, vaddr, next)) 159 160 static void __init kasan_populate_pgd(pgd_t *pgdp, 161 unsigned long vaddr, unsigned long end, 162 bool early) 163 { 164 phys_addr_t phys_addr; 165 unsigned long next; 166 167 do { 168 next = pgd_addr_end(vaddr, end); 169 170 if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) { 171 if (early) { 172 phys_addr = __pa((uintptr_t)kasan_early_shadow_pgd_next); 173 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE)); 174 continue; 175 } else if (pgd_page_vaddr(*pgdp) == 176 (unsigned long)lm_alias(kasan_early_shadow_pgd_next)) { 177 /* 178 * pgdp can't be none since kasan_early_init 179 * initialized all KASAN shadow region with 180 * kasan_early_shadow_pud: if this is still the 181 * case, that means we can try to allocate a 182 * hugepage as a replacement. 183 */ 184 phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE); 185 if (phys_addr) { 186 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL)); 187 continue; 188 } 189 } 190 } 191 192 kasan_populate_pgd_next(pgdp, vaddr, next, early); 193 } while (pgdp++, vaddr = next, vaddr != end); 194 } 195 196 asmlinkage void __init kasan_early_init(void) 197 { 198 uintptr_t i; 199 200 BUILD_BUG_ON(KASAN_SHADOW_OFFSET != 201 KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT))); 202 203 for (i = 0; i < PTRS_PER_PTE; ++i) 204 set_pte(kasan_early_shadow_pte + i, 205 mk_pte(virt_to_page(kasan_early_shadow_page), 206 PAGE_KERNEL)); 207 208 for (i = 0; i < PTRS_PER_PMD; ++i) 209 set_pmd(kasan_early_shadow_pmd + i, 210 pfn_pmd(PFN_DOWN 211 (__pa((uintptr_t)kasan_early_shadow_pte)), 212 PAGE_TABLE)); 213 214 if (pgtable_l4_enabled) { 215 for (i = 0; i < PTRS_PER_PUD; ++i) 216 set_pud(kasan_early_shadow_pud + i, 217 pfn_pud(PFN_DOWN 218 (__pa(((uintptr_t)kasan_early_shadow_pmd))), 219 PAGE_TABLE)); 220 } 221 222 kasan_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START), 223 KASAN_SHADOW_START, KASAN_SHADOW_END, true); 224 225 local_flush_tlb_all(); 226 } 227 228 void __init kasan_swapper_init(void) 229 { 230 kasan_populate_pgd(pgd_offset_k(KASAN_SHADOW_START), 231 KASAN_SHADOW_START, KASAN_SHADOW_END, true); 232 233 local_flush_tlb_all(); 234 } 235 236 static void __init kasan_populate(void *start, void *end) 237 { 238 unsigned long vaddr = (unsigned long)start & PAGE_MASK; 239 unsigned long vend = PAGE_ALIGN((unsigned long)end); 240 241 kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend, false); 242 243 local_flush_tlb_all(); 244 memset(start, KASAN_SHADOW_INIT, end - start); 245 } 246 247 static void __init kasan_shallow_populate_pud(pgd_t *pgdp, 248 unsigned long vaddr, unsigned long end, 249 bool kasan_populate) 250 { 251 unsigned long next; 252 pud_t *pudp, *base_pud; 253 pmd_t *base_pmd; 254 bool is_kasan_pmd; 255 256 base_pud = (pud_t *)pgd_page_vaddr(*pgdp); 257 pudp = base_pud + pud_index(vaddr); 258 259 if (kasan_populate) 260 memcpy(base_pud, (void *)kasan_early_shadow_pgd_next, 261 sizeof(pud_t) * PTRS_PER_PUD); 262 263 do { 264 next = pud_addr_end(vaddr, end); 265 is_kasan_pmd = (pud_pgtable(*pudp) == lm_alias(kasan_early_shadow_pmd)); 266 267 if (is_kasan_pmd) { 268 base_pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 269 set_pud(pudp, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE)); 270 } 271 } while (pudp++, vaddr = next, vaddr != end); 272 } 273 274 static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end) 275 { 276 unsigned long next; 277 void *p; 278 pgd_t *pgd_k = pgd_offset_k(vaddr); 279 bool is_kasan_pgd_next; 280 281 do { 282 next = pgd_addr_end(vaddr, end); 283 is_kasan_pgd_next = (pgd_page_vaddr(*pgd_k) == 284 (unsigned long)lm_alias(kasan_early_shadow_pgd_next)); 285 286 if (is_kasan_pgd_next) { 287 p = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 288 set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE)); 289 } 290 291 if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) 292 continue; 293 294 kasan_shallow_populate_pud(pgd_k, vaddr, next, is_kasan_pgd_next); 295 } while (pgd_k++, vaddr = next, vaddr != end); 296 } 297 298 static void __init kasan_shallow_populate(void *start, void *end) 299 { 300 unsigned long vaddr = (unsigned long)start & PAGE_MASK; 301 unsigned long vend = PAGE_ALIGN((unsigned long)end); 302 303 kasan_shallow_populate_pgd(vaddr, vend); 304 local_flush_tlb_all(); 305 } 306 307 void __init kasan_init(void) 308 { 309 phys_addr_t p_start, p_end; 310 u64 i; 311 312 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) 313 kasan_shallow_populate( 314 (void *)kasan_mem_to_shadow((void *)VMALLOC_START), 315 (void *)kasan_mem_to_shadow((void *)VMALLOC_END)); 316 317 /* Populate the linear mapping */ 318 for_each_mem_range(i, &p_start, &p_end) { 319 void *start = (void *)__va(p_start); 320 void *end = (void *)__va(p_end); 321 322 if (start >= end) 323 break; 324 325 kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end)); 326 } 327 328 /* Populate kernel, BPF, modules mapping */ 329 kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR), 330 kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G)); 331 332 for (i = 0; i < PTRS_PER_PTE; i++) 333 set_pte(&kasan_early_shadow_pte[i], 334 mk_pte(virt_to_page(kasan_early_shadow_page), 335 __pgprot(_PAGE_PRESENT | _PAGE_READ | 336 _PAGE_ACCESSED))); 337 338 memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); 339 init_task.kasan_depth = 0; 340 } 341