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 if (pgd_none(*pgd)) { 115 base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE); 116 memcpy(base_pud, (void *)kasan_early_shadow_pud, 117 sizeof(pud_t) * PTRS_PER_PUD); 118 } else { 119 base_pud = (pud_t *)pgd_page_vaddr(*pgd); 120 if (base_pud == lm_alias(kasan_early_shadow_pud)) { 121 base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE); 122 memcpy(base_pud, (void *)kasan_early_shadow_pud, 123 sizeof(pud_t) * PTRS_PER_PUD); 124 } 125 } 126 127 pudp = base_pud + pud_index(vaddr); 128 129 do { 130 next = pud_addr_end(vaddr, end); 131 132 if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) { 133 if (early) { 134 phys_addr = __pa(((uintptr_t)kasan_early_shadow_pmd)); 135 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE)); 136 continue; 137 } else { 138 phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE); 139 if (phys_addr) { 140 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL)); 141 continue; 142 } 143 } 144 } 145 146 kasan_populate_pmd(pudp, vaddr, next); 147 } while (pudp++, vaddr = next, vaddr != end); 148 149 /* 150 * Wait for the whole PGD to be populated before setting the PGD in 151 * the page table, otherwise, if we did set the PGD before populating 152 * it entirely, memblock could allocate a page at a physical address 153 * where KASAN is not populated yet and then we'd get a page fault. 154 */ 155 if (!early) 156 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_pud)), PAGE_TABLE)); 157 } 158 159 static void __init kasan_populate_p4d(pgd_t *pgd, 160 unsigned long vaddr, unsigned long end, 161 bool early) 162 { 163 phys_addr_t phys_addr; 164 p4d_t *p4dp, *base_p4d; 165 unsigned long next; 166 167 if (early) { 168 /* 169 * We can't use pgd_page_vaddr here as it would return a linear 170 * mapping address but it is not mapped yet, but when populating 171 * early_pg_dir, we need the physical address and when populating 172 * swapper_pg_dir, we need the kernel virtual address so use 173 * pt_ops facility. 174 */ 175 base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgd))); 176 } else { 177 base_p4d = (p4d_t *)pgd_page_vaddr(*pgd); 178 if (base_p4d == lm_alias(kasan_early_shadow_p4d)) { 179 base_p4d = memblock_alloc(PTRS_PER_PUD * sizeof(p4d_t), PAGE_SIZE); 180 memcpy(base_p4d, (void *)kasan_early_shadow_p4d, 181 sizeof(p4d_t) * PTRS_PER_P4D); 182 } 183 } 184 185 p4dp = base_p4d + p4d_index(vaddr); 186 187 do { 188 next = p4d_addr_end(vaddr, end); 189 190 if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) { 191 if (early) { 192 phys_addr = __pa(((uintptr_t)kasan_early_shadow_pud)); 193 set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE)); 194 continue; 195 } else { 196 phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE); 197 if (phys_addr) { 198 set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL)); 199 continue; 200 } 201 } 202 } 203 204 kasan_populate_pud((pgd_t *)p4dp, vaddr, next, early); 205 } while (p4dp++, vaddr = next, vaddr != end); 206 207 /* 208 * Wait for the whole P4D to be populated before setting the P4D in 209 * the page table, otherwise, if we did set the P4D before populating 210 * it entirely, memblock could allocate a page at a physical address 211 * where KASAN is not populated yet and then we'd get a page fault. 212 */ 213 if (!early) 214 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(base_p4d)), PAGE_TABLE)); 215 } 216 217 #define kasan_early_shadow_pgd_next (pgtable_l5_enabled ? \ 218 (uintptr_t)kasan_early_shadow_p4d : \ 219 (pgtable_l4_enabled ? \ 220 (uintptr_t)kasan_early_shadow_pud : \ 221 (uintptr_t)kasan_early_shadow_pmd)) 222 #define kasan_populate_pgd_next(pgdp, vaddr, next, early) \ 223 (pgtable_l5_enabled ? \ 224 kasan_populate_p4d(pgdp, vaddr, next, early) : \ 225 (pgtable_l4_enabled ? \ 226 kasan_populate_pud(pgdp, vaddr, next, early) : \ 227 kasan_populate_pmd((pud_t *)pgdp, vaddr, next))) 228 229 static void __init kasan_populate_pgd(pgd_t *pgdp, 230 unsigned long vaddr, unsigned long end, 231 bool early) 232 { 233 phys_addr_t phys_addr; 234 unsigned long next; 235 236 do { 237 next = pgd_addr_end(vaddr, end); 238 239 if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) { 240 if (early) { 241 phys_addr = __pa((uintptr_t)kasan_early_shadow_pgd_next); 242 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE)); 243 continue; 244 } else if (pgd_page_vaddr(*pgdp) == 245 (unsigned long)lm_alias(kasan_early_shadow_pgd_next)) { 246 /* 247 * pgdp can't be none since kasan_early_init 248 * initialized all KASAN shadow region with 249 * kasan_early_shadow_pud: if this is still the 250 * case, that means we can try to allocate a 251 * hugepage as a replacement. 252 */ 253 phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE); 254 if (phys_addr) { 255 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL)); 256 continue; 257 } 258 } 259 } 260 261 kasan_populate_pgd_next(pgdp, vaddr, next, early); 262 } while (pgdp++, vaddr = next, vaddr != end); 263 } 264 265 asmlinkage void __init kasan_early_init(void) 266 { 267 uintptr_t i; 268 269 BUILD_BUG_ON(KASAN_SHADOW_OFFSET != 270 KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT))); 271 272 for (i = 0; i < PTRS_PER_PTE; ++i) 273 set_pte(kasan_early_shadow_pte + i, 274 pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL)); 275 276 for (i = 0; i < PTRS_PER_PMD; ++i) 277 set_pmd(kasan_early_shadow_pmd + i, 278 pfn_pmd(PFN_DOWN 279 (__pa((uintptr_t)kasan_early_shadow_pte)), 280 PAGE_TABLE)); 281 282 if (pgtable_l4_enabled) { 283 for (i = 0; i < PTRS_PER_PUD; ++i) 284 set_pud(kasan_early_shadow_pud + i, 285 pfn_pud(PFN_DOWN 286 (__pa(((uintptr_t)kasan_early_shadow_pmd))), 287 PAGE_TABLE)); 288 } 289 290 if (pgtable_l5_enabled) { 291 for (i = 0; i < PTRS_PER_P4D; ++i) 292 set_p4d(kasan_early_shadow_p4d + i, 293 pfn_p4d(PFN_DOWN 294 (__pa(((uintptr_t)kasan_early_shadow_pud))), 295 PAGE_TABLE)); 296 } 297 298 kasan_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START), 299 KASAN_SHADOW_START, KASAN_SHADOW_END, true); 300 301 local_flush_tlb_all(); 302 } 303 304 void __init kasan_swapper_init(void) 305 { 306 kasan_populate_pgd(pgd_offset_k(KASAN_SHADOW_START), 307 KASAN_SHADOW_START, KASAN_SHADOW_END, true); 308 309 local_flush_tlb_all(); 310 } 311 312 static void __init kasan_populate(void *start, void *end) 313 { 314 unsigned long vaddr = (unsigned long)start & PAGE_MASK; 315 unsigned long vend = PAGE_ALIGN((unsigned long)end); 316 317 kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend, false); 318 319 local_flush_tlb_all(); 320 memset(start, KASAN_SHADOW_INIT, end - start); 321 } 322 323 static void __init kasan_shallow_populate_pmd(pgd_t *pgdp, 324 unsigned long vaddr, unsigned long end) 325 { 326 unsigned long next; 327 pmd_t *pmdp, *base_pmd; 328 bool is_kasan_pte; 329 330 base_pmd = (pmd_t *)pgd_page_vaddr(*pgdp); 331 pmdp = base_pmd + pmd_index(vaddr); 332 333 do { 334 next = pmd_addr_end(vaddr, end); 335 is_kasan_pte = (pmd_pgtable(*pmdp) == lm_alias(kasan_early_shadow_pte)); 336 337 if (is_kasan_pte) 338 pmd_clear(pmdp); 339 } while (pmdp++, vaddr = next, vaddr != end); 340 } 341 342 static void __init kasan_shallow_populate_pud(pgd_t *pgdp, 343 unsigned long vaddr, unsigned long end) 344 { 345 unsigned long next; 346 pud_t *pudp, *base_pud; 347 pmd_t *base_pmd; 348 bool is_kasan_pmd; 349 350 base_pud = (pud_t *)pgd_page_vaddr(*pgdp); 351 pudp = base_pud + pud_index(vaddr); 352 353 do { 354 next = pud_addr_end(vaddr, end); 355 is_kasan_pmd = (pud_pgtable(*pudp) == lm_alias(kasan_early_shadow_pmd)); 356 357 if (!is_kasan_pmd) 358 continue; 359 360 base_pmd = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 361 set_pud(pudp, pfn_pud(PFN_DOWN(__pa(base_pmd)), PAGE_TABLE)); 362 363 if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) 364 continue; 365 366 memcpy(base_pmd, (void *)kasan_early_shadow_pmd, PAGE_SIZE); 367 kasan_shallow_populate_pmd((pgd_t *)pudp, vaddr, next); 368 } while (pudp++, vaddr = next, vaddr != end); 369 } 370 371 static void __init kasan_shallow_populate_p4d(pgd_t *pgdp, 372 unsigned long vaddr, unsigned long end) 373 { 374 unsigned long next; 375 p4d_t *p4dp, *base_p4d; 376 pud_t *base_pud; 377 bool is_kasan_pud; 378 379 base_p4d = (p4d_t *)pgd_page_vaddr(*pgdp); 380 p4dp = base_p4d + p4d_index(vaddr); 381 382 do { 383 next = p4d_addr_end(vaddr, end); 384 is_kasan_pud = (p4d_pgtable(*p4dp) == lm_alias(kasan_early_shadow_pud)); 385 386 if (!is_kasan_pud) 387 continue; 388 389 base_pud = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 390 set_p4d(p4dp, pfn_p4d(PFN_DOWN(__pa(base_pud)), PAGE_TABLE)); 391 392 if (IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) 393 continue; 394 395 memcpy(base_pud, (void *)kasan_early_shadow_pud, PAGE_SIZE); 396 kasan_shallow_populate_pud((pgd_t *)p4dp, vaddr, next); 397 } while (p4dp++, vaddr = next, vaddr != end); 398 } 399 400 #define kasan_shallow_populate_pgd_next(pgdp, vaddr, next) \ 401 (pgtable_l5_enabled ? \ 402 kasan_shallow_populate_p4d(pgdp, vaddr, next) : \ 403 (pgtable_l4_enabled ? \ 404 kasan_shallow_populate_pud(pgdp, vaddr, next) : \ 405 kasan_shallow_populate_pmd(pgdp, vaddr, next))) 406 407 static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end) 408 { 409 unsigned long next; 410 void *p; 411 pgd_t *pgd_k = pgd_offset_k(vaddr); 412 bool is_kasan_pgd_next; 413 414 do { 415 next = pgd_addr_end(vaddr, end); 416 is_kasan_pgd_next = (pgd_page_vaddr(*pgd_k) == 417 (unsigned long)lm_alias(kasan_early_shadow_pgd_next)); 418 419 if (is_kasan_pgd_next) { 420 p = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 421 set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE)); 422 } 423 424 if (IS_ALIGNED(vaddr, PGDIR_SIZE) && (next - vaddr) >= PGDIR_SIZE) 425 continue; 426 427 memcpy(p, (void *)kasan_early_shadow_pgd_next, PAGE_SIZE); 428 kasan_shallow_populate_pgd_next(pgd_k, vaddr, next); 429 } while (pgd_k++, vaddr = next, vaddr != end); 430 } 431 432 static void __init kasan_shallow_populate(void *start, void *end) 433 { 434 unsigned long vaddr = (unsigned long)start & PAGE_MASK; 435 unsigned long vend = PAGE_ALIGN((unsigned long)end); 436 437 kasan_shallow_populate_pgd(vaddr, vend); 438 local_flush_tlb_all(); 439 } 440 441 void __init kasan_init(void) 442 { 443 phys_addr_t p_start, p_end; 444 u64 i; 445 446 if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) 447 kasan_shallow_populate( 448 (void *)kasan_mem_to_shadow((void *)VMALLOC_START), 449 (void *)kasan_mem_to_shadow((void *)VMALLOC_END)); 450 451 /* Populate the linear mapping */ 452 for_each_mem_range(i, &p_start, &p_end) { 453 void *start = (void *)__va(p_start); 454 void *end = (void *)__va(p_end); 455 456 if (start >= end) 457 break; 458 459 kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end)); 460 } 461 462 /* Populate kernel, BPF, modules mapping */ 463 kasan_populate(kasan_mem_to_shadow((const void *)MODULES_VADDR), 464 kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G)); 465 466 for (i = 0; i < PTRS_PER_PTE; i++) 467 set_pte(&kasan_early_shadow_pte[i], 468 mk_pte(virt_to_page(kasan_early_shadow_page), 469 __pgprot(_PAGE_PRESENT | _PAGE_READ | 470 _PAGE_ACCESSED))); 471 472 memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE); 473 init_task.kasan_depth = 0; 474 } 475