arch/riscv/mm/kasan_init.c

   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 start is aligned on PGDIR_SIZE whereas the end
  22  * region is not and then we have to go down to the PUD level.
  23  */
  24
  25 static pgd_t tmp_pg_dir[PTRS_PER_PGD] __page_aligned_bss;
  26 static p4d_t tmp_p4d[PTRS_PER_P4D] __page_aligned_bss;
  27 static pud_t tmp_pud[PTRS_PER_PUD] __page_aligned_bss;
  28
  29 static void __init kasan_populate_pte(pmd_t *pmd, unsigned long vaddr, unsigned long end)
  30 {
  31         phys_addr_t phys_addr;
  32         pte_t *ptep, *p;
  33
  34         if (pmd_none(*pmd)) {
  35                 p = memblock_alloc(PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
  36                 set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(p)), PAGE_TABLE));
  37         }
  38
  39         ptep = pte_offset_kernel(pmd, vaddr);
  40
  41         do {
  42                 if (pte_none(*ptep)) {
  43                         phys_addr = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
  44                         set_pte(ptep, pfn_pte(PFN_DOWN(phys_addr), PAGE_KERNEL));
  45                         memset(__va(phys_addr), KASAN_SHADOW_INIT, PAGE_SIZE);
  46                 }
  47         } while (ptep++, vaddr += PAGE_SIZE, vaddr != end);
  48 }
  49
  50 static void __init kasan_populate_pmd(pud_t *pud, unsigned long vaddr, unsigned long end)
  51 {
  52         phys_addr_t phys_addr;
  53         pmd_t *pmdp, *p;
  54         unsigned long next;
  55
  56         if (pud_none(*pud)) {
  57                 p = memblock_alloc(PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
  58                 set_pud(pud, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
  59         }
  60
  61         pmdp = pmd_offset(pud, vaddr);
  62
  63         do {
  64                 next = pmd_addr_end(vaddr, end);
  65
  66                 if (pmd_none(*pmdp) && IS_ALIGNED(vaddr, PMD_SIZE) && (next - vaddr) >= PMD_SIZE) {
  67                         phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE);
  68                         if (phys_addr) {
  69                                 set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL));
  70                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, PMD_SIZE);
  71                                 continue;
  72                         }
  73                 }
  74
  75                 kasan_populate_pte(pmdp, vaddr, next);
  76         } while (pmdp++, vaddr = next, vaddr != end);
  77 }
  78
  79 static void __init kasan_populate_pud(p4d_t *p4d,
  80                                       unsigned long vaddr, unsigned long end)
  81 {
  82         phys_addr_t phys_addr;
  83         pud_t *pudp, *p;
  84         unsigned long next;
  85
  86         if (p4d_none(*p4d)) {
  87                 p = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
  88                 set_p4d(p4d, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
  89         }
  90
  91         pudp = pud_offset(p4d, vaddr);
  92
  93         do {
  94                 next = pud_addr_end(vaddr, end);
  95
  96                 if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
  97                         phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
  98                         if (phys_addr) {
  99                                 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
 100                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, PUD_SIZE);
 101                                 continue;
 102                         }
 103                 }
 104
 105                 kasan_populate_pmd(pudp, vaddr, next);
 106         } while (pudp++, vaddr = next, vaddr != end);
 107 }
 108
 109 static void __init kasan_populate_p4d(pgd_t *pgd,
 110                                       unsigned long vaddr, unsigned long end)
 111 {
 112         phys_addr_t phys_addr;
 113         p4d_t *p4dp, *p;
 114         unsigned long next;
 115
 116         if (pgd_none(*pgd)) {
 117                 p = memblock_alloc(PTRS_PER_P4D * sizeof(p4d_t), PAGE_SIZE);
 118                 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
 119         }
 120
 121         p4dp = p4d_offset(pgd, vaddr);
 122
 123         do {
 124                 next = p4d_addr_end(vaddr, end);
 125
 126                 if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) && (next - vaddr) >= P4D_SIZE) {
 127                         phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
 128                         if (phys_addr) {
 129                                 set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
 130                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, P4D_SIZE);
 131                                 continue;
 132                         }
 133                 }
 134
 135                 kasan_populate_pud(p4dp, vaddr, next);
 136         } while (p4dp++, vaddr = next, vaddr != end);
 137 }
 138
 139 static void __init kasan_populate_pgd(pgd_t *pgdp,
 140                                       unsigned long vaddr, unsigned long end)
 141 {
 142         phys_addr_t phys_addr;
 143         unsigned long next;
 144
 145         do {
 146                 next = pgd_addr_end(vaddr, end);
 147
 148                 if (pgd_none(*pgdp) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
 149                     (next - vaddr) >= PGDIR_SIZE) {
 150                         phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
 151                         if (phys_addr) {
 152                                 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL));
 153                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, PGDIR_SIZE);
 154                                 continue;
 155                         }
 156                 }
 157
 158                 kasan_populate_p4d(pgdp, vaddr, next);
 159         } while (pgdp++, vaddr = next, vaddr != end);
 160 }
 161
 162 static void __init kasan_early_clear_pud(p4d_t *p4dp,
 163                                          unsigned long vaddr, unsigned long end)
 164 {
 165         pud_t *pudp, *base_pud;
 166         unsigned long next;
 167
 168         if (!pgtable_l4_enabled) {
 169                 pudp = (pud_t *)p4dp;
 170         } else {
 171                 base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(*p4dp)));
 172                 pudp = base_pud + pud_index(vaddr);
 173         }
 174
 175         do {
 176                 next = pud_addr_end(vaddr, end);
 177
 178                 if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
 179                         pud_clear(pudp);
 180                         continue;
 181                 }
 182
 183                 BUG();
 184         } while (pudp++, vaddr = next, vaddr != end);
 185 }
 186
 187 static void __init kasan_early_clear_p4d(pgd_t *pgdp,
 188                                          unsigned long vaddr, unsigned long end)
 189 {
 190         p4d_t *p4dp, *base_p4d;
 191         unsigned long next;
 192
 193         if (!pgtable_l5_enabled) {
 194                 p4dp = (p4d_t *)pgdp;
 195         } else {
 196                 base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgdp)));
 197                 p4dp = base_p4d + p4d_index(vaddr);
 198         }
 199
 200         do {
 201                 next = p4d_addr_end(vaddr, end);
 202
 203                 if (pgtable_l4_enabled && IS_ALIGNED(vaddr, P4D_SIZE) &&
 204                     (next - vaddr) >= P4D_SIZE) {
 205                         p4d_clear(p4dp);
 206                         continue;
 207                 }
 208
 209                 kasan_early_clear_pud(p4dp, vaddr, next);
 210         } while (p4dp++, vaddr = next, vaddr != end);
 211 }
 212
 213 static void __init kasan_early_clear_pgd(pgd_t *pgdp,
 214                                          unsigned long vaddr, unsigned long end)
 215 {
 216         unsigned long next;
 217
 218         do {
 219                 next = pgd_addr_end(vaddr, end);
 220
 221                 if (pgtable_l5_enabled && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
 222                     (next - vaddr) >= PGDIR_SIZE) {
 223                         pgd_clear(pgdp);
 224                         continue;
 225                 }
 226
 227                 kasan_early_clear_p4d(pgdp, vaddr, next);
 228         } while (pgdp++, vaddr = next, vaddr != end);
 229 }
 230
 231 static void __init kasan_early_populate_pud(p4d_t *p4dp,
 232                                             unsigned long vaddr,
 233                                             unsigned long end)
 234 {
 235         pud_t *pudp, *base_pud;
 236         phys_addr_t phys_addr;
 237         unsigned long next;
 238
 239         if (!pgtable_l4_enabled) {
 240                 pudp = (pud_t *)p4dp;
 241         } else {
 242                 base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(*p4dp)));
 243                 pudp = base_pud + pud_index(vaddr);
 244         }
 245
 246         do {
 247                 next = pud_addr_end(vaddr, end);
 248
 249                 if (pud_none(*pudp) && IS_ALIGNED(vaddr, PUD_SIZE) &&
 250                     (next - vaddr) >= PUD_SIZE) {
 251                         phys_addr = __pa((uintptr_t)kasan_early_shadow_pmd);
 252                         set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
 253                         continue;
 254                 }
 255
 256                 BUG();
 257         } while (pudp++, vaddr = next, vaddr != end);
 258 }
 259
 260 static void __init kasan_early_populate_p4d(pgd_t *pgdp,
 261                                             unsigned long vaddr,
 262                                             unsigned long end)
 263 {
 264         p4d_t *p4dp, *base_p4d;
 265         phys_addr_t phys_addr;
 266         unsigned long next;
 267
 268         /*
 269          * We can't use pgd_page_vaddr here as it would return a linear
 270          * mapping address but it is not mapped yet, but when populating
 271          * early_pg_dir, we need the physical address and when populating
 272          * swapper_pg_dir, we need the kernel virtual address so use
 273          * pt_ops facility.
 274          * Note that this test is then completely equivalent to
 275          * p4dp = p4d_offset(pgdp, vaddr)
 276          */
 277         if (!pgtable_l5_enabled) {
 278                 p4dp = (p4d_t *)pgdp;
 279         } else {
 280                 base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(*pgdp)));
 281                 p4dp = base_p4d + p4d_index(vaddr);
 282         }
 283
 284         do {
 285                 next = p4d_addr_end(vaddr, end);
 286
 287                 if (p4d_none(*p4dp) && IS_ALIGNED(vaddr, P4D_SIZE) &&
 288                     (next - vaddr) >= P4D_SIZE) {
 289                         phys_addr = __pa((uintptr_t)kasan_early_shadow_pud);
 290                         set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));
 291                         continue;
 292                 }
 293
 294                 kasan_early_populate_pud(p4dp, vaddr, next);
 295         } while (p4dp++, vaddr = next, vaddr != end);
 296 }
 297
 298 static void __init kasan_early_populate_pgd(pgd_t *pgdp,
 299                                             unsigned long vaddr,
 300                                             unsigned long end)
 301 {
 302         phys_addr_t phys_addr;
 303         unsigned long next;
 304
 305         do {
 306                 next = pgd_addr_end(vaddr, end);
 307
 308                 if (pgd_none(*pgdp) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
 309                     (next - vaddr) >= PGDIR_SIZE) {
 310                         phys_addr = __pa((uintptr_t)kasan_early_shadow_p4d);
 311                         set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
 312                         continue;
 313                 }
 314
 315                 kasan_early_populate_p4d(pgdp, vaddr, next);
 316         } while (pgdp++, vaddr = next, vaddr != end);
 317 }
 318
 319 asmlinkage void __init kasan_early_init(void)
 320 {
 321         uintptr_t i;
 322
 323         BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
 324                 KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
 325
 326         for (i = 0; i < PTRS_PER_PTE; ++i)
 327                 set_pte(kasan_early_shadow_pte + i,
 328                         pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL));
 329
 330         for (i = 0; i < PTRS_PER_PMD; ++i)
 331                 set_pmd(kasan_early_shadow_pmd + i,
 332                         pfn_pmd(PFN_DOWN
 333                                 (__pa((uintptr_t)kasan_early_shadow_pte)),
 334                                 PAGE_TABLE));
 335
 336         if (pgtable_l4_enabled) {
 337                 for (i = 0; i < PTRS_PER_PUD; ++i)
 338                         set_pud(kasan_early_shadow_pud + i,
 339                                 pfn_pud(PFN_DOWN
 340                                         (__pa(((uintptr_t)kasan_early_shadow_pmd))),
 341                                         PAGE_TABLE));
 342         }
 343
 344         if (pgtable_l5_enabled) {
 345                 for (i = 0; i < PTRS_PER_P4D; ++i)
 346                         set_p4d(kasan_early_shadow_p4d + i,
 347                                 pfn_p4d(PFN_DOWN
 348                                         (__pa(((uintptr_t)kasan_early_shadow_pud))),
 349                                         PAGE_TABLE));
 350         }
 351
 352         kasan_early_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),
 353                                  KASAN_SHADOW_START, KASAN_SHADOW_END);
 354
 355         local_flush_tlb_all();
 356 }
 357
 358 void __init kasan_swapper_init(void)
 359 {
 360         kasan_early_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),
 361                                  KASAN_SHADOW_START, KASAN_SHADOW_END);
 362
 363         local_flush_tlb_all();
 364 }
 365
 366 static void __init kasan_populate(void *start, void *end)
 367 {
 368         unsigned long vaddr = (unsigned long)start & PAGE_MASK;
 369         unsigned long vend = PAGE_ALIGN((unsigned long)end);
 370
 371         kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend);
 372 }
 373
 374 static void __init kasan_shallow_populate_pud(p4d_t *p4d,
 375                                               unsigned long vaddr, unsigned long end)
 376 {
 377         unsigned long next;
 378         void *p;
 379         pud_t *pud_k = pud_offset(p4d, vaddr);
 380
 381         do {
 382                 next = pud_addr_end(vaddr, end);
 383
 384                 if (pud_none(*pud_k)) {
 385                         p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 386                         set_pud(pud_k, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
 387                         continue;
 388                 }
 389
 390                 BUG();
 391         } while (pud_k++, vaddr = next, vaddr != end);
 392 }
 393
 394 static void __init kasan_shallow_populate_p4d(pgd_t *pgd,
 395                                               unsigned long vaddr, unsigned long end)
 396 {
 397         unsigned long next;
 398         void *p;
 399         p4d_t *p4d_k = p4d_offset(pgd, vaddr);
 400
 401         do {
 402                 next = p4d_addr_end(vaddr, end);
 403
 404                 if (p4d_none(*p4d_k)) {
 405                         p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 406                         set_p4d(p4d_k, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
 407                         continue;
 408                 }
 409
 410                 kasan_shallow_populate_pud(p4d_k, vaddr, end);
 411         } while (p4d_k++, vaddr = next, vaddr != end);
 412 }
 413
 414 static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
 415 {
 416         unsigned long next;
 417         void *p;
 418         pgd_t *pgd_k = pgd_offset_k(vaddr);
 419
 420         do {
 421                 next = pgd_addr_end(vaddr, end);
 422
 423                 if (pgd_none(*pgd_k)) {
 424                         p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 425                         set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
 426                         continue;
 427                 }
 428
 429                 kasan_shallow_populate_p4d(pgd_k, vaddr, next);
 430         } while (pgd_k++, vaddr = next, vaddr != end);
 431 }
 432
 433 static void __init kasan_shallow_populate(void *start, void *end)
 434 {
 435         unsigned long vaddr = (unsigned long)start & PAGE_MASK;
 436         unsigned long vend = PAGE_ALIGN((unsigned long)end);
 437
 438         kasan_shallow_populate_pgd(vaddr, vend);
 439 }
 440
 441 static void __init create_tmp_mapping(void)
 442 {
 443         void *ptr;
 444         p4d_t *base_p4d;
 445
 446         /*
 447          * We need to clean the early mapping: this is hard to achieve "in-place",
 448          * so install a temporary mapping like arm64 and x86 do.
 449          */
 450         memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(pgd_t) * PTRS_PER_PGD);
 451
 452         /* Copy the last p4d since it is shared with the kernel mapping. */
 453         if (pgtable_l5_enabled) {
 454                 ptr = (p4d_t *)pgd_page_vaddr(*pgd_offset_k(KASAN_SHADOW_END));
 455                 memcpy(tmp_p4d, ptr, sizeof(p4d_t) * PTRS_PER_P4D);
 456                 set_pgd(&tmp_pg_dir[pgd_index(KASAN_SHADOW_END)],
 457                         pfn_pgd(PFN_DOWN(__pa(tmp_p4d)), PAGE_TABLE));
 458                 base_p4d = tmp_p4d;
 459         } else {
 460                 base_p4d = (p4d_t *)tmp_pg_dir;
 461         }
 462
 463         /* Copy the last pud since it is shared with the kernel mapping. */
 464         if (pgtable_l4_enabled) {
 465                 ptr = (pud_t *)p4d_page_vaddr(*(base_p4d + p4d_index(KASAN_SHADOW_END)));
 466                 memcpy(tmp_pud, ptr, sizeof(pud_t) * PTRS_PER_PUD);
 467                 set_p4d(&base_p4d[p4d_index(KASAN_SHADOW_END)],
 468                         pfn_p4d(PFN_DOWN(__pa(tmp_pud)), PAGE_TABLE));
 469         }
 470 }
 471
 472 void __init kasan_init(void)
 473 {
 474         phys_addr_t p_start, p_end;
 475         u64 i;
 476
 477         create_tmp_mapping();
 478         csr_write(CSR_SATP, PFN_DOWN(__pa(tmp_pg_dir)) | satp_mode);
 479
 480         kasan_early_clear_pgd(pgd_offset_k(KASAN_SHADOW_START),
 481                               KASAN_SHADOW_START, KASAN_SHADOW_END);
 482
 483         kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)FIXADDR_START),
 484                                     (void *)kasan_mem_to_shadow((void *)VMALLOC_START));
 485
 486         if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
 487                 kasan_shallow_populate(
 488                         (void *)kasan_mem_to_shadow((void *)VMALLOC_START),
 489                         (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
 490                 /* Shallow populate modules and BPF which are vmalloc-allocated */
 491                 kasan_shallow_populate(
 492                         (void *)kasan_mem_to_shadow((void *)MODULES_VADDR),
 493                         (void *)kasan_mem_to_shadow((void *)MODULES_END));
 494         } else {
 495                 kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)VMALLOC_START),
 496                                             (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
 497         }
 498
 499         /* Populate the linear mapping */
 500         for_each_mem_range(i, &p_start, &p_end) {
 501                 void *start = (void *)__va(p_start);
 502                 void *end = (void *)__va(p_end);
 503
 504                 if (start >= end)
 505                         break;
 506
 507                 kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
 508         }
 509
 510         /* Populate kernel */
 511         kasan_populate(kasan_mem_to_shadow((const void *)MODULES_END),
 512                        kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G));
 513
 514         for (i = 0; i < PTRS_PER_PTE; i++)
 515                 set_pte(&kasan_early_shadow_pte[i],
 516                         mk_pte(virt_to_page(kasan_early_shadow_page),
 517                                __pgprot(_PAGE_PRESENT | _PAGE_READ |
 518                                         _PAGE_ACCESSED)));
 519
 520         memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
 521         init_task.kasan_depth = 0;
 522
 523         csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | satp_mode);
 524         local_flush_tlb_all();
 525 }