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(pmdp_get(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_get(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(pudp_get(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_get(pmdp)) && IS_ALIGNED(vaddr, PMD_SIZE) &&
  67                     (next - vaddr) >= PMD_SIZE) {
  68                         phys_addr = memblock_phys_alloc(PMD_SIZE, PMD_SIZE);
  69                         if (phys_addr) {
  70                                 set_pmd(pmdp, pfn_pmd(PFN_DOWN(phys_addr), PAGE_KERNEL));
  71                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, PMD_SIZE);
  72                                 continue;
  73                         }
  74                 }
  75
  76                 kasan_populate_pte(pmdp, vaddr, next);
  77         } while (pmdp++, vaddr = next, vaddr != end);
  78 }
  79
  80 static void __init kasan_populate_pud(p4d_t *p4d,
  81                                       unsigned long vaddr, unsigned long end)
  82 {
  83         phys_addr_t phys_addr;
  84         pud_t *pudp, *p;
  85         unsigned long next;
  86
  87         if (p4d_none(p4dp_get(p4d))) {
  88                 p = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
  89                 set_p4d(p4d, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
  90         }
  91
  92         pudp = pud_offset(p4d, vaddr);
  93
  94         do {
  95                 next = pud_addr_end(vaddr, end);
  96
  97                 if (pud_none(pudp_get(pudp)) && IS_ALIGNED(vaddr, PUD_SIZE) &&
  98                     (next - vaddr) >= PUD_SIZE) {
  99                         phys_addr = memblock_phys_alloc(PUD_SIZE, PUD_SIZE);
 100                         if (phys_addr) {
 101                                 set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_KERNEL));
 102                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, PUD_SIZE);
 103                                 continue;
 104                         }
 105                 }
 106
 107                 kasan_populate_pmd(pudp, vaddr, next);
 108         } while (pudp++, vaddr = next, vaddr != end);
 109 }
 110
 111 static void __init kasan_populate_p4d(pgd_t *pgd,
 112                                       unsigned long vaddr, unsigned long end)
 113 {
 114         phys_addr_t phys_addr;
 115         p4d_t *p4dp, *p;
 116         unsigned long next;
 117
 118         if (pgd_none(pgdp_get(pgd))) {
 119                 p = memblock_alloc(PTRS_PER_P4D * sizeof(p4d_t), PAGE_SIZE);
 120                 set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
 121         }
 122
 123         p4dp = p4d_offset(pgd, vaddr);
 124
 125         do {
 126                 next = p4d_addr_end(vaddr, end);
 127
 128                 if (p4d_none(p4dp_get(p4dp)) && IS_ALIGNED(vaddr, P4D_SIZE) &&
 129                     (next - vaddr) >= P4D_SIZE) {
 130                         phys_addr = memblock_phys_alloc(P4D_SIZE, P4D_SIZE);
 131                         if (phys_addr) {
 132                                 set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_KERNEL));
 133                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, P4D_SIZE);
 134                                 continue;
 135                         }
 136                 }
 137
 138                 kasan_populate_pud(p4dp, vaddr, next);
 139         } while (p4dp++, vaddr = next, vaddr != end);
 140 }
 141
 142 static void __init kasan_populate_pgd(pgd_t *pgdp,
 143                                       unsigned long vaddr, unsigned long end)
 144 {
 145         phys_addr_t phys_addr;
 146         unsigned long next;
 147
 148         do {
 149                 next = pgd_addr_end(vaddr, end);
 150
 151                 if (pgd_none(pgdp_get(pgdp)) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
 152                     (next - vaddr) >= PGDIR_SIZE) {
 153                         phys_addr = memblock_phys_alloc(PGDIR_SIZE, PGDIR_SIZE);
 154                         if (phys_addr) {
 155                                 set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_KERNEL));
 156                                 memset(__va(phys_addr), KASAN_SHADOW_INIT, PGDIR_SIZE);
 157                                 continue;
 158                         }
 159                 }
 160
 161                 kasan_populate_p4d(pgdp, vaddr, next);
 162         } while (pgdp++, vaddr = next, vaddr != end);
 163 }
 164
 165 static void __init kasan_early_clear_pud(p4d_t *p4dp,
 166                                          unsigned long vaddr, unsigned long end)
 167 {
 168         pud_t *pudp, *base_pud;
 169         unsigned long next;
 170
 171         if (!pgtable_l4_enabled) {
 172                 pudp = (pud_t *)p4dp;
 173         } else {
 174                 base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(p4dp_get(p4dp))));
 175                 pudp = base_pud + pud_index(vaddr);
 176         }
 177
 178         do {
 179                 next = pud_addr_end(vaddr, end);
 180
 181                 if (IS_ALIGNED(vaddr, PUD_SIZE) && (next - vaddr) >= PUD_SIZE) {
 182                         pud_clear(pudp);
 183                         continue;
 184                 }
 185
 186                 BUG();
 187         } while (pudp++, vaddr = next, vaddr != end);
 188 }
 189
 190 static void __init kasan_early_clear_p4d(pgd_t *pgdp,
 191                                          unsigned long vaddr, unsigned long end)
 192 {
 193         p4d_t *p4dp, *base_p4d;
 194         unsigned long next;
 195
 196         if (!pgtable_l5_enabled) {
 197                 p4dp = (p4d_t *)pgdp;
 198         } else {
 199                 base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(pgdp_get(pgdp))));
 200                 p4dp = base_p4d + p4d_index(vaddr);
 201         }
 202
 203         do {
 204                 next = p4d_addr_end(vaddr, end);
 205
 206                 if (pgtable_l4_enabled && IS_ALIGNED(vaddr, P4D_SIZE) &&
 207                     (next - vaddr) >= P4D_SIZE) {
 208                         p4d_clear(p4dp);
 209                         continue;
 210                 }
 211
 212                 kasan_early_clear_pud(p4dp, vaddr, next);
 213         } while (p4dp++, vaddr = next, vaddr != end);
 214 }
 215
 216 static void __init kasan_early_clear_pgd(pgd_t *pgdp,
 217                                          unsigned long vaddr, unsigned long end)
 218 {
 219         unsigned long next;
 220
 221         do {
 222                 next = pgd_addr_end(vaddr, end);
 223
 224                 if (pgtable_l5_enabled && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
 225                     (next - vaddr) >= PGDIR_SIZE) {
 226                         pgd_clear(pgdp);
 227                         continue;
 228                 }
 229
 230                 kasan_early_clear_p4d(pgdp, vaddr, next);
 231         } while (pgdp++, vaddr = next, vaddr != end);
 232 }
 233
 234 static void __init kasan_early_populate_pud(p4d_t *p4dp,
 235                                             unsigned long vaddr,
 236                                             unsigned long end)
 237 {
 238         pud_t *pudp, *base_pud;
 239         phys_addr_t phys_addr;
 240         unsigned long next;
 241
 242         if (!pgtable_l4_enabled) {
 243                 pudp = (pud_t *)p4dp;
 244         } else {
 245                 base_pud = pt_ops.get_pud_virt(pfn_to_phys(_p4d_pfn(p4dp_get(p4dp))));
 246                 pudp = base_pud + pud_index(vaddr);
 247         }
 248
 249         do {
 250                 next = pud_addr_end(vaddr, end);
 251
 252                 if (pud_none(pudp_get(pudp)) && IS_ALIGNED(vaddr, PUD_SIZE) &&
 253                     (next - vaddr) >= PUD_SIZE) {
 254                         phys_addr = __pa((uintptr_t)kasan_early_shadow_pmd);
 255                         set_pud(pudp, pfn_pud(PFN_DOWN(phys_addr), PAGE_TABLE));
 256                         continue;
 257                 }
 258
 259                 BUG();
 260         } while (pudp++, vaddr = next, vaddr != end);
 261 }
 262
 263 static void __init kasan_early_populate_p4d(pgd_t *pgdp,
 264                                             unsigned long vaddr,
 265                                             unsigned long end)
 266 {
 267         p4d_t *p4dp, *base_p4d;
 268         phys_addr_t phys_addr;
 269         unsigned long next;
 270
 271         /*
 272          * We can't use pgd_page_vaddr here as it would return a linear
 273          * mapping address but it is not mapped yet, but when populating
 274          * early_pg_dir, we need the physical address and when populating
 275          * swapper_pg_dir, we need the kernel virtual address so use
 276          * pt_ops facility.
 277          * Note that this test is then completely equivalent to
 278          * p4dp = p4d_offset(pgdp, vaddr)
 279          */
 280         if (!pgtable_l5_enabled) {
 281                 p4dp = (p4d_t *)pgdp;
 282         } else {
 283                 base_p4d = pt_ops.get_p4d_virt(pfn_to_phys(_pgd_pfn(pgdp_get(pgdp))));
 284                 p4dp = base_p4d + p4d_index(vaddr);
 285         }
 286
 287         do {
 288                 next = p4d_addr_end(vaddr, end);
 289
 290                 if (p4d_none(p4dp_get(p4dp)) && IS_ALIGNED(vaddr, P4D_SIZE) &&
 291                     (next - vaddr) >= P4D_SIZE) {
 292                         phys_addr = __pa((uintptr_t)kasan_early_shadow_pud);
 293                         set_p4d(p4dp, pfn_p4d(PFN_DOWN(phys_addr), PAGE_TABLE));
 294                         continue;
 295                 }
 296
 297                 kasan_early_populate_pud(p4dp, vaddr, next);
 298         } while (p4dp++, vaddr = next, vaddr != end);
 299 }
 300
 301 static void __init kasan_early_populate_pgd(pgd_t *pgdp,
 302                                             unsigned long vaddr,
 303                                             unsigned long end)
 304 {
 305         phys_addr_t phys_addr;
 306         unsigned long next;
 307
 308         do {
 309                 next = pgd_addr_end(vaddr, end);
 310
 311                 if (pgd_none(pgdp_get(pgdp)) && IS_ALIGNED(vaddr, PGDIR_SIZE) &&
 312                     (next - vaddr) >= PGDIR_SIZE) {
 313                         phys_addr = __pa((uintptr_t)kasan_early_shadow_p4d);
 314                         set_pgd(pgdp, pfn_pgd(PFN_DOWN(phys_addr), PAGE_TABLE));
 315                         continue;
 316                 }
 317
 318                 kasan_early_populate_p4d(pgdp, vaddr, next);
 319         } while (pgdp++, vaddr = next, vaddr != end);
 320 }
 321
 322 asmlinkage void __init kasan_early_init(void)
 323 {
 324         uintptr_t i;
 325
 326         BUILD_BUG_ON(KASAN_SHADOW_OFFSET !=
 327                 KASAN_SHADOW_END - (1UL << (64 - KASAN_SHADOW_SCALE_SHIFT)));
 328
 329         for (i = 0; i < PTRS_PER_PTE; ++i)
 330                 set_pte(kasan_early_shadow_pte + i,
 331                         pfn_pte(virt_to_pfn(kasan_early_shadow_page), PAGE_KERNEL));
 332
 333         for (i = 0; i < PTRS_PER_PMD; ++i)
 334                 set_pmd(kasan_early_shadow_pmd + i,
 335                         pfn_pmd(PFN_DOWN
 336                                 (__pa((uintptr_t)kasan_early_shadow_pte)),
 337                                 PAGE_TABLE));
 338
 339         if (pgtable_l4_enabled) {
 340                 for (i = 0; i < PTRS_PER_PUD; ++i)
 341                         set_pud(kasan_early_shadow_pud + i,
 342                                 pfn_pud(PFN_DOWN
 343                                         (__pa(((uintptr_t)kasan_early_shadow_pmd))),
 344                                         PAGE_TABLE));
 345         }
 346
 347         if (pgtable_l5_enabled) {
 348                 for (i = 0; i < PTRS_PER_P4D; ++i)
 349                         set_p4d(kasan_early_shadow_p4d + i,
 350                                 pfn_p4d(PFN_DOWN
 351                                         (__pa(((uintptr_t)kasan_early_shadow_pud))),
 352                                         PAGE_TABLE));
 353         }
 354
 355         kasan_early_populate_pgd(early_pg_dir + pgd_index(KASAN_SHADOW_START),
 356                                  KASAN_SHADOW_START, KASAN_SHADOW_END);
 357
 358         local_flush_tlb_all();
 359 }
 360
 361 void __init kasan_swapper_init(void)
 362 {
 363         kasan_early_populate_pgd(pgd_offset_k(KASAN_SHADOW_START),
 364                                  KASAN_SHADOW_START, KASAN_SHADOW_END);
 365
 366         local_flush_tlb_all();
 367 }
 368
 369 static void __init kasan_populate(void *start, void *end)
 370 {
 371         unsigned long vaddr = (unsigned long)start & PAGE_MASK;
 372         unsigned long vend = PAGE_ALIGN((unsigned long)end);
 373
 374         kasan_populate_pgd(pgd_offset_k(vaddr), vaddr, vend);
 375 }
 376
 377 static void __init kasan_shallow_populate_pud(p4d_t *p4d,
 378                                               unsigned long vaddr, unsigned long end)
 379 {
 380         unsigned long next;
 381         void *p;
 382         pud_t *pud_k = pud_offset(p4d, vaddr);
 383
 384         do {
 385                 next = pud_addr_end(vaddr, end);
 386
 387                 if (pud_none(pudp_get(pud_k))) {
 388                         p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 389                         set_pud(pud_k, pfn_pud(PFN_DOWN(__pa(p)), PAGE_TABLE));
 390                         continue;
 391                 }
 392
 393                 BUG();
 394         } while (pud_k++, vaddr = next, vaddr != end);
 395 }
 396
 397 static void __init kasan_shallow_populate_p4d(pgd_t *pgd,
 398                                               unsigned long vaddr, unsigned long end)
 399 {
 400         unsigned long next;
 401         void *p;
 402         p4d_t *p4d_k = p4d_offset(pgd, vaddr);
 403
 404         do {
 405                 next = p4d_addr_end(vaddr, end);
 406
 407                 if (p4d_none(p4dp_get(p4d_k))) {
 408                         p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 409                         set_p4d(p4d_k, pfn_p4d(PFN_DOWN(__pa(p)), PAGE_TABLE));
 410                         continue;
 411                 }
 412
 413                 kasan_shallow_populate_pud(p4d_k, vaddr, end);
 414         } while (p4d_k++, vaddr = next, vaddr != end);
 415 }
 416
 417 static void __init kasan_shallow_populate_pgd(unsigned long vaddr, unsigned long end)
 418 {
 419         unsigned long next;
 420         void *p;
 421         pgd_t *pgd_k = pgd_offset_k(vaddr);
 422
 423         do {
 424                 next = pgd_addr_end(vaddr, end);
 425
 426                 if (pgd_none(pgdp_get(pgd_k))) {
 427                         p = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
 428                         set_pgd(pgd_k, pfn_pgd(PFN_DOWN(__pa(p)), PAGE_TABLE));
 429                         continue;
 430                 }
 431
 432                 kasan_shallow_populate_p4d(pgd_k, vaddr, next);
 433         } while (pgd_k++, vaddr = next, vaddr != end);
 434 }
 435
 436 static void __init kasan_shallow_populate(void *start, void *end)
 437 {
 438         unsigned long vaddr = (unsigned long)start & PAGE_MASK;
 439         unsigned long vend = PAGE_ALIGN((unsigned long)end);
 440
 441         kasan_shallow_populate_pgd(vaddr, vend);
 442 }
 443
 444 #ifdef CONFIG_KASAN_VMALLOC
 445 void __init kasan_populate_early_vm_area_shadow(void *start, unsigned long size)
 446 {
 447         kasan_populate(kasan_mem_to_shadow(start),
 448                        kasan_mem_to_shadow(start + size));
 449 }
 450 #endif
 451
 452 static void __init create_tmp_mapping(void)
 453 {
 454         void *ptr;
 455         p4d_t *base_p4d;
 456
 457         /*
 458          * We need to clean the early mapping: this is hard to achieve "in-place",
 459          * so install a temporary mapping like arm64 and x86 do.
 460          */
 461         memcpy(tmp_pg_dir, swapper_pg_dir, sizeof(pgd_t) * PTRS_PER_PGD);
 462
 463         /* Copy the last p4d since it is shared with the kernel mapping. */
 464         if (pgtable_l5_enabled) {
 465                 ptr = (p4d_t *)pgd_page_vaddr(pgdp_get(pgd_offset_k(KASAN_SHADOW_END)));
 466                 memcpy(tmp_p4d, ptr, sizeof(p4d_t) * PTRS_PER_P4D);
 467                 set_pgd(&tmp_pg_dir[pgd_index(KASAN_SHADOW_END)],
 468                         pfn_pgd(PFN_DOWN(__pa(tmp_p4d)), PAGE_TABLE));
 469                 base_p4d = tmp_p4d;
 470         } else {
 471                 base_p4d = (p4d_t *)tmp_pg_dir;
 472         }
 473
 474         /* Copy the last pud since it is shared with the kernel mapping. */
 475         if (pgtable_l4_enabled) {
 476                 ptr = (pud_t *)p4d_page_vaddr(p4dp_get(base_p4d + p4d_index(KASAN_SHADOW_END)));
 477                 memcpy(tmp_pud, ptr, sizeof(pud_t) * PTRS_PER_PUD);
 478                 set_p4d(&base_p4d[p4d_index(KASAN_SHADOW_END)],
 479                         pfn_p4d(PFN_DOWN(__pa(tmp_pud)), PAGE_TABLE));
 480         }
 481 }
 482
 483 void __init kasan_init(void)
 484 {
 485         phys_addr_t p_start, p_end;
 486         u64 i;
 487
 488         create_tmp_mapping();
 489         csr_write(CSR_SATP, PFN_DOWN(__pa(tmp_pg_dir)) | satp_mode);
 490
 491         kasan_early_clear_pgd(pgd_offset_k(KASAN_SHADOW_START),
 492                               KASAN_SHADOW_START, KASAN_SHADOW_END);
 493
 494         kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)FIXADDR_START),
 495                                     (void *)kasan_mem_to_shadow((void *)VMALLOC_START));
 496
 497         if (IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
 498                 kasan_shallow_populate(
 499                         (void *)kasan_mem_to_shadow((void *)VMALLOC_START),
 500                         (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
 501                 /* Shallow populate modules and BPF which are vmalloc-allocated */
 502                 kasan_shallow_populate(
 503                         (void *)kasan_mem_to_shadow((void *)MODULES_VADDR),
 504                         (void *)kasan_mem_to_shadow((void *)MODULES_END));
 505         } else {
 506                 kasan_populate_early_shadow((void *)kasan_mem_to_shadow((void *)VMALLOC_START),
 507                                             (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
 508         }
 509
 510         /* Populate the linear mapping */
 511         for_each_mem_range(i, &p_start, &p_end) {
 512                 void *start = (void *)__va(p_start);
 513                 void *end = (void *)__va(p_end);
 514
 515                 if (start >= end)
 516                         break;
 517
 518                 kasan_populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
 519         }
 520
 521         /* Populate kernel */
 522         kasan_populate(kasan_mem_to_shadow((const void *)MODULES_END),
 523                        kasan_mem_to_shadow((const void *)MODULES_VADDR + SZ_2G));
 524
 525         for (i = 0; i < PTRS_PER_PTE; i++)
 526                 set_pte(&kasan_early_shadow_pte[i],
 527                         mk_pte(virt_to_page(kasan_early_shadow_page),
 528                                __pgprot(_PAGE_PRESENT | _PAGE_READ |
 529                                         _PAGE_ACCESSED)));
 530
 531         memset(kasan_early_shadow_page, KASAN_SHADOW_INIT, PAGE_SIZE);
 532         init_task.kasan_depth = 0;
 533
 534         csr_write(CSR_SATP, PFN_DOWN(__pa(swapper_pg_dir)) | satp_mode);
 535         local_flush_tlb_all();
 536 }