개념 설명 전체 · v6.18.37 / arch/arm64/mm/mmu.c
1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Based on arch/arm/mm/mmu.c 4 * 5 * Copyright (C) 1995-2005 Russell King 6 * Copyright (C) 2012 ARM Ltd. 7 */ 8 9 #include <linux/cache.h> 10 #include <linux/export.h> 11 #include <linux/kernel.h> 12 #include <linux/errno.h> 13 #include <linux/init.h> 14 #include <linux/ioport.h> 15 #include <linux/kexec.h> 16 #include <linux/libfdt.h> 17 #include <linux/mman.h> 18 #include <linux/nodemask.h> 19 #include <linux/memblock.h> 20 #include <linux/memremap.h> 21 #include <linux/memory.h> 22 #include <linux/fs.h> 23 #include <linux/io.h> 24 #include <linux/mm.h> 25 #include <linux/vmalloc.h> 26 #include <linux/set_memory.h> 27 #include <linux/kfence.h> 28 #include <linux/pkeys.h> 29 #include <linux/mm_inline.h> 30 #include <linux/pagewalk.h> 31 #include <linux/stop_machine.h> 32 33 #include <asm/barrier.h> 34 #include <asm/cputype.h> 35 #include <asm/fixmap.h> 36 #include <asm/kasan.h> 37 #include <asm/kernel-pgtable.h> 38 #include <asm/sections.h> 39 #include <asm/setup.h> 40 #include <linux/sizes.h> 41 #include <asm/tlb.h> 42 #include <asm/mmu_context.h> 43 #include <asm/ptdump.h> 44 #include <asm/tlbflush.h> 45 #include <asm/pgalloc.h> 46 #include <asm/kfence.h> 47 48 #define NO_BLOCK_MAPPINGS BIT(0) 49 #define NO_CONT_MAPPINGS BIT(1) 50 #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ 51 52 #define INVALID_PHYS_ADDR (-1ULL) 53 54 DEFINE_STATIC_KEY_FALSE(arm64_ptdump_lock_key); 55 56 u64 kimage_voffset __ro_after_init; 57 EXPORT_SYMBOL(kimage_voffset); 58 59 u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 }; 60 61 static bool rodata_is_rw __ro_after_init = true; 62 63 /* 64 * The booting CPU updates the failed status @__early_cpu_boot_status, 65 * with MMU turned off. 66 */ 67 long __section(".mmuoff.data.write") __early_cpu_boot_status; 68 69 /* 70 * Empty_zero_page is a special page that is used for zero-initialized data 71 * and COW. 72 */ 73 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 74 EXPORT_SYMBOL(empty_zero_page); 75 76 static DEFINE_SPINLOCK(swapper_pgdir_lock); 77 static DEFINE_MUTEX(fixmap_lock); 78 79 void noinstr set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 80 { 81 pgd_t *fixmap_pgdp; 82 83 /* 84 * Don't bother with the fixmap if swapper_pg_dir is still mapped 85 * writable in the kernel mapping. 86 */ 87 if (rodata_is_rw) { 88 WRITE_ONCE(*pgdp, pgd); 89 dsb(ishst); 90 isb(); 91 return; 92 } 93 94 spin_lock(&swapper_pgdir_lock); 95 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 96 WRITE_ONCE(*fixmap_pgdp, pgd); 97 /* 98 * We need dsb(ishst) here to ensure the page-table-walker sees 99 * our new entry before set_p?d() returns. The fixmap's 100 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 101 */ 102 pgd_clear_fixmap(); 103 spin_unlock(&swapper_pgdir_lock); 104 } 105 106 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 107 unsigned long size, pgprot_t vma_prot) 108 { 109 if (!pfn_is_map_memory(pfn)) 110 return pgprot_noncached(vma_prot); 111 else if (file->f_flags & O_SYNC) 112 return pgprot_writecombine(vma_prot); 113 return vma_prot; 114 } 115 EXPORT_SYMBOL(phys_mem_access_prot); 116 117 static phys_addr_t __init early_pgtable_alloc(enum pgtable_type pgtable_type) 118 { 119 phys_addr_t phys; 120 121 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 122 MEMBLOCK_ALLOC_NOLEAKTRACE); 123 if (!phys) 124 panic("Failed to allocate page table page\n"); 125 126 return phys; 127 } 128 129 bool pgattr_change_is_safe(pteval_t old, pteval_t new) 130 { 131 /* 132 * The following mapping attributes may be updated in live 133 * kernel mappings without the need for break-before-make. 134 */ 135 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG | 136 PTE_SWBITS_MASK; 137 138 /* creating or taking down mappings is always safe */ 139 if (!pte_valid(__pte(old)) || !pte_valid(__pte(new))) 140 return true; 141 142 /* A live entry's pfn should not change */ 143 if (pte_pfn(__pte(old)) != pte_pfn(__pte(new))) 144 return false; 145 146 /* live contiguous mappings may not be manipulated at all */ 147 if ((old | new) & PTE_CONT) 148 return false; 149 150 /* Transitioning from Non-Global to Global is unsafe */ 151 if (old & ~new & PTE_NG) 152 return false; 153 154 /* 155 * Changing the memory type between Normal and Normal-Tagged is safe 156 * since Tagged is considered a permission attribute from the 157 * mismatched attribute aliases perspective. 158 */ 159 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 160 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 161 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 162 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 163 mask |= PTE_ATTRINDX_MASK; 164 165 return ((old ^ new) & ~mask) == 0; 166 } 167 168 static void init_clear_pgtable(void *table) 169 { 170 clear_page(table); 171 172 /* Ensure the zeroing is observed by page table walks. */ 173 dsb(ishst); 174 } 175 176 static void init_pte(pte_t *ptep, unsigned long addr, unsigned long end, 177 phys_addr_t phys, pgprot_t prot) 178 { 179 do { 180 pte_t old_pte = __ptep_get(ptep); 181 182 /* 183 * Required barriers to make this visible to the table walker 184 * are deferred to the end of alloc_init_cont_pte(). 185 */ 186 __set_pte_nosync(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 187 188 /* 189 * After the PTE entry has been populated once, we 190 * only allow updates to the permission attributes. 191 */ 192 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 193 pte_val(__ptep_get(ptep)))); 194 195 phys += PAGE_SIZE; 196 } while (ptep++, addr += PAGE_SIZE, addr != end); 197 } 198 199 static int alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 200 unsigned long end, phys_addr_t phys, 201 pgprot_t prot, 202 phys_addr_t (*pgtable_alloc)(enum pgtable_type), 203 int flags) 204 { 205 unsigned long next; 206 pmd_t pmd = READ_ONCE(*pmdp); 207 pte_t *ptep; 208 209 BUG_ON(pmd_sect(pmd)); 210 if (pmd_none(pmd)) { 211 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN | PMD_TABLE_AF; 212 phys_addr_t pte_phys; 213 214 if (flags & NO_EXEC_MAPPINGS) 215 pmdval |= PMD_TABLE_PXN; 216 BUG_ON(!pgtable_alloc); 217 pte_phys = pgtable_alloc(TABLE_PTE); 218 if (pte_phys == INVALID_PHYS_ADDR) 219 return -ENOMEM; 220 ptep = pte_set_fixmap(pte_phys); 221 init_clear_pgtable(ptep); 222 ptep += pte_index(addr); 223 __pmd_populate(pmdp, pte_phys, pmdval); 224 } else { 225 BUG_ON(pmd_bad(pmd)); 226 ptep = pte_set_fixmap_offset(pmdp, addr); 227 } 228 229 do { 230 pgprot_t __prot = prot; 231 232 next = pte_cont_addr_end(addr, end); 233 234 /* use a contiguous mapping if the range is suitably aligned */ 235 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 236 (flags & NO_CONT_MAPPINGS) == 0) 237 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 238 239 init_pte(ptep, addr, next, phys, __prot); 240 241 ptep += pte_index(next) - pte_index(addr); 242 phys += next - addr; 243 } while (addr = next, addr != end); 244 245 /* 246 * Note: barriers and maintenance necessary to clear the fixmap slot 247 * ensure that all previous pgtable writes are visible to the table 248 * walker. 249 */ 250 pte_clear_fixmap(); 251 252 return 0; 253 } 254 255 static int init_pmd(pmd_t *pmdp, unsigned long addr, unsigned long end, 256 phys_addr_t phys, pgprot_t prot, 257 phys_addr_t (*pgtable_alloc)(enum pgtable_type), int flags) 258 { 259 unsigned long next; 260 261 do { 262 pmd_t old_pmd = READ_ONCE(*pmdp); 263 264 next = pmd_addr_end(addr, end); 265 266 /* try section mapping first */ 267 if (((addr | next | phys) & ~PMD_MASK) == 0 && 268 (flags & NO_BLOCK_MAPPINGS) == 0) { 269 pmd_set_huge(pmdp, phys, prot); 270 271 /* 272 * After the PMD entry has been populated once, we 273 * only allow updates to the permission attributes. 274 */ 275 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 276 READ_ONCE(pmd_val(*pmdp)))); 277 } else { 278 int ret; 279 280 ret = alloc_init_cont_pte(pmdp, addr, next, phys, prot, 281 pgtable_alloc, flags); 282 if (ret) 283 return ret; 284 285 BUG_ON(pmd_val(old_pmd) != 0 && 286 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 287 } 288 phys += next - addr; 289 } while (pmdp++, addr = next, addr != end); 290 291 return 0; 292 } 293 294 static int alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 295 unsigned long end, phys_addr_t phys, 296 pgprot_t prot, 297 phys_addr_t (*pgtable_alloc)(enum pgtable_type), 298 int flags) 299 { 300 int ret; 301 unsigned long next; 302 pud_t pud = READ_ONCE(*pudp); 303 pmd_t *pmdp; 304 305 /* 306 * Check for initial section mappings in the pgd/pud. 307 */ 308 BUG_ON(pud_sect(pud)); 309 if (pud_none(pud)) { 310 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN | PUD_TABLE_AF; 311 phys_addr_t pmd_phys; 312 313 if (flags & NO_EXEC_MAPPINGS) 314 pudval |= PUD_TABLE_PXN; 315 BUG_ON(!pgtable_alloc); 316 pmd_phys = pgtable_alloc(TABLE_PMD); 317 if (pmd_phys == INVALID_PHYS_ADDR) 318 return -ENOMEM; 319 pmdp = pmd_set_fixmap(pmd_phys); 320 init_clear_pgtable(pmdp); 321 pmdp += pmd_index(addr); 322 __pud_populate(pudp, pmd_phys, pudval); 323 } else { 324 BUG_ON(pud_bad(pud)); 325 pmdp = pmd_set_fixmap_offset(pudp, addr); 326 } 327 328 do { 329 pgprot_t __prot = prot; 330 331 next = pmd_cont_addr_end(addr, end); 332 333 /* use a contiguous mapping if the range is suitably aligned */ 334 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 335 (flags & NO_CONT_MAPPINGS) == 0) 336 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 337 338 ret = init_pmd(pmdp, addr, next, phys, __prot, pgtable_alloc, flags); 339 if (ret) 340 goto out; 341 342 pmdp += pmd_index(next) - pmd_index(addr); 343 phys += next - addr; 344 } while (addr = next, addr != end); 345 346 out: 347 pmd_clear_fixmap(); 348 349 return ret; 350 } 351 352 static int alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, 353 phys_addr_t phys, pgprot_t prot, 354 phys_addr_t (*pgtable_alloc)(enum pgtable_type), 355 int flags) 356 { 357 int ret = 0; 358 unsigned long next; 359 p4d_t p4d = READ_ONCE(*p4dp); 360 pud_t *pudp; 361 362 if (p4d_none(p4d)) { 363 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN | P4D_TABLE_AF; 364 phys_addr_t pud_phys; 365 366 if (flags & NO_EXEC_MAPPINGS) 367 p4dval |= P4D_TABLE_PXN; 368 BUG_ON(!pgtable_alloc); 369 pud_phys = pgtable_alloc(TABLE_PUD); 370 if (pud_phys == INVALID_PHYS_ADDR) 371 return -ENOMEM; 372 pudp = pud_set_fixmap(pud_phys); 373 init_clear_pgtable(pudp); 374 pudp += pud_index(addr); 375 __p4d_populate(p4dp, pud_phys, p4dval); 376 } else { 377 BUG_ON(p4d_bad(p4d)); 378 pudp = pud_set_fixmap_offset(p4dp, addr); 379 } 380 381 do { 382 pud_t old_pud = READ_ONCE(*pudp); 383 384 next = pud_addr_end(addr, end); 385 386 /* 387 * For 4K granule only, attempt to put down a 1GB block 388 */ 389 if (pud_sect_supported() && 390 ((addr | next | phys) & ~PUD_MASK) == 0 && 391 (flags & NO_BLOCK_MAPPINGS) == 0) { 392 pud_set_huge(pudp, phys, prot); 393 394 /* 395 * After the PUD entry has been populated once, we 396 * only allow updates to the permission attributes. 397 */ 398 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 399 READ_ONCE(pud_val(*pudp)))); 400 } else { 401 ret = alloc_init_cont_pmd(pudp, addr, next, phys, prot, 402 pgtable_alloc, flags); 403 if (ret) 404 goto out; 405 406 BUG_ON(pud_val(old_pud) != 0 && 407 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 408 } 409 phys += next - addr; 410 } while (pudp++, addr = next, addr != end); 411 412 out: 413 pud_clear_fixmap(); 414 415 return ret; 416 } 417 418 static int alloc_init_p4d(pgd_t *pgdp, unsigned long addr, unsigned long end, 419 phys_addr_t phys, pgprot_t prot, 420 phys_addr_t (*pgtable_alloc)(enum pgtable_type), 421 int flags) 422 { 423 int ret; 424 unsigned long next; 425 pgd_t pgd = READ_ONCE(*pgdp); 426 p4d_t *p4dp; 427 428 if (pgd_none(pgd)) { 429 pgdval_t pgdval = PGD_TYPE_TABLE | PGD_TABLE_UXN | PGD_TABLE_AF; 430 phys_addr_t p4d_phys; 431 432 if (flags & NO_EXEC_MAPPINGS) 433 pgdval |= PGD_TABLE_PXN; 434 BUG_ON(!pgtable_alloc); 435 p4d_phys = pgtable_alloc(TABLE_P4D); 436 if (p4d_phys == INVALID_PHYS_ADDR) 437 return -ENOMEM; 438 p4dp = p4d_set_fixmap(p4d_phys); 439 init_clear_pgtable(p4dp); 440 p4dp += p4d_index(addr); 441 __pgd_populate(pgdp, p4d_phys, pgdval); 442 } else { 443 BUG_ON(pgd_bad(pgd)); 444 p4dp = p4d_set_fixmap_offset(pgdp, addr); 445 } 446 447 do { 448 p4d_t old_p4d = READ_ONCE(*p4dp); 449 450 next = p4d_addr_end(addr, end); 451 452 ret = alloc_init_pud(p4dp, addr, next, phys, prot, 453 pgtable_alloc, flags); 454 if (ret) 455 goto out; 456 457 BUG_ON(p4d_val(old_p4d) != 0 && 458 p4d_val(old_p4d) != READ_ONCE(p4d_val(*p4dp))); 459 460 phys += next - addr; 461 } while (p4dp++, addr = next, addr != end); 462 463 out: 464 p4d_clear_fixmap(); 465 466 return ret; 467 } 468 469 static int __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, 470 unsigned long virt, phys_addr_t size, 471 pgprot_t prot, 472 phys_addr_t (*pgtable_alloc)(enum pgtable_type), 473 int flags) 474 { 475 int ret; 476 unsigned long addr, end, next; 477 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 478 479 /* 480 * If the virtual and physical address don't have the same offset 481 * within a page, we cannot map the region as the caller expects. 482 */ 483 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 484 return -EINVAL; 485 486 phys &= PAGE_MASK; 487 addr = virt & PAGE_MASK; 488 end = PAGE_ALIGN(virt + size); 489 490 do { 491 next = pgd_addr_end(addr, end); 492 ret = alloc_init_p4d(pgdp, addr, next, phys, prot, pgtable_alloc, 493 flags); 494 if (ret) 495 return ret; 496 phys += next - addr; 497 } while (pgdp++, addr = next, addr != end); 498 499 return 0; 500 } 501 502 static int __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 503 unsigned long virt, phys_addr_t size, 504 pgprot_t prot, 505 phys_addr_t (*pgtable_alloc)(enum pgtable_type), 506 int flags) 507 { 508 int ret; 509 510 mutex_lock(&fixmap_lock); 511 ret = __create_pgd_mapping_locked(pgdir, phys, virt, size, prot, 512 pgtable_alloc, flags); 513 mutex_unlock(&fixmap_lock); 514 515 return ret; 516 } 517 518 static void early_create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 519 unsigned long virt, phys_addr_t size, 520 pgprot_t prot, 521 phys_addr_t (*pgtable_alloc)(enum pgtable_type), 522 int flags) 523 { 524 int ret; 525 526 ret = __create_pgd_mapping(pgdir, phys, virt, size, prot, pgtable_alloc, 527 flags); 528 if (ret) 529 panic("Failed to create page tables\n"); 530 } 531 532 static phys_addr_t __pgd_pgtable_alloc(struct mm_struct *mm, gfp_t gfp, 533 enum pgtable_type pgtable_type) 534 { 535 /* Page is zeroed by init_clear_pgtable() so don't duplicate effort. */ 536 struct ptdesc *ptdesc = pagetable_alloc(gfp & ~__GFP_ZERO, 0); 537 phys_addr_t pa; 538 539 if (!ptdesc) 540 return INVALID_PHYS_ADDR; 541 542 pa = page_to_phys(ptdesc_page(ptdesc)); 543 544 switch (pgtable_type) { 545 case TABLE_PTE: 546 BUG_ON(!pagetable_pte_ctor(mm, ptdesc)); 547 break; 548 case TABLE_PMD: 549 BUG_ON(!pagetable_pmd_ctor(mm, ptdesc)); 550 break; 551 case TABLE_PUD: 552 pagetable_pud_ctor(ptdesc); 553 break; 554 case TABLE_P4D: 555 pagetable_p4d_ctor(ptdesc); 556 break; 557 } 558 559 return pa; 560 } 561 562 static phys_addr_t 563 try_pgd_pgtable_alloc_init_mm(enum pgtable_type pgtable_type, gfp_t gfp) 564 { 565 return __pgd_pgtable_alloc(&init_mm, gfp, pgtable_type); 566 } 567 568 static phys_addr_t __maybe_unused 569 pgd_pgtable_alloc_init_mm(enum pgtable_type pgtable_type) 570 { 571 return __pgd_pgtable_alloc(&init_mm, GFP_PGTABLE_KERNEL, pgtable_type); 572 } 573 574 static phys_addr_t 575 pgd_pgtable_alloc_special_mm(enum pgtable_type pgtable_type) 576 { 577 return __pgd_pgtable_alloc(NULL, GFP_PGTABLE_KERNEL, pgtable_type); 578 } 579 580 static void split_contpte(pte_t *ptep) 581 { 582 int i; 583 584 ptep = PTR_ALIGN_DOWN(ptep, sizeof(*ptep) * CONT_PTES); 585 for (i = 0; i < CONT_PTES; i++, ptep++) 586 __set_pte(ptep, pte_mknoncont(__ptep_get(ptep))); 587 } 588 589 static int split_pmd(pmd_t *pmdp, pmd_t pmd, gfp_t gfp, bool to_cont) 590 { 591 pmdval_t tableprot = PMD_TYPE_TABLE | PMD_TABLE_UXN | PMD_TABLE_AF; 592 unsigned long pfn = pmd_pfn(pmd); 593 pgprot_t prot = pmd_pgprot(pmd); 594 phys_addr_t pte_phys; 595 pte_t *ptep; 596 int i; 597 598 pte_phys = try_pgd_pgtable_alloc_init_mm(TABLE_PTE, gfp); 599 if (pte_phys == INVALID_PHYS_ADDR) 600 return -ENOMEM; 601 ptep = (pte_t *)phys_to_virt(pte_phys); 602 603 if (pgprot_val(prot) & PMD_SECT_PXN) 604 tableprot |= PMD_TABLE_PXN; 605 606 prot = __pgprot((pgprot_val(prot) & ~PTE_TYPE_MASK) | PTE_TYPE_PAGE); 607 if (!pmd_valid(pmd)) 608 prot = pte_pgprot(pte_mkinvalid(pfn_pte(0, prot))); 609 prot = __pgprot(pgprot_val(prot) & ~PTE_CONT); 610 if (to_cont) 611 prot = __pgprot(pgprot_val(prot) | PTE_CONT); 612 613 for (i = 0; i < PTRS_PER_PTE; i++, ptep++, pfn++) 614 __set_pte(ptep, pfn_pte(pfn, prot)); 615 616 /* 617 * Ensure the pte entries are visible to the table walker by the time 618 * the pmd entry that points to the ptes is visible. 619 */ 620 dsb(ishst); 621 __pmd_populate(pmdp, pte_phys, tableprot); 622 623 return 0; 624 } 625 626 static void split_contpmd(pmd_t *pmdp) 627 { 628 int i; 629 630 pmdp = PTR_ALIGN_DOWN(pmdp, sizeof(*pmdp) * CONT_PMDS); 631 for (i = 0; i < CONT_PMDS; i++, pmdp++) 632 set_pmd(pmdp, pmd_mknoncont(pmdp_get(pmdp))); 633 } 634 635 static int split_pud(pud_t *pudp, pud_t pud, gfp_t gfp, bool to_cont) 636 { 637 pudval_t tableprot = PUD_TYPE_TABLE | PUD_TABLE_UXN | PUD_TABLE_AF; 638 unsigned int step = PMD_SIZE >> PAGE_SHIFT; 639 unsigned long pfn = pud_pfn(pud); 640 pgprot_t prot = pud_pgprot(pud); 641 phys_addr_t pmd_phys; 642 pmd_t *pmdp; 643 int i; 644 645 pmd_phys = try_pgd_pgtable_alloc_init_mm(TABLE_PMD, gfp); 646 if (pmd_phys == INVALID_PHYS_ADDR) 647 return -ENOMEM; 648 pmdp = (pmd_t *)phys_to_virt(pmd_phys); 649 650 if (pgprot_val(prot) & PMD_SECT_PXN) 651 tableprot |= PUD_TABLE_PXN; 652 653 prot = __pgprot((pgprot_val(prot) & ~PMD_TYPE_MASK) | PMD_TYPE_SECT); 654 if (!pud_valid(pud)) 655 prot = pmd_pgprot(pmd_mkinvalid(pfn_pmd(0, prot))); 656 prot = __pgprot(pgprot_val(prot) & ~PTE_CONT); 657 if (to_cont) 658 prot = __pgprot(pgprot_val(prot) | PTE_CONT); 659 660 for (i = 0; i < PTRS_PER_PMD; i++, pmdp++, pfn += step) 661 set_pmd(pmdp, pfn_pmd(pfn, prot)); 662 663 /* 664 * Ensure the pmd entries are visible to the table walker by the time 665 * the pud entry that points to the pmds is visible. 666 */ 667 dsb(ishst); 668 __pud_populate(pudp, pmd_phys, tableprot); 669 670 return 0; 671 } 672 673 static int split_kernel_leaf_mapping_locked(unsigned long addr) 674 { 675 pgd_t *pgdp, pgd; 676 p4d_t *p4dp, p4d; 677 pud_t *pudp, pud; 678 pmd_t *pmdp, pmd; 679 pte_t *ptep, pte; 680 int ret = 0; 681 682 /* 683 * PGD: If addr is PGD aligned then addr already describes a leaf 684 * boundary. If not present then there is nothing to split. 685 */ 686 if (ALIGN_DOWN(addr, PGDIR_SIZE) == addr) 687 goto out; 688 pgdp = pgd_offset_k(addr); 689 pgd = pgdp_get(pgdp); 690 if (!pgd_present(pgd)) 691 goto out; 692 693 /* 694 * P4D: If addr is P4D aligned then addr already describes a leaf 695 * boundary. If not present then there is nothing to split. 696 */ 697 if (ALIGN_DOWN(addr, P4D_SIZE) == addr) 698 goto out; 699 p4dp = p4d_offset(pgdp, addr); 700 p4d = p4dp_get(p4dp); 701 if (!p4d_present(p4d)) 702 goto out; 703 704 /* 705 * PUD: If addr is PUD aligned then addr already describes a leaf 706 * boundary. If not present then there is nothing to split. Otherwise, 707 * if we have a pud leaf, split to contpmd. 708 */ 709 if (ALIGN_DOWN(addr, PUD_SIZE) == addr) 710 goto out; 711 pudp = pud_offset(p4dp, addr); 712 pud = pudp_get(pudp); 713 if (!pud_present(pud)) 714 goto out; 715 if (pud_leaf(pud)) { 716 ret = split_pud(pudp, pud, GFP_PGTABLE_KERNEL, true); 717 if (ret) 718 goto out; 719 } 720 721 /* 722 * CONTPMD: If addr is CONTPMD aligned then addr already describes a 723 * leaf boundary. If not present then there is nothing to split. 724 * Otherwise, if we have a contpmd leaf, split to pmd. 725 */ 726 if (ALIGN_DOWN(addr, CONT_PMD_SIZE) == addr) 727 goto out; 728 pmdp = pmd_offset(pudp, addr); 729 pmd = pmdp_get(pmdp); 730 if (!pmd_present(pmd)) 731 goto out; 732 if (pmd_leaf(pmd)) { 733 if (pmd_cont(pmd)) 734 split_contpmd(pmdp); 735 /* 736 * PMD: If addr is PMD aligned then addr already describes a 737 * leaf boundary. Otherwise, split to contpte. 738 */ 739 if (ALIGN_DOWN(addr, PMD_SIZE) == addr) 740 goto out; 741 ret = split_pmd(pmdp, pmd, GFP_PGTABLE_KERNEL, true); 742 if (ret) 743 goto out; 744 } 745 746 /* 747 * CONTPTE: If addr is CONTPTE aligned then addr already describes a 748 * leaf boundary. If not present then there is nothing to split. 749 * Otherwise, if we have a contpte leaf, split to pte. 750 */ 751 if (ALIGN_DOWN(addr, CONT_PTE_SIZE) == addr) 752 goto out; 753 ptep = pte_offset_kernel(pmdp, addr); 754 pte = __ptep_get(ptep); 755 if (!pte_present(pte)) 756 goto out; 757 if (pte_cont(pte)) 758 split_contpte(ptep); 759 760 out: 761 return ret; 762 } 763 764 static inline bool force_pte_mapping(void) 765 { 766 const bool bbml2 = system_capabilities_finalized() ? 767 system_supports_bbml2_noabort() : cpu_supports_bbml2_noabort(); 768 769 if (debug_pagealloc_enabled()) 770 return true; 771 if (bbml2) 772 return false; 773 return rodata_full || arm64_kfence_can_set_direct_map() || is_realm_world(); 774 } 775 776 static DEFINE_MUTEX(pgtable_split_lock); 777 static bool linear_map_requires_bbml2; 778 779 int split_kernel_leaf_mapping(unsigned long start, unsigned long end) 780 { 781 int ret; 782 783 /* 784 * If the region is within a pte-mapped area, there is no need to try to 785 * split. Additionally, CONFIG_DEBUG_PAGEALLOC and CONFIG_KFENCE may 786 * change permissions from atomic context so for those cases (which are 787 * always pte-mapped), we must not go any further because taking the 788 * mutex below may sleep. Do not call force_pte_mapping() here because 789 * it could return a confusing result if called from a secondary cpu 790 * prior to finalizing caps. Instead, linear_map_requires_bbml2 gives us 791 * what we need. 792 */ 793 if (!linear_map_requires_bbml2 || is_kfence_address((void *)start)) 794 return 0; 795 796 if (!system_supports_bbml2_noabort()) { 797 /* 798 * !BBML2_NOABORT systems should not be trying to change 799 * permissions on anything that is not pte-mapped in the first 800 * place. Just return early and let the permission change code 801 * raise a warning if not already pte-mapped. 802 */ 803 if (system_capabilities_finalized()) 804 return 0; 805 806 /* 807 * Boot-time: split_kernel_leaf_mapping_locked() allocates from 808 * page allocator. Can't split until it's available. 809 */ 810 if (WARN_ON(!page_alloc_available)) 811 return -EBUSY; 812 813 /* 814 * Boot-time: Started secondary cpus but don't know if they 815 * support BBML2_NOABORT yet. Can't allow splitting in this 816 * window in case they don't. 817 */ 818 if (WARN_ON(num_online_cpus() > 1)) 819 return -EBUSY; 820 } 821 822 /* 823 * Ensure start and end are at least page-aligned since this is the 824 * finest granularity we can split to. 825 */ 826 if (start != PAGE_ALIGN(start) || end != PAGE_ALIGN(end)) 827 return -EINVAL; 828 829 mutex_lock(&pgtable_split_lock); 830 arch_enter_lazy_mmu_mode(); 831 832 /* 833 * The split_kernel_leaf_mapping_locked() may sleep, it is not a 834 * problem for ARM64 since ARM64's lazy MMU implementation allows 835 * sleeping. 836 * 837 * Optimize for the common case of splitting out a single page from a 838 * larger mapping. Here we can just split on the "least aligned" of 839 * start and end and this will guarantee that there must also be a split 840 * on the more aligned address since the both addresses must be in the 841 * same contpte block and it must have been split to ptes. 842 */ 843 if (end - start == PAGE_SIZE) { 844 start = __ffs(start) < __ffs(end) ? start : end; 845 ret = split_kernel_leaf_mapping_locked(start); 846 } else { 847 ret = split_kernel_leaf_mapping_locked(start); 848 if (!ret) 849 ret = split_kernel_leaf_mapping_locked(end); 850 } 851 852 arch_leave_lazy_mmu_mode(); 853 mutex_unlock(&pgtable_split_lock); 854 return ret; 855 } 856 857 static int split_to_ptes_pud_entry(pud_t *pudp, unsigned long addr, 858 unsigned long next, struct mm_walk *walk) 859 { 860 gfp_t gfp = *(gfp_t *)walk->private; 861 pud_t pud = pudp_get(pudp); 862 int ret = 0; 863 864 if (pud_leaf(pud)) 865 ret = split_pud(pudp, pud, gfp, false); 866 867 return ret; 868 } 869 870 static int split_to_ptes_pmd_entry(pmd_t *pmdp, unsigned long addr, 871 unsigned long next, struct mm_walk *walk) 872 { 873 gfp_t gfp = *(gfp_t *)walk->private; 874 pmd_t pmd = pmdp_get(pmdp); 875 int ret = 0; 876 877 if (pmd_leaf(pmd)) { 878 if (pmd_cont(pmd)) 879 split_contpmd(pmdp); 880 ret = split_pmd(pmdp, pmd, gfp, false); 881 882 /* 883 * We have split the pmd directly to ptes so there is no need to 884 * visit each pte to check if they are contpte. 885 */ 886 walk->action = ACTION_CONTINUE; 887 } 888 889 return ret; 890 } 891 892 static int split_to_ptes_pte_entry(pte_t *ptep, unsigned long addr, 893 unsigned long next, struct mm_walk *walk) 894 { 895 pte_t pte = __ptep_get(ptep); 896 897 if (pte_cont(pte)) 898 split_contpte(ptep); 899 900 return 0; 901 } 902 903 static const struct mm_walk_ops split_to_ptes_ops = { 904 .pud_entry = split_to_ptes_pud_entry, 905 .pmd_entry = split_to_ptes_pmd_entry, 906 .pte_entry = split_to_ptes_pte_entry, 907 }; 908 909 static int range_split_to_ptes(unsigned long start, unsigned long end, gfp_t gfp) 910 { 911 int ret; 912 913 arch_enter_lazy_mmu_mode(); 914 ret = walk_kernel_page_table_range_lockless(start, end, 915 &split_to_ptes_ops, NULL, &gfp); 916 arch_leave_lazy_mmu_mode(); 917 918 return ret; 919 } 920 921 u32 idmap_kpti_bbml2_flag; 922 923 static void __init init_idmap_kpti_bbml2_flag(void) 924 { 925 WRITE_ONCE(idmap_kpti_bbml2_flag, 1); 926 /* Must be visible to other CPUs before stop_machine() is called. */ 927 smp_mb(); 928 } 929 930 static int __init linear_map_split_to_ptes(void *__unused) 931 { 932 /* 933 * Repainting the linear map must be done by CPU0 (the boot CPU) because 934 * that's the only CPU that we know supports BBML2. The other CPUs will 935 * be held in a waiting area with the idmap active. 936 */ 937 if (!smp_processor_id()) { 938 unsigned long lstart = _PAGE_OFFSET(vabits_actual); 939 unsigned long lend = PAGE_END; 940 unsigned long kstart = (unsigned long)lm_alias(_stext); 941 unsigned long kend = (unsigned long)lm_alias(__init_begin); 942 int ret; 943 944 /* 945 * Wait for all secondary CPUs to be put into the waiting area. 946 */ 947 smp_cond_load_acquire(&idmap_kpti_bbml2_flag, VAL == num_online_cpus()); 948 949 /* 950 * Walk all of the linear map [lstart, lend), except the kernel 951 * linear map alias [kstart, kend), and split all mappings to 952 * PTE. The kernel alias remains static throughout runtime so 953 * can continue to be safely mapped with large mappings. 954 */ 955 ret = range_split_to_ptes(lstart, kstart, GFP_ATOMIC); 956 if (!ret) 957 ret = range_split_to_ptes(kend, lend, GFP_ATOMIC); 958 if (ret) 959 panic("Failed to split linear map\n"); 960 flush_tlb_kernel_range(lstart, lend); 961 962 /* 963 * Relies on dsb in flush_tlb_kernel_range() to avoid reordering 964 * before any page table split operations. 965 */ 966 WRITE_ONCE(idmap_kpti_bbml2_flag, 0); 967 } else { 968 typedef void (wait_split_fn)(void); 969 extern wait_split_fn wait_linear_map_split_to_ptes; 970 wait_split_fn *wait_fn; 971 972 wait_fn = (void *)__pa_symbol(wait_linear_map_split_to_ptes); 973 974 /* 975 * At least one secondary CPU doesn't support BBML2 so cannot 976 * tolerate the size of the live mappings changing. So have the 977 * secondary CPUs wait for the boot CPU to make the changes 978 * with the idmap active and init_mm inactive. 979 */ 980 cpu_install_idmap(); 981 wait_fn(); 982 cpu_uninstall_idmap(); 983 } 984 985 return 0; 986 } 987 988 void __init linear_map_maybe_split_to_ptes(void) 989 { 990 if (linear_map_requires_bbml2 && !system_supports_bbml2_noabort()) { 991 init_idmap_kpti_bbml2_flag(); 992 stop_machine(linear_map_split_to_ptes, NULL, cpu_online_mask); 993 } 994 } 995 996 /* 997 * This function can only be used to modify existing table entries, 998 * without allocating new levels of table. Note that this permits the 999 * creation of new section or page entries. 1000 */ 1001 void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 1002 phys_addr_t size, pgprot_t prot) 1003 { 1004 if (virt < PAGE_OFFSET) { 1005 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 1006 &phys, virt); 1007 return; 1008 } 1009 early_create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 1010 NO_CONT_MAPPINGS); 1011 } 1012 1013 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 1014 unsigned long virt, phys_addr_t size, 1015 pgprot_t prot, bool page_mappings_only) 1016 { 1017 int flags = 0; 1018 1019 BUG_ON(mm == &init_mm); 1020 1021 if (page_mappings_only) 1022 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1023 1024 early_create_pgd_mapping(mm->pgd, phys, virt, size, prot, 1025 pgd_pgtable_alloc_special_mm, flags); 1026 } 1027 1028 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 1029 phys_addr_t size, pgprot_t prot) 1030 { 1031 if (virt < PAGE_OFFSET) { 1032 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 1033 &phys, virt); 1034 return; 1035 } 1036 1037 early_create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 1038 NO_CONT_MAPPINGS); 1039 1040 /* flush the TLBs after updating live kernel mappings */ 1041 flush_tlb_kernel_range(virt, virt + size); 1042 } 1043 1044 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 1045 phys_addr_t end, pgprot_t prot, int flags) 1046 { 1047 early_create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 1048 prot, early_pgtable_alloc, flags); 1049 } 1050 1051 void __init mark_linear_text_alias_ro(void) 1052 { 1053 /* 1054 * Remove the write permissions from the linear alias of .text/.rodata 1055 */ 1056 update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text), 1057 (unsigned long)__init_begin - (unsigned long)_text, 1058 PAGE_KERNEL_RO); 1059 } 1060 1061 #ifdef CONFIG_KFENCE 1062 1063 bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL; 1064 1065 /* early_param() will be parsed before map_mem() below. */ 1066 static int __init parse_kfence_early_init(char *arg) 1067 { 1068 int val; 1069 1070 if (get_option(&arg, &val)) 1071 kfence_early_init = !!val; 1072 return 0; 1073 } 1074 early_param("kfence.sample_interval", parse_kfence_early_init); 1075 1076 static phys_addr_t __init arm64_kfence_alloc_pool(void) 1077 { 1078 phys_addr_t kfence_pool; 1079 1080 if (!kfence_early_init) 1081 return 0; 1082 1083 kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); 1084 if (!kfence_pool) { 1085 pr_err("failed to allocate kfence pool\n"); 1086 kfence_early_init = false; 1087 return 0; 1088 } 1089 1090 /* Temporarily mark as NOMAP. */ 1091 memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); 1092 1093 return kfence_pool; 1094 } 1095 1096 static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) 1097 { 1098 if (!kfence_pool) 1099 return; 1100 1101 /* KFENCE pool needs page-level mapping. */ 1102 __map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE, 1103 pgprot_tagged(PAGE_KERNEL), 1104 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 1105 memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); 1106 __kfence_pool = phys_to_virt(kfence_pool); 1107 } 1108 1109 bool arch_kfence_init_pool(void) 1110 { 1111 unsigned long start = (unsigned long)__kfence_pool; 1112 unsigned long end = start + KFENCE_POOL_SIZE; 1113 int ret; 1114 1115 /* Exit early if we know the linear map is already pte-mapped. */ 1116 if (force_pte_mapping()) 1117 return true; 1118 1119 /* Kfence pool is already pte-mapped for the early init case. */ 1120 if (kfence_early_init) 1121 return true; 1122 1123 mutex_lock(&pgtable_split_lock); 1124 ret = range_split_to_ptes(start, end, GFP_PGTABLE_KERNEL); 1125 mutex_unlock(&pgtable_split_lock); 1126 1127 /* 1128 * Since the system supports bbml2_noabort, tlb invalidation is not 1129 * required here; the pgtable mappings have been split to pte but larger 1130 * entries may safely linger in the TLB. 1131 */ 1132 1133 return !ret; 1134 } 1135 #else /* CONFIG_KFENCE */ 1136 1137 static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; } 1138 static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { } 1139 1140 #endif /* CONFIG_KFENCE */ 1141 1142 static void __init map_mem(pgd_t *pgdp) 1143 { 1144 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 1145 phys_addr_t kernel_start = __pa_symbol(_text); 1146 phys_addr_t kernel_end = __pa_symbol(__init_begin); 1147 phys_addr_t start, end; 1148 phys_addr_t early_kfence_pool; 1149 int flags = NO_EXEC_MAPPINGS; 1150 u64 i; 1151 1152 /* 1153 * Setting hierarchical PXNTable attributes on table entries covering 1154 * the linear region is only possible if it is guaranteed that no table 1155 * entries at any level are being shared between the linear region and 1156 * the vmalloc region. Check whether this is true for the PGD level, in 1157 * which case it is guaranteed to be true for all other levels as well. 1158 * (Unless we are running with support for LPA2, in which case the 1159 * entire reduced VA space is covered by a single pgd_t which will have 1160 * been populated without the PXNTable attribute by the time we get here.) 1161 */ 1162 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end) && 1163 pgd_index(_PAGE_OFFSET(VA_BITS_MIN)) != PTRS_PER_PGD - 1); 1164 1165 early_kfence_pool = arm64_kfence_alloc_pool(); 1166 1167 linear_map_requires_bbml2 = !force_pte_mapping() && can_set_direct_map(); 1168 1169 if (force_pte_mapping()) 1170 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1171 1172 /* 1173 * Take care not to create a writable alias for the 1174 * read-only text and rodata sections of the kernel image. 1175 * So temporarily mark them as NOMAP to skip mappings in 1176 * the following for-loop 1177 */ 1178 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 1179 1180 /* map all the memory banks */ 1181 for_each_mem_range(i, &start, &end) { 1182 if (start >= end) 1183 break; 1184 /* 1185 * The linear map must allow allocation tags reading/writing 1186 * if MTE is present. Otherwise, it has the same attributes as 1187 * PAGE_KERNEL. 1188 */ 1189 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 1190 flags); 1191 } 1192 1193 /* 1194 * Map the linear alias of the [_text, __init_begin) interval 1195 * as non-executable now, and remove the write permission in 1196 * mark_linear_text_alias_ro() below (which will be called after 1197 * alternative patching has completed). This makes the contents 1198 * of the region accessible to subsystems such as hibernate, 1199 * but protects it from inadvertent modification or execution. 1200 * Note that contiguous mappings cannot be remapped in this way, 1201 * so we should avoid them here. 1202 */ 1203 __map_memblock(pgdp, kernel_start, kernel_end, 1204 PAGE_KERNEL, NO_CONT_MAPPINGS); 1205 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 1206 arm64_kfence_map_pool(early_kfence_pool, pgdp); 1207 } 1208 1209 void mark_rodata_ro(void) 1210 { 1211 unsigned long section_size; 1212 1213 /* 1214 * mark .rodata as read only. Use __init_begin rather than __end_rodata 1215 * to cover NOTES and EXCEPTION_TABLE. 1216 */ 1217 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 1218 WRITE_ONCE(rodata_is_rw, false); 1219 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 1220 section_size, PAGE_KERNEL_RO); 1221 /* mark the range between _text and _stext as read only. */ 1222 update_mapping_prot(__pa_symbol(_text), (unsigned long)_text, 1223 (unsigned long)_stext - (unsigned long)_text, 1224 PAGE_KERNEL_RO); 1225 } 1226 1227 static void __init declare_vma(struct vm_struct *vma, 1228 void *va_start, void *va_end, 1229 unsigned long vm_flags) 1230 { 1231 phys_addr_t pa_start = __pa_symbol(va_start); 1232 unsigned long size = va_end - va_start; 1233 1234 BUG_ON(!PAGE_ALIGNED(pa_start)); 1235 BUG_ON(!PAGE_ALIGNED(size)); 1236 1237 if (!(vm_flags & VM_NO_GUARD)) 1238 size += PAGE_SIZE; 1239 1240 vma->addr = va_start; 1241 vma->phys_addr = pa_start; 1242 vma->size = size; 1243 vma->flags = VM_MAP | vm_flags; 1244 vma->caller = __builtin_return_address(0); 1245 1246 vm_area_add_early(vma); 1247 } 1248 1249 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 1250 #define KPTI_NG_TEMP_VA (-(1UL << PMD_SHIFT)) 1251 1252 static phys_addr_t kpti_ng_temp_alloc __initdata; 1253 1254 static phys_addr_t __init kpti_ng_pgd_alloc(enum pgtable_type type) 1255 { 1256 kpti_ng_temp_alloc -= PAGE_SIZE; 1257 return kpti_ng_temp_alloc; 1258 } 1259 1260 static int __init __kpti_install_ng_mappings(void *__unused) 1261 { 1262 typedef void (kpti_remap_fn)(int, int, phys_addr_t, unsigned long); 1263 extern kpti_remap_fn idmap_kpti_install_ng_mappings; 1264 kpti_remap_fn *remap_fn; 1265 1266 int cpu = smp_processor_id(); 1267 int levels = CONFIG_PGTABLE_LEVELS; 1268 int order = order_base_2(levels); 1269 u64 kpti_ng_temp_pgd_pa = 0; 1270 pgd_t *kpti_ng_temp_pgd; 1271 u64 alloc = 0; 1272 1273 if (levels == 5 && !pgtable_l5_enabled()) 1274 levels = 4; 1275 else if (levels == 4 && !pgtable_l4_enabled()) 1276 levels = 3; 1277 1278 remap_fn = (void *)__pa_symbol(idmap_kpti_install_ng_mappings); 1279 1280 if (!cpu) { 1281 int ret; 1282 1283 alloc = __get_free_pages(GFP_ATOMIC | __GFP_ZERO, order); 1284 kpti_ng_temp_pgd = (pgd_t *)(alloc + (levels - 1) * PAGE_SIZE); 1285 kpti_ng_temp_alloc = kpti_ng_temp_pgd_pa = __pa(kpti_ng_temp_pgd); 1286 1287 // 1288 // Create a minimal page table hierarchy that permits us to map 1289 // the swapper page tables temporarily as we traverse them. 1290 // 1291 // The physical pages are laid out as follows: 1292 // 1293 // +--------+-/-------+-/------ +-/------ +-\\\--------+ 1294 // : PTE[] : | PMD[] : | PUD[] : | P4D[] : ||| PGD[] : 1295 // +--------+-\-------+-\------ +-\------ +-///--------+ 1296 // ^ 1297 // The first page is mapped into this hierarchy at a PMD_SHIFT 1298 // aligned virtual address, so that we can manipulate the PTE 1299 // level entries while the mapping is active. The first entry 1300 // covers the PTE[] page itself, the remaining entries are free 1301 // to be used as a ad-hoc fixmap. 1302 // 1303 ret = __create_pgd_mapping_locked(kpti_ng_temp_pgd, __pa(alloc), 1304 KPTI_NG_TEMP_VA, PAGE_SIZE, PAGE_KERNEL, 1305 kpti_ng_pgd_alloc, 0); 1306 if (ret) 1307 panic("Failed to create page tables\n"); 1308 } 1309 1310 cpu_install_idmap(); 1311 remap_fn(cpu, num_online_cpus(), kpti_ng_temp_pgd_pa, KPTI_NG_TEMP_VA); 1312 cpu_uninstall_idmap(); 1313 1314 if (!cpu) { 1315 free_pages(alloc, order); 1316 arm64_use_ng_mappings = true; 1317 } 1318 1319 return 0; 1320 } 1321 1322 void __init kpti_install_ng_mappings(void) 1323 { 1324 /* Check whether KPTI is going to be used */ 1325 if (!arm64_kernel_unmapped_at_el0()) 1326 return; 1327 1328 /* 1329 * We don't need to rewrite the page-tables if either we've done 1330 * it already or we have KASLR enabled and therefore have not 1331 * created any global mappings at all. 1332 */ 1333 if (arm64_use_ng_mappings) 1334 return; 1335 1336 init_idmap_kpti_bbml2_flag(); 1337 stop_machine(__kpti_install_ng_mappings, NULL, cpu_online_mask); 1338 } 1339 1340 static pgprot_t __init kernel_exec_prot(void) 1341 { 1342 return rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 1343 } 1344 1345 static int __init map_entry_trampoline(void) 1346 { 1347 int i; 1348 1349 if (!arm64_kernel_unmapped_at_el0()) 1350 return 0; 1351 1352 pgprot_t prot = kernel_exec_prot(); 1353 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 1354 1355 /* The trampoline is always mapped and can therefore be global */ 1356 pgprot_val(prot) &= ~PTE_NG; 1357 1358 /* Map only the text into the trampoline page table */ 1359 memset(tramp_pg_dir, 0, PGD_SIZE); 1360 early_create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 1361 entry_tramp_text_size(), prot, 1362 pgd_pgtable_alloc_init_mm, NO_BLOCK_MAPPINGS); 1363 1364 /* Map both the text and data into the kernel page table */ 1365 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 1366 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 1367 pa_start + i * PAGE_SIZE, prot); 1368 1369 if (IS_ENABLED(CONFIG_RELOCATABLE)) 1370 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 1371 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 1372 1373 return 0; 1374 } 1375 core_initcall(map_entry_trampoline); 1376 #endif 1377 1378 /* 1379 * Declare the VMA areas for the kernel 1380 */ 1381 static void __init declare_kernel_vmas(void) 1382 { 1383 static struct vm_struct vmlinux_seg[KERNEL_SEGMENT_COUNT]; 1384 1385 declare_vma(&vmlinux_seg[0], _text, _etext, VM_NO_GUARD); 1386 declare_vma(&vmlinux_seg[1], __start_rodata, __inittext_begin, VM_NO_GUARD); 1387 declare_vma(&vmlinux_seg[2], __inittext_begin, __inittext_end, VM_NO_GUARD); 1388 declare_vma(&vmlinux_seg[3], __initdata_begin, __initdata_end, VM_NO_GUARD); 1389 declare_vma(&vmlinux_seg[4], _data, _end, 0); 1390 } 1391 1392 void __pi_map_range(phys_addr_t *pte, u64 start, u64 end, phys_addr_t pa, 1393 pgprot_t prot, int level, pte_t *tbl, bool may_use_cont, 1394 u64 va_offset); 1395 1396 static u8 idmap_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init, 1397 kpti_bbml2_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init; 1398 1399 static void __init create_idmap(void) 1400 { 1401 phys_addr_t start = __pa_symbol(__idmap_text_start); 1402 phys_addr_t end = __pa_symbol(__idmap_text_end); 1403 phys_addr_t ptep = __pa_symbol(idmap_ptes); 1404 1405 __pi_map_range(&ptep, start, end, start, PAGE_KERNEL_ROX, 1406 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false, 1407 __phys_to_virt(ptep) - ptep); 1408 1409 if (linear_map_requires_bbml2 || 1410 (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) && !arm64_use_ng_mappings)) { 1411 phys_addr_t pa = __pa_symbol(&idmap_kpti_bbml2_flag); 1412 1413 /* 1414 * The KPTI G-to-nG conversion code needs a read-write mapping 1415 * of its synchronization flag in the ID map. This is also used 1416 * when splitting the linear map to ptes if a secondary CPU 1417 * doesn't support bbml2. 1418 */ 1419 ptep = __pa_symbol(kpti_bbml2_ptes); 1420 __pi_map_range(&ptep, pa, pa + sizeof(u32), pa, PAGE_KERNEL, 1421 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false, 1422 __phys_to_virt(ptep) - ptep); 1423 } 1424 } 1425 1426 void __init paging_init(void) 1427 { 1428 map_mem(swapper_pg_dir); 1429 1430 memblock_allow_resize(); 1431 1432 create_idmap(); 1433 declare_kernel_vmas(); 1434 } 1435 1436 #ifdef CONFIG_MEMORY_HOTPLUG 1437 static void free_hotplug_page_range(struct page *page, size_t size, 1438 struct vmem_altmap *altmap) 1439 { 1440 if (altmap) { 1441 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 1442 } else { 1443 WARN_ON(PageReserved(page)); 1444 __free_pages(page, get_order(size)); 1445 } 1446 } 1447 1448 static void free_hotplug_pgtable_page(struct page *page) 1449 { 1450 pagetable_dtor(page_ptdesc(page)); 1451 free_hotplug_page_range(page, PAGE_SIZE, NULL); 1452 } 1453 1454 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 1455 unsigned long floor, unsigned long ceiling, 1456 unsigned long mask) 1457 { 1458 start &= mask; 1459 if (start < floor) 1460 return false; 1461 1462 if (ceiling) { 1463 ceiling &= mask; 1464 if (!ceiling) 1465 return false; 1466 } 1467 1468 if (end - 1 > ceiling - 1) 1469 return false; 1470 return true; 1471 } 1472 1473 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 1474 unsigned long end, bool free_mapped, 1475 struct vmem_altmap *altmap) 1476 { 1477 pte_t *ptep, pte; 1478 1479 do { 1480 ptep = pte_offset_kernel(pmdp, addr); 1481 pte = __ptep_get(ptep); 1482 if (pte_none(pte)) 1483 continue; 1484 1485 WARN_ON(!pte_present(pte)); 1486 __pte_clear(&init_mm, addr, ptep); 1487 if (free_mapped) { 1488 /* CONT blocks are not supported in the vmemmap */ 1489 WARN_ON(pte_cont(pte)); 1490 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 1491 free_hotplug_page_range(pte_page(pte), 1492 PAGE_SIZE, altmap); 1493 } 1494 /* unmap_hotplug_range() flushes TLB for !free_mapped */ 1495 } while (addr += PAGE_SIZE, addr < end); 1496 } 1497 1498 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 1499 unsigned long end, bool free_mapped, 1500 struct vmem_altmap *altmap) 1501 { 1502 unsigned long next; 1503 pmd_t *pmdp, pmd; 1504 1505 do { 1506 next = pmd_addr_end(addr, end); 1507 pmdp = pmd_offset(pudp, addr); 1508 pmd = READ_ONCE(*pmdp); 1509 if (pmd_none(pmd)) 1510 continue; 1511 1512 WARN_ON(!pmd_present(pmd)); 1513 if (pmd_sect(pmd)) { 1514 pmd_clear(pmdp); 1515 if (free_mapped) { 1516 /* CONT blocks are not supported in the vmemmap */ 1517 WARN_ON(pmd_cont(pmd)); 1518 flush_tlb_kernel_range(addr, addr + PMD_SIZE); 1519 free_hotplug_page_range(pmd_page(pmd), 1520 PMD_SIZE, altmap); 1521 } 1522 /* unmap_hotplug_range() flushes TLB for !free_mapped */ 1523 continue; 1524 } 1525 WARN_ON(!pmd_table(pmd)); 1526 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 1527 } while (addr = next, addr < end); 1528 } 1529 1530 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 1531 unsigned long end, bool free_mapped, 1532 struct vmem_altmap *altmap) 1533 { 1534 unsigned long next; 1535 pud_t *pudp, pud; 1536 1537 do { 1538 next = pud_addr_end(addr, end); 1539 pudp = pud_offset(p4dp, addr); 1540 pud = READ_ONCE(*pudp); 1541 if (pud_none(pud)) 1542 continue; 1543 1544 WARN_ON(!pud_present(pud)); 1545 if (pud_sect(pud)) { 1546 pud_clear(pudp); 1547 if (free_mapped) { 1548 flush_tlb_kernel_range(addr, addr + PUD_SIZE); 1549 free_hotplug_page_range(pud_page(pud), 1550 PUD_SIZE, altmap); 1551 } 1552 /* unmap_hotplug_range() flushes TLB for !free_mapped */ 1553 continue; 1554 } 1555 WARN_ON(!pud_table(pud)); 1556 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 1557 } while (addr = next, addr < end); 1558 } 1559 1560 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 1561 unsigned long end, bool free_mapped, 1562 struct vmem_altmap *altmap) 1563 { 1564 unsigned long next; 1565 p4d_t *p4dp, p4d; 1566 1567 do { 1568 next = p4d_addr_end(addr, end); 1569 p4dp = p4d_offset(pgdp, addr); 1570 p4d = READ_ONCE(*p4dp); 1571 if (p4d_none(p4d)) 1572 continue; 1573 1574 WARN_ON(!p4d_present(p4d)); 1575 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 1576 } while (addr = next, addr < end); 1577 } 1578 1579 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 1580 bool free_mapped, struct vmem_altmap *altmap) 1581 { 1582 unsigned long start = addr; 1583 unsigned long next; 1584 pgd_t *pgdp, pgd; 1585 1586 /* 1587 * altmap can only be used as vmemmap mapping backing memory. 1588 * In case the backing memory itself is not being freed, then 1589 * altmap is irrelevant. Warn about this inconsistency when 1590 * encountered. 1591 */ 1592 WARN_ON(!free_mapped && altmap); 1593 1594 do { 1595 next = pgd_addr_end(addr, end); 1596 pgdp = pgd_offset_k(addr); 1597 pgd = READ_ONCE(*pgdp); 1598 if (pgd_none(pgd)) 1599 continue; 1600 1601 WARN_ON(!pgd_present(pgd)); 1602 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 1603 } while (addr = next, addr < end); 1604 1605 if (!free_mapped) 1606 flush_tlb_kernel_range(start, end); 1607 } 1608 1609 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 1610 unsigned long end, unsigned long floor, 1611 unsigned long ceiling) 1612 { 1613 pte_t *ptep, pte; 1614 unsigned long i, start = addr; 1615 1616 do { 1617 ptep = pte_offset_kernel(pmdp, addr); 1618 pte = __ptep_get(ptep); 1619 1620 /* 1621 * This is just a sanity check here which verifies that 1622 * pte clearing has been done by earlier unmap loops. 1623 */ 1624 WARN_ON(!pte_none(pte)); 1625 } while (addr += PAGE_SIZE, addr < end); 1626 1627 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1628 return; 1629 1630 /* 1631 * Check whether we can free the pte page if the rest of the 1632 * entries are empty. Overlap with other regions have been 1633 * handled by the floor/ceiling check. 1634 */ 1635 ptep = pte_offset_kernel(pmdp, 0UL); 1636 for (i = 0; i < PTRS_PER_PTE; i++) { 1637 if (!pte_none(__ptep_get(&ptep[i]))) 1638 return; 1639 } 1640 1641 pmd_clear(pmdp); 1642 __flush_tlb_kernel_pgtable(start); 1643 free_hotplug_pgtable_page(virt_to_page(ptep)); 1644 } 1645 1646 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1647 unsigned long end, unsigned long floor, 1648 unsigned long ceiling) 1649 { 1650 pmd_t *pmdp, pmd; 1651 unsigned long i, next, start = addr; 1652 1653 do { 1654 next = pmd_addr_end(addr, end); 1655 pmdp = pmd_offset(pudp, addr); 1656 pmd = READ_ONCE(*pmdp); 1657 if (pmd_none(pmd)) 1658 continue; 1659 1660 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1661 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1662 } while (addr = next, addr < end); 1663 1664 if (CONFIG_PGTABLE_LEVELS <= 2) 1665 return; 1666 1667 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1668 return; 1669 1670 /* 1671 * Check whether we can free the pmd page if the rest of the 1672 * entries are empty. Overlap with other regions have been 1673 * handled by the floor/ceiling check. 1674 */ 1675 pmdp = pmd_offset(pudp, 0UL); 1676 for (i = 0; i < PTRS_PER_PMD; i++) { 1677 if (!pmd_none(READ_ONCE(pmdp[i]))) 1678 return; 1679 } 1680 1681 pud_clear(pudp); 1682 __flush_tlb_kernel_pgtable(start); 1683 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1684 } 1685 1686 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1687 unsigned long end, unsigned long floor, 1688 unsigned long ceiling) 1689 { 1690 pud_t *pudp, pud; 1691 unsigned long i, next, start = addr; 1692 1693 do { 1694 next = pud_addr_end(addr, end); 1695 pudp = pud_offset(p4dp, addr); 1696 pud = READ_ONCE(*pudp); 1697 if (pud_none(pud)) 1698 continue; 1699 1700 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1701 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1702 } while (addr = next, addr < end); 1703 1704 if (!pgtable_l4_enabled()) 1705 return; 1706 1707 if (!pgtable_range_aligned(start, end, floor, ceiling, P4D_MASK)) 1708 return; 1709 1710 /* 1711 * Check whether we can free the pud page if the rest of the 1712 * entries are empty. Overlap with other regions have been 1713 * handled by the floor/ceiling check. 1714 */ 1715 pudp = pud_offset(p4dp, 0UL); 1716 for (i = 0; i < PTRS_PER_PUD; i++) { 1717 if (!pud_none(READ_ONCE(pudp[i]))) 1718 return; 1719 } 1720 1721 p4d_clear(p4dp); 1722 __flush_tlb_kernel_pgtable(start); 1723 free_hotplug_pgtable_page(virt_to_page(pudp)); 1724 } 1725 1726 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1727 unsigned long end, unsigned long floor, 1728 unsigned long ceiling) 1729 { 1730 p4d_t *p4dp, p4d; 1731 unsigned long i, next, start = addr; 1732 1733 do { 1734 next = p4d_addr_end(addr, end); 1735 p4dp = p4d_offset(pgdp, addr); 1736 p4d = READ_ONCE(*p4dp); 1737 if (p4d_none(p4d)) 1738 continue; 1739 1740 WARN_ON(!p4d_present(p4d)); 1741 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1742 } while (addr = next, addr < end); 1743 1744 if (!pgtable_l5_enabled()) 1745 return; 1746 1747 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1748 return; 1749 1750 /* 1751 * Check whether we can free the p4d page if the rest of the 1752 * entries are empty. Overlap with other regions have been 1753 * handled by the floor/ceiling check. 1754 */ 1755 p4dp = p4d_offset(pgdp, 0UL); 1756 for (i = 0; i < PTRS_PER_P4D; i++) { 1757 if (!p4d_none(READ_ONCE(p4dp[i]))) 1758 return; 1759 } 1760 1761 pgd_clear(pgdp); 1762 __flush_tlb_kernel_pgtable(start); 1763 free_hotplug_pgtable_page(virt_to_page(p4dp)); 1764 } 1765 1766 static void free_empty_tables(unsigned long addr, unsigned long end, 1767 unsigned long floor, unsigned long ceiling) 1768 { 1769 unsigned long next; 1770 pgd_t *pgdp, pgd; 1771 1772 do { 1773 next = pgd_addr_end(addr, end); 1774 pgdp = pgd_offset_k(addr); 1775 pgd = READ_ONCE(*pgdp); 1776 if (pgd_none(pgd)) 1777 continue; 1778 1779 WARN_ON(!pgd_present(pgd)); 1780 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1781 } while (addr = next, addr < end); 1782 } 1783 #endif 1784 1785 void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node, 1786 unsigned long addr, unsigned long next) 1787 { 1788 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1789 } 1790 1791 int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node, 1792 unsigned long addr, unsigned long next) 1793 { 1794 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1795 1796 return pmd_sect(READ_ONCE(*pmdp)); 1797 } 1798 1799 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1800 struct vmem_altmap *altmap) 1801 { 1802 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1803 /* [start, end] should be within one section */ 1804 WARN_ON_ONCE(end - start > PAGES_PER_SECTION * sizeof(struct page)); 1805 1806 if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES) || 1807 (end - start < PAGES_PER_SECTION * sizeof(struct page))) 1808 return vmemmap_populate_basepages(start, end, node, altmap); 1809 else 1810 return vmemmap_populate_hugepages(start, end, node, altmap); 1811 } 1812 1813 #ifdef CONFIG_MEMORY_HOTPLUG 1814 void vmemmap_free(unsigned long start, unsigned long end, 1815 struct vmem_altmap *altmap) 1816 { 1817 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1818 1819 unmap_hotplug_range(start, end, true, altmap); 1820 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1821 } 1822 #endif /* CONFIG_MEMORY_HOTPLUG */ 1823 1824 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1825 { 1826 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1827 1828 /* Only allow permission changes for now */ 1829 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1830 pud_val(new_pud))) 1831 return 0; 1832 1833 VM_BUG_ON(phys & ~PUD_MASK); 1834 set_pud(pudp, new_pud); 1835 return 1; 1836 } 1837 1838 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1839 { 1840 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1841 1842 /* Only allow permission changes for now */ 1843 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1844 pmd_val(new_pmd))) 1845 return 0; 1846 1847 VM_BUG_ON(phys & ~PMD_MASK); 1848 set_pmd(pmdp, new_pmd); 1849 return 1; 1850 } 1851 1852 #ifndef __PAGETABLE_P4D_FOLDED 1853 void p4d_clear_huge(p4d_t *p4dp) 1854 { 1855 } 1856 #endif 1857 1858 int pud_clear_huge(pud_t *pudp) 1859 { 1860 if (!pud_sect(READ_ONCE(*pudp))) 1861 return 0; 1862 pud_clear(pudp); 1863 return 1; 1864 } 1865 1866 int pmd_clear_huge(pmd_t *pmdp) 1867 { 1868 if (!pmd_sect(READ_ONCE(*pmdp))) 1869 return 0; 1870 pmd_clear(pmdp); 1871 return 1; 1872 } 1873 1874 static int __pmd_free_pte_page(pmd_t *pmdp, unsigned long addr, 1875 bool acquire_mmap_lock) 1876 { 1877 pte_t *table; 1878 pmd_t pmd; 1879 1880 pmd = READ_ONCE(*pmdp); 1881 1882 if (!pmd_table(pmd)) { 1883 VM_WARN_ON(1); 1884 return 1; 1885 } 1886 1887 /* See comment in pud_free_pmd_page for static key logic */ 1888 table = pte_offset_kernel(pmdp, addr); 1889 pmd_clear(pmdp); 1890 __flush_tlb_kernel_pgtable(addr); 1891 if (static_branch_unlikely(&arm64_ptdump_lock_key) && acquire_mmap_lock) { 1892 mmap_read_lock(&init_mm); 1893 mmap_read_unlock(&init_mm); 1894 } 1895 1896 pte_free_kernel(NULL, table); 1897 return 1; 1898 } 1899 1900 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1901 { 1902 /* If ptdump is walking the pagetables, acquire init_mm.mmap_lock */ 1903 return __pmd_free_pte_page(pmdp, addr, /* acquire_mmap_lock = */ true); 1904 } 1905 1906 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1907 { 1908 pmd_t *table; 1909 pmd_t *pmdp; 1910 pud_t pud; 1911 unsigned long next, end; 1912 1913 pud = READ_ONCE(*pudp); 1914 1915 if (!pud_table(pud)) { 1916 VM_WARN_ON(1); 1917 return 1; 1918 } 1919 1920 table = pmd_offset(pudp, addr); 1921 1922 /* 1923 * Our objective is to prevent ptdump from reading a PMD table which has 1924 * been freed. In this race, if pud_free_pmd_page observes the key on 1925 * (which got flipped by ptdump) then the mmap lock sequence here will, 1926 * as a result of the mmap write lock/unlock sequence in ptdump, give 1927 * us the correct synchronization. If not, this means that ptdump has 1928 * yet not started walking the pagetables - the sequence of barriers 1929 * issued by __flush_tlb_kernel_pgtable() guarantees that ptdump will 1930 * observe an empty PUD. 1931 */ 1932 pud_clear(pudp); 1933 __flush_tlb_kernel_pgtable(addr); 1934 if (static_branch_unlikely(&arm64_ptdump_lock_key)) { 1935 mmap_read_lock(&init_mm); 1936 mmap_read_unlock(&init_mm); 1937 } 1938 1939 pmdp = table; 1940 next = addr; 1941 end = addr + PUD_SIZE; 1942 do { 1943 if (pmd_present(pmdp_get(pmdp))) 1944 /* 1945 * PMD has been isolated, so ptdump won't see it. No 1946 * need to acquire init_mm.mmap_lock. 1947 */ 1948 __pmd_free_pte_page(pmdp, next, /* acquire_mmap_lock = */ false); 1949 } while (pmdp++, next += PMD_SIZE, next != end); 1950 1951 pmd_free(NULL, table); 1952 return 1; 1953 } 1954 1955 #ifdef CONFIG_MEMORY_HOTPLUG 1956 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1957 { 1958 unsigned long end = start + size; 1959 1960 WARN_ON(pgdir != init_mm.pgd); 1961 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1962 1963 unmap_hotplug_range(start, end, false, NULL); 1964 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1965 } 1966 1967 struct range arch_get_mappable_range(void) 1968 { 1969 struct range mhp_range; 1970 phys_addr_t start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1971 phys_addr_t end_linear_pa = __pa(PAGE_END - 1); 1972 1973 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1974 /* 1975 * Check for a wrap, it is possible because of randomized linear 1976 * mapping the start physical address is actually bigger than 1977 * the end physical address. In this case set start to zero 1978 * because [0, end_linear_pa] range must still be able to cover 1979 * all addressable physical addresses. 1980 */ 1981 if (start_linear_pa > end_linear_pa) 1982 start_linear_pa = 0; 1983 } 1984 1985 WARN_ON(start_linear_pa > end_linear_pa); 1986 1987 /* 1988 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1989 * accommodating both its ends but excluding PAGE_END. Max physical 1990 * range which can be mapped inside this linear mapping range, must 1991 * also be derived from its end points. 1992 */ 1993 mhp_range.start = start_linear_pa; 1994 mhp_range.end = end_linear_pa; 1995 1996 return mhp_range; 1997 } 1998 1999 int arch_add_memory(int nid, u64 start, u64 size, 2000 struct mhp_params *params) 2001 { 2002 int ret, flags = NO_EXEC_MAPPINGS; 2003 2004 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 2005 2006 if (force_pte_mapping()) 2007 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 2008 2009 ret = __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 2010 size, params->pgprot, pgd_pgtable_alloc_init_mm, 2011 flags); 2012 if (ret) 2013 goto err; 2014 2015 memblock_clear_nomap(start, size); 2016 2017 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 2018 params); 2019 if (ret) 2020 goto err; 2021 2022 /* Address of hotplugged memory can be smaller */ 2023 max_pfn = max(max_pfn, PFN_UP(start + size)); 2024 max_low_pfn = max_pfn; 2025 2026 return 0; 2027 2028 err: 2029 __remove_pgd_mapping(swapper_pg_dir, 2030 __phys_to_virt(start), size); 2031 return ret; 2032 } 2033 2034 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 2035 { 2036 unsigned long start_pfn = start >> PAGE_SHIFT; 2037 unsigned long nr_pages = size >> PAGE_SHIFT; 2038 2039 __remove_pages(start_pfn, nr_pages, altmap); 2040 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 2041 } 2042 2043 /* 2044 * This memory hotplug notifier helps prevent boot memory from being 2045 * inadvertently removed as it blocks pfn range offlining process in 2046 * __offline_pages(). Hence this prevents both offlining as well as 2047 * removal process for boot memory which is initially always online. 2048 * In future if and when boot memory could be removed, this notifier 2049 * should be dropped and free_hotplug_page_range() should handle any 2050 * reserved pages allocated during boot. 2051 */ 2052 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 2053 unsigned long action, void *data) 2054 { 2055 struct mem_section *ms; 2056 struct memory_notify *arg = data; 2057 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 2058 unsigned long pfn = arg->start_pfn; 2059 2060 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 2061 return NOTIFY_OK; 2062 2063 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 2064 unsigned long start = PFN_PHYS(pfn); 2065 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 2066 2067 ms = __pfn_to_section(pfn); 2068 if (!early_section(ms)) 2069 continue; 2070 2071 if (action == MEM_GOING_OFFLINE) { 2072 /* 2073 * Boot memory removal is not supported. Prevent 2074 * it via blocking any attempted offline request 2075 * for the boot memory and just report it. 2076 */ 2077 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 2078 return NOTIFY_BAD; 2079 } else if (action == MEM_OFFLINE) { 2080 /* 2081 * This should have never happened. Boot memory 2082 * offlining should have been prevented by this 2083 * very notifier. Probably some memory removal 2084 * procedure might have changed which would then 2085 * require further debug. 2086 */ 2087 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 2088 2089 /* 2090 * Core memory hotplug does not process a return 2091 * code from the notifier for MEM_OFFLINE events. 2092 * The error condition has been reported. Return 2093 * from here as if ignored. 2094 */ 2095 return NOTIFY_DONE; 2096 } 2097 } 2098 return NOTIFY_OK; 2099 } 2100 2101 static struct notifier_block prevent_bootmem_remove_nb = { 2102 .notifier_call = prevent_bootmem_remove_notifier, 2103 }; 2104 2105 /* 2106 * This ensures that boot memory sections on the platform are online 2107 * from early boot. Memory sections could not be prevented from being 2108 * offlined, unless for some reason they are not online to begin with. 2109 * This helps validate the basic assumption on which the above memory 2110 * event notifier works to prevent boot memory section offlining and 2111 * its possible removal. 2112 */ 2113 static void validate_bootmem_online(void) 2114 { 2115 phys_addr_t start, end, addr; 2116 struct mem_section *ms; 2117 u64 i; 2118 2119 /* 2120 * Scanning across all memblock might be expensive 2121 * on some big memory systems. Hence enable this 2122 * validation only with DEBUG_VM. 2123 */ 2124 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 2125 return; 2126 2127 for_each_mem_range(i, &start, &end) { 2128 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 2129 ms = __pfn_to_section(PHYS_PFN(addr)); 2130 2131 /* 2132 * All memory ranges in the system at this point 2133 * should have been marked as early sections. 2134 */ 2135 WARN_ON(!early_section(ms)); 2136 2137 /* 2138 * Memory notifier mechanism here to prevent boot 2139 * memory offlining depends on the fact that each 2140 * early section memory on the system is initially 2141 * online. Otherwise a given memory section which 2142 * is already offline will be overlooked and can 2143 * be removed completely. Call out such sections. 2144 */ 2145 if (!online_section(ms)) 2146 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 2147 addr, addr + (1UL << PA_SECTION_SHIFT)); 2148 } 2149 } 2150 } 2151 2152 static int __init prevent_bootmem_remove_init(void) 2153 { 2154 int ret = 0; 2155 2156 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 2157 return ret; 2158 2159 validate_bootmem_online(); 2160 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 2161 if (ret) 2162 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 2163 2164 return ret; 2165 } 2166 early_initcall(prevent_bootmem_remove_init); 2167 #endif 2168 2169 pte_t modify_prot_start_ptes(struct vm_area_struct *vma, unsigned long addr, 2170 pte_t *ptep, unsigned int nr) 2171 { 2172 pte_t pte = get_and_clear_ptes(vma->vm_mm, addr, ptep, nr); 2173 2174 if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) { 2175 /* 2176 * Break-before-make (BBM) is required for all user space mappings 2177 * when the permission changes from executable to non-executable 2178 * in cases where cpu is affected with errata #2645198. 2179 */ 2180 if (pte_accessible(vma->vm_mm, pte) && pte_user_exec(pte)) 2181 __flush_tlb_range(vma, addr, nr * PAGE_SIZE, 2182 PAGE_SIZE, true, 3); 2183 } 2184 2185 return pte; 2186 } 2187 2188 pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) 2189 { 2190 return modify_prot_start_ptes(vma, addr, ptep, 1); 2191 } 2192 2193 void modify_prot_commit_ptes(struct vm_area_struct *vma, unsigned long addr, 2194 pte_t *ptep, pte_t old_pte, pte_t pte, 2195 unsigned int nr) 2196 { 2197 set_ptes(vma->vm_mm, addr, ptep, pte, nr); 2198 } 2199 2200 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, 2201 pte_t old_pte, pte_t pte) 2202 { 2203 modify_prot_commit_ptes(vma, addr, ptep, old_pte, pte, 1); 2204 } 2205 2206 /* 2207 * Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD, 2208 * avoiding the possibility of conflicting TLB entries being allocated. 2209 */ 2210 void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp) 2211 { 2212 typedef void (ttbr_replace_func)(phys_addr_t); 2213 extern ttbr_replace_func idmap_cpu_replace_ttbr1; 2214 ttbr_replace_func *replace_phys; 2215 unsigned long daif; 2216 2217 /* phys_to_ttbr() zeros lower 2 bits of ttbr with 52-bit PA */ 2218 phys_addr_t ttbr1 = phys_to_ttbr(virt_to_phys(pgdp)); 2219 2220 if (cnp) 2221 ttbr1 |= TTBR_CNP_BIT; 2222 2223 replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1); 2224 2225 cpu_install_idmap(); 2226 2227 /* 2228 * We really don't want to take *any* exceptions while TTBR1 is 2229 * in the process of being replaced so mask everything. 2230 */ 2231 daif = local_daif_save(); 2232 replace_phys(ttbr1); 2233 local_daif_restore(daif); 2234 2235 cpu_uninstall_idmap(); 2236 } 2237 2238 #ifdef CONFIG_ARCH_HAS_PKEYS 2239 int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) 2240 { 2241 u64 new_por; 2242 u64 old_por; 2243 2244 if (!system_supports_poe()) 2245 return -ENOSPC; 2246 2247 /* 2248 * This code should only be called with valid 'pkey' 2249 * values originating from in-kernel users. Complain 2250 * if a bad value is observed. 2251 */ 2252 if (WARN_ON_ONCE(pkey >= arch_max_pkey())) 2253 return -EINVAL; 2254 2255 /* Set the bits we need in POR: */ 2256 new_por = POE_RWX; 2257 if (init_val & PKEY_DISABLE_WRITE) 2258 new_por &= ~POE_W; 2259 if (init_val & PKEY_DISABLE_ACCESS) 2260 new_por &= ~POE_RW; 2261 if (init_val & PKEY_DISABLE_READ) 2262 new_por &= ~POE_R; 2263 if (init_val & PKEY_DISABLE_EXECUTE) 2264 new_por &= ~POE_X; 2265 2266 /* Shift the bits in to the correct place in POR for pkey: */ 2267 new_por = POR_ELx_PERM_PREP(pkey, new_por); 2268 2269 /* Get old POR and mask off any old bits in place: */ 2270 old_por = read_sysreg_s(SYS_POR_EL0); 2271 old_por &= ~(POE_MASK << POR_ELx_PERM_SHIFT(pkey)); 2272 2273 /* Write old part along with new part: */ 2274 write_sysreg_s(old_por | new_por, SYS_POR_EL0); 2275 2276 return 0; 2277 } 2278 #endif