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/memory.h> 21 #include <linux/fs.h> 22 #include <linux/io.h> 23 #include <linux/mm.h> 24 #include <linux/vmalloc.h> 25 26 #include <asm/barrier.h> 27 #include <asm/cputype.h> 28 #include <asm/fixmap.h> 29 #include <asm/kasan.h> 30 #include <asm/kernel-pgtable.h> 31 #include <asm/sections.h> 32 #include <asm/setup.h> 33 #include <linux/sizes.h> 34 #include <asm/tlb.h> 35 #include <asm/mmu_context.h> 36 #include <asm/ptdump.h> 37 #include <asm/tlbflush.h> 38 #include <asm/pgalloc.h> 39 40 #define NO_BLOCK_MAPPINGS BIT(0) 41 #define NO_CONT_MAPPINGS BIT(1) 42 43 u64 idmap_t0sz = TCR_T0SZ(VA_BITS); 44 u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; 45 46 u64 __section(".mmuoff.data.write") vabits_actual; 47 EXPORT_SYMBOL(vabits_actual); 48 49 u64 kimage_voffset __ro_after_init; 50 EXPORT_SYMBOL(kimage_voffset); 51 52 /* 53 * Empty_zero_page is a special page that is used for zero-initialized data 54 * and COW. 55 */ 56 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 57 EXPORT_SYMBOL(empty_zero_page); 58 59 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; 60 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; 61 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; 62 63 static DEFINE_SPINLOCK(swapper_pgdir_lock); 64 65 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 66 { 67 pgd_t *fixmap_pgdp; 68 69 spin_lock(&swapper_pgdir_lock); 70 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 71 WRITE_ONCE(*fixmap_pgdp, pgd); 72 /* 73 * We need dsb(ishst) here to ensure the page-table-walker sees 74 * our new entry before set_p?d() returns. The fixmap's 75 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 76 */ 77 pgd_clear_fixmap(); 78 spin_unlock(&swapper_pgdir_lock); 79 } 80 81 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 82 unsigned long size, pgprot_t vma_prot) 83 { 84 if (!pfn_valid(pfn)) 85 return pgprot_noncached(vma_prot); 86 else if (file->f_flags & O_SYNC) 87 return pgprot_writecombine(vma_prot); 88 return vma_prot; 89 } 90 EXPORT_SYMBOL(phys_mem_access_prot); 91 92 static phys_addr_t __init early_pgtable_alloc(int shift) 93 { 94 phys_addr_t phys; 95 void *ptr; 96 97 phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); 98 if (!phys) 99 panic("Failed to allocate page table page\n"); 100 101 /* 102 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE 103 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise 104 * any level of table. 105 */ 106 ptr = pte_set_fixmap(phys); 107 108 memset(ptr, 0, PAGE_SIZE); 109 110 /* 111 * Implicit barriers also ensure the zeroed page is visible to the page 112 * table walker 113 */ 114 pte_clear_fixmap(); 115 116 return phys; 117 } 118 119 static bool pgattr_change_is_safe(u64 old, u64 new) 120 { 121 /* 122 * The following mapping attributes may be updated in live 123 * kernel mappings without the need for break-before-make. 124 */ 125 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 126 127 /* creating or taking down mappings is always safe */ 128 if (old == 0 || new == 0) 129 return true; 130 131 /* live contiguous mappings may not be manipulated at all */ 132 if ((old | new) & PTE_CONT) 133 return false; 134 135 /* Transitioning from Non-Global to Global is unsafe */ 136 if (old & ~new & PTE_NG) 137 return false; 138 139 /* 140 * Changing the memory type between Normal and Normal-Tagged is safe 141 * since Tagged is considered a permission attribute from the 142 * mismatched attribute aliases perspective. 143 */ 144 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 145 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 146 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 147 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 148 mask |= PTE_ATTRINDX_MASK; 149 150 return ((old ^ new) & ~mask) == 0; 151 } 152 153 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 154 phys_addr_t phys, pgprot_t prot) 155 { 156 pte_t *ptep; 157 158 ptep = pte_set_fixmap_offset(pmdp, addr); 159 do { 160 pte_t old_pte = READ_ONCE(*ptep); 161 162 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 163 164 /* 165 * After the PTE entry has been populated once, we 166 * only allow updates to the permission attributes. 167 */ 168 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 169 READ_ONCE(pte_val(*ptep)))); 170 171 phys += PAGE_SIZE; 172 } while (ptep++, addr += PAGE_SIZE, addr != end); 173 174 pte_clear_fixmap(); 175 } 176 177 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 178 unsigned long end, phys_addr_t phys, 179 pgprot_t prot, 180 phys_addr_t (*pgtable_alloc)(int), 181 int flags) 182 { 183 unsigned long next; 184 pmd_t pmd = READ_ONCE(*pmdp); 185 186 BUG_ON(pmd_sect(pmd)); 187 if (pmd_none(pmd)) { 188 phys_addr_t pte_phys; 189 BUG_ON(!pgtable_alloc); 190 pte_phys = pgtable_alloc(PAGE_SHIFT); 191 __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE); 192 pmd = READ_ONCE(*pmdp); 193 } 194 BUG_ON(pmd_bad(pmd)); 195 196 do { 197 pgprot_t __prot = prot; 198 199 next = pte_cont_addr_end(addr, end); 200 201 /* use a contiguous mapping if the range is suitably aligned */ 202 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 203 (flags & NO_CONT_MAPPINGS) == 0) 204 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 205 206 init_pte(pmdp, addr, next, phys, __prot); 207 208 phys += next - addr; 209 } while (addr = next, addr != end); 210 } 211 212 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 213 phys_addr_t phys, pgprot_t prot, 214 phys_addr_t (*pgtable_alloc)(int), int flags) 215 { 216 unsigned long next; 217 pmd_t *pmdp; 218 219 pmdp = pmd_set_fixmap_offset(pudp, addr); 220 do { 221 pmd_t old_pmd = READ_ONCE(*pmdp); 222 223 next = pmd_addr_end(addr, end); 224 225 /* try section mapping first */ 226 if (((addr | next | phys) & ~SECTION_MASK) == 0 && 227 (flags & NO_BLOCK_MAPPINGS) == 0) { 228 pmd_set_huge(pmdp, phys, prot); 229 230 /* 231 * After the PMD entry has been populated once, we 232 * only allow updates to the permission attributes. 233 */ 234 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 235 READ_ONCE(pmd_val(*pmdp)))); 236 } else { 237 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 238 pgtable_alloc, flags); 239 240 BUG_ON(pmd_val(old_pmd) != 0 && 241 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 242 } 243 phys += next - addr; 244 } while (pmdp++, addr = next, addr != end); 245 246 pmd_clear_fixmap(); 247 } 248 249 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 250 unsigned long end, phys_addr_t phys, 251 pgprot_t prot, 252 phys_addr_t (*pgtable_alloc)(int), int flags) 253 { 254 unsigned long next; 255 pud_t pud = READ_ONCE(*pudp); 256 257 /* 258 * Check for initial section mappings in the pgd/pud. 259 */ 260 BUG_ON(pud_sect(pud)); 261 if (pud_none(pud)) { 262 phys_addr_t pmd_phys; 263 BUG_ON(!pgtable_alloc); 264 pmd_phys = pgtable_alloc(PMD_SHIFT); 265 __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE); 266 pud = READ_ONCE(*pudp); 267 } 268 BUG_ON(pud_bad(pud)); 269 270 do { 271 pgprot_t __prot = prot; 272 273 next = pmd_cont_addr_end(addr, end); 274 275 /* use a contiguous mapping if the range is suitably aligned */ 276 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 277 (flags & NO_CONT_MAPPINGS) == 0) 278 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 279 280 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 281 282 phys += next - addr; 283 } while (addr = next, addr != end); 284 } 285 286 static inline bool use_1G_block(unsigned long addr, unsigned long next, 287 unsigned long phys) 288 { 289 if (PAGE_SHIFT != 12) 290 return false; 291 292 if (((addr | next | phys) & ~PUD_MASK) != 0) 293 return false; 294 295 return true; 296 } 297 298 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 299 phys_addr_t phys, pgprot_t prot, 300 phys_addr_t (*pgtable_alloc)(int), 301 int flags) 302 { 303 unsigned long next; 304 pud_t *pudp; 305 p4d_t *p4dp = p4d_offset(pgdp, addr); 306 p4d_t p4d = READ_ONCE(*p4dp); 307 308 if (p4d_none(p4d)) { 309 phys_addr_t pud_phys; 310 BUG_ON(!pgtable_alloc); 311 pud_phys = pgtable_alloc(PUD_SHIFT); 312 __p4d_populate(p4dp, pud_phys, PUD_TYPE_TABLE); 313 p4d = READ_ONCE(*p4dp); 314 } 315 BUG_ON(p4d_bad(p4d)); 316 317 pudp = pud_set_fixmap_offset(p4dp, addr); 318 do { 319 pud_t old_pud = READ_ONCE(*pudp); 320 321 next = pud_addr_end(addr, end); 322 323 /* 324 * For 4K granule only, attempt to put down a 1GB block 325 */ 326 if (use_1G_block(addr, next, phys) && 327 (flags & NO_BLOCK_MAPPINGS) == 0) { 328 pud_set_huge(pudp, phys, prot); 329 330 /* 331 * After the PUD entry has been populated once, we 332 * only allow updates to the permission attributes. 333 */ 334 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 335 READ_ONCE(pud_val(*pudp)))); 336 } else { 337 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 338 pgtable_alloc, flags); 339 340 BUG_ON(pud_val(old_pud) != 0 && 341 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 342 } 343 phys += next - addr; 344 } while (pudp++, addr = next, addr != end); 345 346 pud_clear_fixmap(); 347 } 348 349 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 350 unsigned long virt, phys_addr_t size, 351 pgprot_t prot, 352 phys_addr_t (*pgtable_alloc)(int), 353 int flags) 354 { 355 unsigned long addr, end, next; 356 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 357 358 /* 359 * If the virtual and physical address don't have the same offset 360 * within a page, we cannot map the region as the caller expects. 361 */ 362 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 363 return; 364 365 phys &= PAGE_MASK; 366 addr = virt & PAGE_MASK; 367 end = PAGE_ALIGN(virt + size); 368 369 do { 370 next = pgd_addr_end(addr, end); 371 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 372 flags); 373 phys += next - addr; 374 } while (pgdp++, addr = next, addr != end); 375 } 376 377 static phys_addr_t __pgd_pgtable_alloc(int shift) 378 { 379 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 380 BUG_ON(!ptr); 381 382 /* Ensure the zeroed page is visible to the page table walker */ 383 dsb(ishst); 384 return __pa(ptr); 385 } 386 387 static phys_addr_t pgd_pgtable_alloc(int shift) 388 { 389 phys_addr_t pa = __pgd_pgtable_alloc(shift); 390 391 /* 392 * Call proper page table ctor in case later we need to 393 * call core mm functions like apply_to_page_range() on 394 * this pre-allocated page table. 395 * 396 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 397 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 398 */ 399 if (shift == PAGE_SHIFT) 400 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 401 else if (shift == PMD_SHIFT) 402 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 403 404 return pa; 405 } 406 407 /* 408 * This function can only be used to modify existing table entries, 409 * without allocating new levels of table. Note that this permits the 410 * creation of new section or page entries. 411 */ 412 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 413 phys_addr_t size, pgprot_t prot) 414 { 415 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 416 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 417 &phys, virt); 418 return; 419 } 420 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 421 NO_CONT_MAPPINGS); 422 } 423 424 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 425 unsigned long virt, phys_addr_t size, 426 pgprot_t prot, bool page_mappings_only) 427 { 428 int flags = 0; 429 430 BUG_ON(mm == &init_mm); 431 432 if (page_mappings_only) 433 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 434 435 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 436 pgd_pgtable_alloc, flags); 437 } 438 439 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 440 phys_addr_t size, pgprot_t prot) 441 { 442 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 443 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 444 &phys, virt); 445 return; 446 } 447 448 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 449 NO_CONT_MAPPINGS); 450 451 /* flush the TLBs after updating live kernel mappings */ 452 flush_tlb_kernel_range(virt, virt + size); 453 } 454 455 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 456 phys_addr_t end, pgprot_t prot, int flags) 457 { 458 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 459 prot, early_pgtable_alloc, flags); 460 } 461 462 void __init mark_linear_text_alias_ro(void) 463 { 464 /* 465 * Remove the write permissions from the linear alias of .text/.rodata 466 */ 467 update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text), 468 (unsigned long)__init_begin - (unsigned long)_text, 469 PAGE_KERNEL_RO); 470 } 471 472 static void __init map_mem(pgd_t *pgdp) 473 { 474 phys_addr_t kernel_start = __pa_symbol(_text); 475 phys_addr_t kernel_end = __pa_symbol(__init_begin); 476 phys_addr_t start, end; 477 int flags = 0; 478 u64 i; 479 480 if (rodata_full || debug_pagealloc_enabled()) 481 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 482 483 /* 484 * Take care not to create a writable alias for the 485 * read-only text and rodata sections of the kernel image. 486 * So temporarily mark them as NOMAP to skip mappings in 487 * the following for-loop 488 */ 489 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 490 #ifdef CONFIG_KEXEC_CORE 491 if (crashk_res.end) 492 memblock_mark_nomap(crashk_res.start, 493 resource_size(&crashk_res)); 494 #endif 495 496 /* map all the memory banks */ 497 for_each_mem_range(i, &start, &end) { 498 if (start >= end) 499 break; 500 /* 501 * The linear map must allow allocation tags reading/writing 502 * if MTE is present. Otherwise, it has the same attributes as 503 * PAGE_KERNEL. 504 */ 505 __map_memblock(pgdp, start, end, PAGE_KERNEL_TAGGED, flags); 506 } 507 508 /* 509 * Map the linear alias of the [_text, __init_begin) interval 510 * as non-executable now, and remove the write permission in 511 * mark_linear_text_alias_ro() below (which will be called after 512 * alternative patching has completed). This makes the contents 513 * of the region accessible to subsystems such as hibernate, 514 * but protects it from inadvertent modification or execution. 515 * Note that contiguous mappings cannot be remapped in this way, 516 * so we should avoid them here. 517 */ 518 __map_memblock(pgdp, kernel_start, kernel_end, 519 PAGE_KERNEL, NO_CONT_MAPPINGS); 520 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 521 522 #ifdef CONFIG_KEXEC_CORE 523 /* 524 * Use page-level mappings here so that we can shrink the region 525 * in page granularity and put back unused memory to buddy system 526 * through /sys/kernel/kexec_crash_size interface. 527 */ 528 if (crashk_res.end) { 529 __map_memblock(pgdp, crashk_res.start, crashk_res.end + 1, 530 PAGE_KERNEL, 531 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 532 memblock_clear_nomap(crashk_res.start, 533 resource_size(&crashk_res)); 534 } 535 #endif 536 } 537 538 void mark_rodata_ro(void) 539 { 540 unsigned long section_size; 541 542 /* 543 * mark .rodata as read only. Use __init_begin rather than __end_rodata 544 * to cover NOTES and EXCEPTION_TABLE. 545 */ 546 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 547 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 548 section_size, PAGE_KERNEL_RO); 549 550 debug_checkwx(); 551 } 552 553 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 554 pgprot_t prot, struct vm_struct *vma, 555 int flags, unsigned long vm_flags) 556 { 557 phys_addr_t pa_start = __pa_symbol(va_start); 558 unsigned long size = va_end - va_start; 559 560 BUG_ON(!PAGE_ALIGNED(pa_start)); 561 BUG_ON(!PAGE_ALIGNED(size)); 562 563 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 564 early_pgtable_alloc, flags); 565 566 if (!(vm_flags & VM_NO_GUARD)) 567 size += PAGE_SIZE; 568 569 vma->addr = va_start; 570 vma->phys_addr = pa_start; 571 vma->size = size; 572 vma->flags = VM_MAP | vm_flags; 573 vma->caller = __builtin_return_address(0); 574 575 vm_area_add_early(vma); 576 } 577 578 static int __init parse_rodata(char *arg) 579 { 580 int ret = strtobool(arg, &rodata_enabled); 581 if (!ret) { 582 rodata_full = false; 583 return 0; 584 } 585 586 /* permit 'full' in addition to boolean options */ 587 if (strcmp(arg, "full")) 588 return -EINVAL; 589 590 rodata_enabled = true; 591 rodata_full = true; 592 return 0; 593 } 594 early_param("rodata", parse_rodata); 595 596 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 597 static int __init map_entry_trampoline(void) 598 { 599 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 600 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 601 602 /* The trampoline is always mapped and can therefore be global */ 603 pgprot_val(prot) &= ~PTE_NG; 604 605 /* Map only the text into the trampoline page table */ 606 memset(tramp_pg_dir, 0, PGD_SIZE); 607 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE, 608 prot, __pgd_pgtable_alloc, 0); 609 610 /* Map both the text and data into the kernel page table */ 611 __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot); 612 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 613 extern char __entry_tramp_data_start[]; 614 615 __set_fixmap(FIX_ENTRY_TRAMP_DATA, 616 __pa_symbol(__entry_tramp_data_start), 617 PAGE_KERNEL_RO); 618 } 619 620 return 0; 621 } 622 core_initcall(map_entry_trampoline); 623 #endif 624 625 /* 626 * Open coded check for BTI, only for use to determine configuration 627 * for early mappings for before the cpufeature code has run. 628 */ 629 static bool arm64_early_this_cpu_has_bti(void) 630 { 631 u64 pfr1; 632 633 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 634 return false; 635 636 pfr1 = read_sysreg_s(SYS_ID_AA64PFR1_EL1); 637 return cpuid_feature_extract_unsigned_field(pfr1, 638 ID_AA64PFR1_BT_SHIFT); 639 } 640 641 /* 642 * Create fine-grained mappings for the kernel. 643 */ 644 static void __init map_kernel(pgd_t *pgdp) 645 { 646 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 647 vmlinux_initdata, vmlinux_data; 648 649 /* 650 * External debuggers may need to write directly to the text 651 * mapping to install SW breakpoints. Allow this (only) when 652 * explicitly requested with rodata=off. 653 */ 654 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 655 656 /* 657 * If we have a CPU that supports BTI and a kernel built for 658 * BTI then mark the kernel executable text as guarded pages 659 * now so we don't have to rewrite the page tables later. 660 */ 661 if (arm64_early_this_cpu_has_bti()) 662 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 663 664 /* 665 * Only rodata will be remapped with different permissions later on, 666 * all other segments are allowed to use contiguous mappings. 667 */ 668 map_kernel_segment(pgdp, _text, _etext, text_prot, &vmlinux_text, 0, 669 VM_NO_GUARD); 670 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 671 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 672 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 673 &vmlinux_inittext, 0, VM_NO_GUARD); 674 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 675 &vmlinux_initdata, 0, VM_NO_GUARD); 676 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 677 678 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { 679 /* 680 * The fixmap falls in a separate pgd to the kernel, and doesn't 681 * live in the carveout for the swapper_pg_dir. We can simply 682 * re-use the existing dir for the fixmap. 683 */ 684 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), 685 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 686 } else if (CONFIG_PGTABLE_LEVELS > 3) { 687 pgd_t *bm_pgdp; 688 p4d_t *bm_p4dp; 689 pud_t *bm_pudp; 690 /* 691 * The fixmap shares its top level pgd entry with the kernel 692 * mapping. This can really only occur when we are running 693 * with 16k/4 levels, so we can simply reuse the pud level 694 * entry instead. 695 */ 696 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 697 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); 698 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); 699 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); 700 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 701 pud_clear_fixmap(); 702 } else { 703 BUG(); 704 } 705 706 kasan_copy_shadow(pgdp); 707 } 708 709 void __init paging_init(void) 710 { 711 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 712 713 map_kernel(pgdp); 714 map_mem(pgdp); 715 716 pgd_clear_fixmap(); 717 718 cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); 719 init_mm.pgd = swapper_pg_dir; 720 721 memblock_free(__pa_symbol(init_pg_dir), 722 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 723 724 memblock_allow_resize(); 725 } 726 727 /* 728 * Check whether a kernel address is valid (derived from arch/x86/). 729 */ 730 int kern_addr_valid(unsigned long addr) 731 { 732 pgd_t *pgdp; 733 p4d_t *p4dp; 734 pud_t *pudp, pud; 735 pmd_t *pmdp, pmd; 736 pte_t *ptep, pte; 737 738 addr = arch_kasan_reset_tag(addr); 739 if ((((long)addr) >> VA_BITS) != -1UL) 740 return 0; 741 742 pgdp = pgd_offset_k(addr); 743 if (pgd_none(READ_ONCE(*pgdp))) 744 return 0; 745 746 p4dp = p4d_offset(pgdp, addr); 747 if (p4d_none(READ_ONCE(*p4dp))) 748 return 0; 749 750 pudp = pud_offset(p4dp, addr); 751 pud = READ_ONCE(*pudp); 752 if (pud_none(pud)) 753 return 0; 754 755 if (pud_sect(pud)) 756 return pfn_valid(pud_pfn(pud)); 757 758 pmdp = pmd_offset(pudp, addr); 759 pmd = READ_ONCE(*pmdp); 760 if (pmd_none(pmd)) 761 return 0; 762 763 if (pmd_sect(pmd)) 764 return pfn_valid(pmd_pfn(pmd)); 765 766 ptep = pte_offset_kernel(pmdp, addr); 767 pte = READ_ONCE(*ptep); 768 if (pte_none(pte)) 769 return 0; 770 771 return pfn_valid(pte_pfn(pte)); 772 } 773 774 #ifdef CONFIG_MEMORY_HOTPLUG 775 static void free_hotplug_page_range(struct page *page, size_t size, 776 struct vmem_altmap *altmap) 777 { 778 if (altmap) { 779 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 780 } else { 781 WARN_ON(PageReserved(page)); 782 free_pages((unsigned long)page_address(page), get_order(size)); 783 } 784 } 785 786 static void free_hotplug_pgtable_page(struct page *page) 787 { 788 free_hotplug_page_range(page, PAGE_SIZE, NULL); 789 } 790 791 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 792 unsigned long floor, unsigned long ceiling, 793 unsigned long mask) 794 { 795 start &= mask; 796 if (start < floor) 797 return false; 798 799 if (ceiling) { 800 ceiling &= mask; 801 if (!ceiling) 802 return false; 803 } 804 805 if (end - 1 > ceiling - 1) 806 return false; 807 return true; 808 } 809 810 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 811 unsigned long end, bool free_mapped, 812 struct vmem_altmap *altmap) 813 { 814 pte_t *ptep, pte; 815 816 do { 817 ptep = pte_offset_kernel(pmdp, addr); 818 pte = READ_ONCE(*ptep); 819 if (pte_none(pte)) 820 continue; 821 822 WARN_ON(!pte_present(pte)); 823 pte_clear(&init_mm, addr, ptep); 824 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 825 if (free_mapped) 826 free_hotplug_page_range(pte_page(pte), 827 PAGE_SIZE, altmap); 828 } while (addr += PAGE_SIZE, addr < end); 829 } 830 831 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 832 unsigned long end, bool free_mapped, 833 struct vmem_altmap *altmap) 834 { 835 unsigned long next; 836 pmd_t *pmdp, pmd; 837 838 do { 839 next = pmd_addr_end(addr, end); 840 pmdp = pmd_offset(pudp, addr); 841 pmd = READ_ONCE(*pmdp); 842 if (pmd_none(pmd)) 843 continue; 844 845 WARN_ON(!pmd_present(pmd)); 846 if (pmd_sect(pmd)) { 847 pmd_clear(pmdp); 848 849 /* 850 * One TLBI should be sufficient here as the PMD_SIZE 851 * range is mapped with a single block entry. 852 */ 853 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 854 if (free_mapped) 855 free_hotplug_page_range(pmd_page(pmd), 856 PMD_SIZE, altmap); 857 continue; 858 } 859 WARN_ON(!pmd_table(pmd)); 860 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 861 } while (addr = next, addr < end); 862 } 863 864 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 865 unsigned long end, bool free_mapped, 866 struct vmem_altmap *altmap) 867 { 868 unsigned long next; 869 pud_t *pudp, pud; 870 871 do { 872 next = pud_addr_end(addr, end); 873 pudp = pud_offset(p4dp, addr); 874 pud = READ_ONCE(*pudp); 875 if (pud_none(pud)) 876 continue; 877 878 WARN_ON(!pud_present(pud)); 879 if (pud_sect(pud)) { 880 pud_clear(pudp); 881 882 /* 883 * One TLBI should be sufficient here as the PUD_SIZE 884 * range is mapped with a single block entry. 885 */ 886 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 887 if (free_mapped) 888 free_hotplug_page_range(pud_page(pud), 889 PUD_SIZE, altmap); 890 continue; 891 } 892 WARN_ON(!pud_table(pud)); 893 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 894 } while (addr = next, addr < end); 895 } 896 897 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 898 unsigned long end, bool free_mapped, 899 struct vmem_altmap *altmap) 900 { 901 unsigned long next; 902 p4d_t *p4dp, p4d; 903 904 do { 905 next = p4d_addr_end(addr, end); 906 p4dp = p4d_offset(pgdp, addr); 907 p4d = READ_ONCE(*p4dp); 908 if (p4d_none(p4d)) 909 continue; 910 911 WARN_ON(!p4d_present(p4d)); 912 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 913 } while (addr = next, addr < end); 914 } 915 916 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 917 bool free_mapped, struct vmem_altmap *altmap) 918 { 919 unsigned long next; 920 pgd_t *pgdp, pgd; 921 922 /* 923 * altmap can only be used as vmemmap mapping backing memory. 924 * In case the backing memory itself is not being freed, then 925 * altmap is irrelevant. Warn about this inconsistency when 926 * encountered. 927 */ 928 WARN_ON(!free_mapped && altmap); 929 930 do { 931 next = pgd_addr_end(addr, end); 932 pgdp = pgd_offset_k(addr); 933 pgd = READ_ONCE(*pgdp); 934 if (pgd_none(pgd)) 935 continue; 936 937 WARN_ON(!pgd_present(pgd)); 938 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 939 } while (addr = next, addr < end); 940 } 941 942 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 943 unsigned long end, unsigned long floor, 944 unsigned long ceiling) 945 { 946 pte_t *ptep, pte; 947 unsigned long i, start = addr; 948 949 do { 950 ptep = pte_offset_kernel(pmdp, addr); 951 pte = READ_ONCE(*ptep); 952 953 /* 954 * This is just a sanity check here which verifies that 955 * pte clearing has been done by earlier unmap loops. 956 */ 957 WARN_ON(!pte_none(pte)); 958 } while (addr += PAGE_SIZE, addr < end); 959 960 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 961 return; 962 963 /* 964 * Check whether we can free the pte page if the rest of the 965 * entries are empty. Overlap with other regions have been 966 * handled by the floor/ceiling check. 967 */ 968 ptep = pte_offset_kernel(pmdp, 0UL); 969 for (i = 0; i < PTRS_PER_PTE; i++) { 970 if (!pte_none(READ_ONCE(ptep[i]))) 971 return; 972 } 973 974 pmd_clear(pmdp); 975 __flush_tlb_kernel_pgtable(start); 976 free_hotplug_pgtable_page(virt_to_page(ptep)); 977 } 978 979 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 980 unsigned long end, unsigned long floor, 981 unsigned long ceiling) 982 { 983 pmd_t *pmdp, pmd; 984 unsigned long i, next, start = addr; 985 986 do { 987 next = pmd_addr_end(addr, end); 988 pmdp = pmd_offset(pudp, addr); 989 pmd = READ_ONCE(*pmdp); 990 if (pmd_none(pmd)) 991 continue; 992 993 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 994 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 995 } while (addr = next, addr < end); 996 997 if (CONFIG_PGTABLE_LEVELS <= 2) 998 return; 999 1000 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1001 return; 1002 1003 /* 1004 * Check whether we can free the pmd page if the rest of the 1005 * entries are empty. Overlap with other regions have been 1006 * handled by the floor/ceiling check. 1007 */ 1008 pmdp = pmd_offset(pudp, 0UL); 1009 for (i = 0; i < PTRS_PER_PMD; i++) { 1010 if (!pmd_none(READ_ONCE(pmdp[i]))) 1011 return; 1012 } 1013 1014 pud_clear(pudp); 1015 __flush_tlb_kernel_pgtable(start); 1016 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1017 } 1018 1019 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1020 unsigned long end, unsigned long floor, 1021 unsigned long ceiling) 1022 { 1023 pud_t *pudp, pud; 1024 unsigned long i, next, start = addr; 1025 1026 do { 1027 next = pud_addr_end(addr, end); 1028 pudp = pud_offset(p4dp, addr); 1029 pud = READ_ONCE(*pudp); 1030 if (pud_none(pud)) 1031 continue; 1032 1033 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1034 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1035 } while (addr = next, addr < end); 1036 1037 if (CONFIG_PGTABLE_LEVELS <= 3) 1038 return; 1039 1040 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1041 return; 1042 1043 /* 1044 * Check whether we can free the pud page if the rest of the 1045 * entries are empty. Overlap with other regions have been 1046 * handled by the floor/ceiling check. 1047 */ 1048 pudp = pud_offset(p4dp, 0UL); 1049 for (i = 0; i < PTRS_PER_PUD; i++) { 1050 if (!pud_none(READ_ONCE(pudp[i]))) 1051 return; 1052 } 1053 1054 p4d_clear(p4dp); 1055 __flush_tlb_kernel_pgtable(start); 1056 free_hotplug_pgtable_page(virt_to_page(pudp)); 1057 } 1058 1059 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1060 unsigned long end, unsigned long floor, 1061 unsigned long ceiling) 1062 { 1063 unsigned long next; 1064 p4d_t *p4dp, p4d; 1065 1066 do { 1067 next = p4d_addr_end(addr, end); 1068 p4dp = p4d_offset(pgdp, addr); 1069 p4d = READ_ONCE(*p4dp); 1070 if (p4d_none(p4d)) 1071 continue; 1072 1073 WARN_ON(!p4d_present(p4d)); 1074 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1075 } while (addr = next, addr < end); 1076 } 1077 1078 static void free_empty_tables(unsigned long addr, unsigned long end, 1079 unsigned long floor, unsigned long ceiling) 1080 { 1081 unsigned long next; 1082 pgd_t *pgdp, pgd; 1083 1084 do { 1085 next = pgd_addr_end(addr, end); 1086 pgdp = pgd_offset_k(addr); 1087 pgd = READ_ONCE(*pgdp); 1088 if (pgd_none(pgd)) 1089 continue; 1090 1091 WARN_ON(!pgd_present(pgd)); 1092 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1093 } while (addr = next, addr < end); 1094 } 1095 #endif 1096 1097 #ifdef CONFIG_SPARSEMEM_VMEMMAP 1098 #if !ARM64_SWAPPER_USES_SECTION_MAPS 1099 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1100 struct vmem_altmap *altmap) 1101 { 1102 return vmemmap_populate_basepages(start, end, node, altmap); 1103 } 1104 #else /* !ARM64_SWAPPER_USES_SECTION_MAPS */ 1105 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1106 struct vmem_altmap *altmap) 1107 { 1108 unsigned long addr = start; 1109 unsigned long next; 1110 pgd_t *pgdp; 1111 p4d_t *p4dp; 1112 pud_t *pudp; 1113 pmd_t *pmdp; 1114 1115 do { 1116 next = pmd_addr_end(addr, end); 1117 1118 pgdp = vmemmap_pgd_populate(addr, node); 1119 if (!pgdp) 1120 return -ENOMEM; 1121 1122 p4dp = vmemmap_p4d_populate(pgdp, addr, node); 1123 if (!p4dp) 1124 return -ENOMEM; 1125 1126 pudp = vmemmap_pud_populate(p4dp, addr, node); 1127 if (!pudp) 1128 return -ENOMEM; 1129 1130 pmdp = pmd_offset(pudp, addr); 1131 if (pmd_none(READ_ONCE(*pmdp))) { 1132 void *p = NULL; 1133 1134 p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); 1135 if (!p) 1136 return -ENOMEM; 1137 1138 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1139 } else 1140 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1141 } while (addr = next, addr != end); 1142 1143 return 0; 1144 } 1145 #endif /* !ARM64_SWAPPER_USES_SECTION_MAPS */ 1146 void vmemmap_free(unsigned long start, unsigned long end, 1147 struct vmem_altmap *altmap) 1148 { 1149 #ifdef CONFIG_MEMORY_HOTPLUG 1150 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1151 1152 unmap_hotplug_range(start, end, true, altmap); 1153 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1154 #endif 1155 } 1156 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 1157 1158 static inline pud_t * fixmap_pud(unsigned long addr) 1159 { 1160 pgd_t *pgdp = pgd_offset_k(addr); 1161 p4d_t *p4dp = p4d_offset(pgdp, addr); 1162 p4d_t p4d = READ_ONCE(*p4dp); 1163 1164 BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); 1165 1166 return pud_offset_kimg(p4dp, addr); 1167 } 1168 1169 static inline pmd_t * fixmap_pmd(unsigned long addr) 1170 { 1171 pud_t *pudp = fixmap_pud(addr); 1172 pud_t pud = READ_ONCE(*pudp); 1173 1174 BUG_ON(pud_none(pud) || pud_bad(pud)); 1175 1176 return pmd_offset_kimg(pudp, addr); 1177 } 1178 1179 static inline pte_t * fixmap_pte(unsigned long addr) 1180 { 1181 return &bm_pte[pte_index(addr)]; 1182 } 1183 1184 /* 1185 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 1186 * directly on kernel symbols (bm_p*d). This function is called too early to use 1187 * lm_alias so __p*d_populate functions must be used to populate with the 1188 * physical address from __pa_symbol. 1189 */ 1190 void __init early_fixmap_init(void) 1191 { 1192 pgd_t *pgdp; 1193 p4d_t *p4dp, p4d; 1194 pud_t *pudp; 1195 pmd_t *pmdp; 1196 unsigned long addr = FIXADDR_START; 1197 1198 pgdp = pgd_offset_k(addr); 1199 p4dp = p4d_offset(pgdp, addr); 1200 p4d = READ_ONCE(*p4dp); 1201 if (CONFIG_PGTABLE_LEVELS > 3 && 1202 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { 1203 /* 1204 * We only end up here if the kernel mapping and the fixmap 1205 * share the top level pgd entry, which should only happen on 1206 * 16k/4 levels configurations. 1207 */ 1208 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 1209 pudp = pud_offset_kimg(p4dp, addr); 1210 } else { 1211 if (p4d_none(p4d)) 1212 __p4d_populate(p4dp, __pa_symbol(bm_pud), PUD_TYPE_TABLE); 1213 pudp = fixmap_pud(addr); 1214 } 1215 if (pud_none(READ_ONCE(*pudp))) 1216 __pud_populate(pudp, __pa_symbol(bm_pmd), PMD_TYPE_TABLE); 1217 pmdp = fixmap_pmd(addr); 1218 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 1219 1220 /* 1221 * The boot-ioremap range spans multiple pmds, for which 1222 * we are not prepared: 1223 */ 1224 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 1225 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 1226 1227 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 1228 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 1229 WARN_ON(1); 1230 pr_warn("pmdp %p != %p, %p\n", 1231 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 1232 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 1233 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 1234 fix_to_virt(FIX_BTMAP_BEGIN)); 1235 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 1236 fix_to_virt(FIX_BTMAP_END)); 1237 1238 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 1239 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 1240 } 1241 } 1242 1243 /* 1244 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 1245 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 1246 */ 1247 void __set_fixmap(enum fixed_addresses idx, 1248 phys_addr_t phys, pgprot_t flags) 1249 { 1250 unsigned long addr = __fix_to_virt(idx); 1251 pte_t *ptep; 1252 1253 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 1254 1255 ptep = fixmap_pte(addr); 1256 1257 if (pgprot_val(flags)) { 1258 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 1259 } else { 1260 pte_clear(&init_mm, addr, ptep); 1261 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 1262 } 1263 } 1264 1265 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 1266 { 1267 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 1268 int offset; 1269 void *dt_virt; 1270 1271 /* 1272 * Check whether the physical FDT address is set and meets the minimum 1273 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 1274 * at least 8 bytes so that we can always access the magic and size 1275 * fields of the FDT header after mapping the first chunk, double check 1276 * here if that is indeed the case. 1277 */ 1278 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 1279 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 1280 return NULL; 1281 1282 /* 1283 * Make sure that the FDT region can be mapped without the need to 1284 * allocate additional translation table pages, so that it is safe 1285 * to call create_mapping_noalloc() this early. 1286 * 1287 * On 64k pages, the FDT will be mapped using PTEs, so we need to 1288 * be in the same PMD as the rest of the fixmap. 1289 * On 4k pages, we'll use section mappings for the FDT so we only 1290 * have to be in the same PUD. 1291 */ 1292 BUILD_BUG_ON(dt_virt_base % SZ_2M); 1293 1294 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 1295 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 1296 1297 offset = dt_phys % SWAPPER_BLOCK_SIZE; 1298 dt_virt = (void *)dt_virt_base + offset; 1299 1300 /* map the first chunk so we can read the size from the header */ 1301 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 1302 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 1303 1304 if (fdt_magic(dt_virt) != FDT_MAGIC) 1305 return NULL; 1306 1307 *size = fdt_totalsize(dt_virt); 1308 if (*size > MAX_FDT_SIZE) 1309 return NULL; 1310 1311 if (offset + *size > SWAPPER_BLOCK_SIZE) 1312 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 1313 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 1314 1315 return dt_virt; 1316 } 1317 1318 int __init arch_ioremap_p4d_supported(void) 1319 { 1320 return 0; 1321 } 1322 1323 int __init arch_ioremap_pud_supported(void) 1324 { 1325 /* 1326 * Only 4k granule supports level 1 block mappings. 1327 * SW table walks can't handle removal of intermediate entries. 1328 */ 1329 return IS_ENABLED(CONFIG_ARM64_4K_PAGES) && 1330 !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); 1331 } 1332 1333 int __init arch_ioremap_pmd_supported(void) 1334 { 1335 /* See arch_ioremap_pud_supported() */ 1336 return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); 1337 } 1338 1339 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1340 { 1341 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1342 1343 /* Only allow permission changes for now */ 1344 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1345 pud_val(new_pud))) 1346 return 0; 1347 1348 VM_BUG_ON(phys & ~PUD_MASK); 1349 set_pud(pudp, new_pud); 1350 return 1; 1351 } 1352 1353 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1354 { 1355 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1356 1357 /* Only allow permission changes for now */ 1358 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1359 pmd_val(new_pmd))) 1360 return 0; 1361 1362 VM_BUG_ON(phys & ~PMD_MASK); 1363 set_pmd(pmdp, new_pmd); 1364 return 1; 1365 } 1366 1367 int pud_clear_huge(pud_t *pudp) 1368 { 1369 if (!pud_sect(READ_ONCE(*pudp))) 1370 return 0; 1371 pud_clear(pudp); 1372 return 1; 1373 } 1374 1375 int pmd_clear_huge(pmd_t *pmdp) 1376 { 1377 if (!pmd_sect(READ_ONCE(*pmdp))) 1378 return 0; 1379 pmd_clear(pmdp); 1380 return 1; 1381 } 1382 1383 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1384 { 1385 pte_t *table; 1386 pmd_t pmd; 1387 1388 pmd = READ_ONCE(*pmdp); 1389 1390 if (!pmd_table(pmd)) { 1391 VM_WARN_ON(1); 1392 return 1; 1393 } 1394 1395 table = pte_offset_kernel(pmdp, addr); 1396 pmd_clear(pmdp); 1397 __flush_tlb_kernel_pgtable(addr); 1398 pte_free_kernel(NULL, table); 1399 return 1; 1400 } 1401 1402 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1403 { 1404 pmd_t *table; 1405 pmd_t *pmdp; 1406 pud_t pud; 1407 unsigned long next, end; 1408 1409 pud = READ_ONCE(*pudp); 1410 1411 if (!pud_table(pud)) { 1412 VM_WARN_ON(1); 1413 return 1; 1414 } 1415 1416 table = pmd_offset(pudp, addr); 1417 pmdp = table; 1418 next = addr; 1419 end = addr + PUD_SIZE; 1420 do { 1421 pmd_free_pte_page(pmdp, next); 1422 } while (pmdp++, next += PMD_SIZE, next != end); 1423 1424 pud_clear(pudp); 1425 __flush_tlb_kernel_pgtable(addr); 1426 pmd_free(NULL, table); 1427 return 1; 1428 } 1429 1430 int p4d_free_pud_page(p4d_t *p4d, unsigned long addr) 1431 { 1432 return 0; /* Don't attempt a block mapping */ 1433 } 1434 1435 #ifdef CONFIG_MEMORY_HOTPLUG 1436 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1437 { 1438 unsigned long end = start + size; 1439 1440 WARN_ON(pgdir != init_mm.pgd); 1441 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1442 1443 unmap_hotplug_range(start, end, false, NULL); 1444 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1445 } 1446 1447 int arch_add_memory(int nid, u64 start, u64 size, 1448 struct mhp_params *params) 1449 { 1450 int ret, flags = 0; 1451 1452 if (rodata_full || debug_pagealloc_enabled()) 1453 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1454 1455 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1456 size, params->pgprot, __pgd_pgtable_alloc, 1457 flags); 1458 1459 memblock_clear_nomap(start, size); 1460 1461 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1462 params); 1463 if (ret) 1464 __remove_pgd_mapping(swapper_pg_dir, 1465 __phys_to_virt(start), size); 1466 return ret; 1467 } 1468 1469 void arch_remove_memory(int nid, u64 start, u64 size, 1470 struct vmem_altmap *altmap) 1471 { 1472 unsigned long start_pfn = start >> PAGE_SHIFT; 1473 unsigned long nr_pages = size >> PAGE_SHIFT; 1474 1475 __remove_pages(start_pfn, nr_pages, altmap); 1476 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1477 } 1478 1479 /* 1480 * This memory hotplug notifier helps prevent boot memory from being 1481 * inadvertently removed as it blocks pfn range offlining process in 1482 * __offline_pages(). Hence this prevents both offlining as well as 1483 * removal process for boot memory which is initially always online. 1484 * In future if and when boot memory could be removed, this notifier 1485 * should be dropped and free_hotplug_page_range() should handle any 1486 * reserved pages allocated during boot. 1487 */ 1488 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1489 unsigned long action, void *data) 1490 { 1491 struct mem_section *ms; 1492 struct memory_notify *arg = data; 1493 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1494 unsigned long pfn = arg->start_pfn; 1495 1496 if (action != MEM_GOING_OFFLINE) 1497 return NOTIFY_OK; 1498 1499 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1500 ms = __pfn_to_section(pfn); 1501 if (early_section(ms)) 1502 return NOTIFY_BAD; 1503 } 1504 return NOTIFY_OK; 1505 } 1506 1507 static struct notifier_block prevent_bootmem_remove_nb = { 1508 .notifier_call = prevent_bootmem_remove_notifier, 1509 }; 1510 1511 static int __init prevent_bootmem_remove_init(void) 1512 { 1513 return register_memory_notifier(&prevent_bootmem_remove_nb); 1514 } 1515 device_initcall(prevent_bootmem_remove_init); 1516 #endif 1517