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/fs.h> 21 #include <linux/io.h> 22 #include <linux/mm.h> 23 #include <linux/vmalloc.h> 24 25 #include <asm/barrier.h> 26 #include <asm/cputype.h> 27 #include <asm/fixmap.h> 28 #include <asm/kasan.h> 29 #include <asm/kernel-pgtable.h> 30 #include <asm/sections.h> 31 #include <asm/setup.h> 32 #include <linux/sizes.h> 33 #include <asm/tlb.h> 34 #include <asm/mmu_context.h> 35 #include <asm/ptdump.h> 36 #include <asm/tlbflush.h> 37 38 #define NO_BLOCK_MAPPINGS BIT(0) 39 #define NO_CONT_MAPPINGS BIT(1) 40 41 u64 idmap_t0sz = TCR_T0SZ(VA_BITS); 42 u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; 43 44 u64 __section(".mmuoff.data.write") vabits_actual; 45 EXPORT_SYMBOL(vabits_actual); 46 47 u64 kimage_voffset __ro_after_init; 48 EXPORT_SYMBOL(kimage_voffset); 49 50 /* 51 * Empty_zero_page is a special page that is used for zero-initialized data 52 * and COW. 53 */ 54 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 55 EXPORT_SYMBOL(empty_zero_page); 56 57 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; 58 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; 59 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; 60 61 static DEFINE_SPINLOCK(swapper_pgdir_lock); 62 63 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 64 { 65 pgd_t *fixmap_pgdp; 66 67 spin_lock(&swapper_pgdir_lock); 68 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 69 WRITE_ONCE(*fixmap_pgdp, pgd); 70 /* 71 * We need dsb(ishst) here to ensure the page-table-walker sees 72 * our new entry before set_p?d() returns. The fixmap's 73 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 74 */ 75 pgd_clear_fixmap(); 76 spin_unlock(&swapper_pgdir_lock); 77 } 78 79 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 80 unsigned long size, pgprot_t vma_prot) 81 { 82 if (!pfn_valid(pfn)) 83 return pgprot_noncached(vma_prot); 84 else if (file->f_flags & O_SYNC) 85 return pgprot_writecombine(vma_prot); 86 return vma_prot; 87 } 88 EXPORT_SYMBOL(phys_mem_access_prot); 89 90 static phys_addr_t __init early_pgtable_alloc(int shift) 91 { 92 phys_addr_t phys; 93 void *ptr; 94 95 phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); 96 if (!phys) 97 panic("Failed to allocate page table page\n"); 98 99 /* 100 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE 101 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise 102 * any level of table. 103 */ 104 ptr = pte_set_fixmap(phys); 105 106 memset(ptr, 0, PAGE_SIZE); 107 108 /* 109 * Implicit barriers also ensure the zeroed page is visible to the page 110 * table walker 111 */ 112 pte_clear_fixmap(); 113 114 return phys; 115 } 116 117 static bool pgattr_change_is_safe(u64 old, u64 new) 118 { 119 /* 120 * The following mapping attributes may be updated in live 121 * kernel mappings without the need for break-before-make. 122 */ 123 static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 124 125 /* creating or taking down mappings is always safe */ 126 if (old == 0 || new == 0) 127 return true; 128 129 /* live contiguous mappings may not be manipulated at all */ 130 if ((old | new) & PTE_CONT) 131 return false; 132 133 /* Transitioning from Non-Global to Global is unsafe */ 134 if (old & ~new & PTE_NG) 135 return false; 136 137 return ((old ^ new) & ~mask) == 0; 138 } 139 140 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 141 phys_addr_t phys, pgprot_t prot) 142 { 143 pte_t *ptep; 144 145 ptep = pte_set_fixmap_offset(pmdp, addr); 146 do { 147 pte_t old_pte = READ_ONCE(*ptep); 148 149 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 150 151 /* 152 * After the PTE entry has been populated once, we 153 * only allow updates to the permission attributes. 154 */ 155 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 156 READ_ONCE(pte_val(*ptep)))); 157 158 phys += PAGE_SIZE; 159 } while (ptep++, addr += PAGE_SIZE, addr != end); 160 161 pte_clear_fixmap(); 162 } 163 164 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 165 unsigned long end, phys_addr_t phys, 166 pgprot_t prot, 167 phys_addr_t (*pgtable_alloc)(int), 168 int flags) 169 { 170 unsigned long next; 171 pmd_t pmd = READ_ONCE(*pmdp); 172 173 BUG_ON(pmd_sect(pmd)); 174 if (pmd_none(pmd)) { 175 phys_addr_t pte_phys; 176 BUG_ON(!pgtable_alloc); 177 pte_phys = pgtable_alloc(PAGE_SHIFT); 178 __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE); 179 pmd = READ_ONCE(*pmdp); 180 } 181 BUG_ON(pmd_bad(pmd)); 182 183 do { 184 pgprot_t __prot = prot; 185 186 next = pte_cont_addr_end(addr, end); 187 188 /* use a contiguous mapping if the range is suitably aligned */ 189 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 190 (flags & NO_CONT_MAPPINGS) == 0) 191 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 192 193 init_pte(pmdp, addr, next, phys, __prot); 194 195 phys += next - addr; 196 } while (addr = next, addr != end); 197 } 198 199 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 200 phys_addr_t phys, pgprot_t prot, 201 phys_addr_t (*pgtable_alloc)(int), int flags) 202 { 203 unsigned long next; 204 pmd_t *pmdp; 205 206 pmdp = pmd_set_fixmap_offset(pudp, addr); 207 do { 208 pmd_t old_pmd = READ_ONCE(*pmdp); 209 210 next = pmd_addr_end(addr, end); 211 212 /* try section mapping first */ 213 if (((addr | next | phys) & ~SECTION_MASK) == 0 && 214 (flags & NO_BLOCK_MAPPINGS) == 0) { 215 pmd_set_huge(pmdp, phys, prot); 216 217 /* 218 * After the PMD entry has been populated once, we 219 * only allow updates to the permission attributes. 220 */ 221 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 222 READ_ONCE(pmd_val(*pmdp)))); 223 } else { 224 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 225 pgtable_alloc, flags); 226 227 BUG_ON(pmd_val(old_pmd) != 0 && 228 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 229 } 230 phys += next - addr; 231 } while (pmdp++, addr = next, addr != end); 232 233 pmd_clear_fixmap(); 234 } 235 236 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 237 unsigned long end, phys_addr_t phys, 238 pgprot_t prot, 239 phys_addr_t (*pgtable_alloc)(int), int flags) 240 { 241 unsigned long next; 242 pud_t pud = READ_ONCE(*pudp); 243 244 /* 245 * Check for initial section mappings in the pgd/pud. 246 */ 247 BUG_ON(pud_sect(pud)); 248 if (pud_none(pud)) { 249 phys_addr_t pmd_phys; 250 BUG_ON(!pgtable_alloc); 251 pmd_phys = pgtable_alloc(PMD_SHIFT); 252 __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE); 253 pud = READ_ONCE(*pudp); 254 } 255 BUG_ON(pud_bad(pud)); 256 257 do { 258 pgprot_t __prot = prot; 259 260 next = pmd_cont_addr_end(addr, end); 261 262 /* use a contiguous mapping if the range is suitably aligned */ 263 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 264 (flags & NO_CONT_MAPPINGS) == 0) 265 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 266 267 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 268 269 phys += next - addr; 270 } while (addr = next, addr != end); 271 } 272 273 static inline bool use_1G_block(unsigned long addr, unsigned long next, 274 unsigned long phys) 275 { 276 if (PAGE_SHIFT != 12) 277 return false; 278 279 if (((addr | next | phys) & ~PUD_MASK) != 0) 280 return false; 281 282 return true; 283 } 284 285 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 286 phys_addr_t phys, pgprot_t prot, 287 phys_addr_t (*pgtable_alloc)(int), 288 int flags) 289 { 290 unsigned long next; 291 pud_t *pudp; 292 pgd_t pgd = READ_ONCE(*pgdp); 293 294 if (pgd_none(pgd)) { 295 phys_addr_t pud_phys; 296 BUG_ON(!pgtable_alloc); 297 pud_phys = pgtable_alloc(PUD_SHIFT); 298 __pgd_populate(pgdp, pud_phys, PUD_TYPE_TABLE); 299 pgd = READ_ONCE(*pgdp); 300 } 301 BUG_ON(pgd_bad(pgd)); 302 303 pudp = pud_set_fixmap_offset(pgdp, addr); 304 do { 305 pud_t old_pud = READ_ONCE(*pudp); 306 307 next = pud_addr_end(addr, end); 308 309 /* 310 * For 4K granule only, attempt to put down a 1GB block 311 */ 312 if (use_1G_block(addr, next, phys) && 313 (flags & NO_BLOCK_MAPPINGS) == 0) { 314 pud_set_huge(pudp, phys, prot); 315 316 /* 317 * After the PUD entry has been populated once, we 318 * only allow updates to the permission attributes. 319 */ 320 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 321 READ_ONCE(pud_val(*pudp)))); 322 } else { 323 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 324 pgtable_alloc, flags); 325 326 BUG_ON(pud_val(old_pud) != 0 && 327 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 328 } 329 phys += next - addr; 330 } while (pudp++, addr = next, addr != end); 331 332 pud_clear_fixmap(); 333 } 334 335 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 336 unsigned long virt, phys_addr_t size, 337 pgprot_t prot, 338 phys_addr_t (*pgtable_alloc)(int), 339 int flags) 340 { 341 unsigned long addr, end, next; 342 pgd_t *pgdp = pgd_offset_raw(pgdir, virt); 343 344 /* 345 * If the virtual and physical address don't have the same offset 346 * within a page, we cannot map the region as the caller expects. 347 */ 348 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 349 return; 350 351 phys &= PAGE_MASK; 352 addr = virt & PAGE_MASK; 353 end = PAGE_ALIGN(virt + size); 354 355 do { 356 next = pgd_addr_end(addr, end); 357 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 358 flags); 359 phys += next - addr; 360 } while (pgdp++, addr = next, addr != end); 361 } 362 363 static phys_addr_t __pgd_pgtable_alloc(int shift) 364 { 365 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 366 BUG_ON(!ptr); 367 368 /* Ensure the zeroed page is visible to the page table walker */ 369 dsb(ishst); 370 return __pa(ptr); 371 } 372 373 static phys_addr_t pgd_pgtable_alloc(int shift) 374 { 375 phys_addr_t pa = __pgd_pgtable_alloc(shift); 376 377 /* 378 * Call proper page table ctor in case later we need to 379 * call core mm functions like apply_to_page_range() on 380 * this pre-allocated page table. 381 * 382 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 383 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 384 */ 385 if (shift == PAGE_SHIFT) 386 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 387 else if (shift == PMD_SHIFT) 388 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 389 390 return pa; 391 } 392 393 /* 394 * This function can only be used to modify existing table entries, 395 * without allocating new levels of table. Note that this permits the 396 * creation of new section or page entries. 397 */ 398 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 399 phys_addr_t size, pgprot_t prot) 400 { 401 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 402 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 403 &phys, virt); 404 return; 405 } 406 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 407 NO_CONT_MAPPINGS); 408 } 409 410 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 411 unsigned long virt, phys_addr_t size, 412 pgprot_t prot, bool page_mappings_only) 413 { 414 int flags = 0; 415 416 BUG_ON(mm == &init_mm); 417 418 if (page_mappings_only) 419 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 420 421 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 422 pgd_pgtable_alloc, flags); 423 } 424 425 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 426 phys_addr_t size, pgprot_t prot) 427 { 428 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 429 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 430 &phys, virt); 431 return; 432 } 433 434 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 435 NO_CONT_MAPPINGS); 436 437 /* flush the TLBs after updating live kernel mappings */ 438 flush_tlb_kernel_range(virt, virt + size); 439 } 440 441 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 442 phys_addr_t end, pgprot_t prot, int flags) 443 { 444 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 445 prot, early_pgtable_alloc, flags); 446 } 447 448 void __init mark_linear_text_alias_ro(void) 449 { 450 /* 451 * Remove the write permissions from the linear alias of .text/.rodata 452 */ 453 update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text), 454 (unsigned long)__init_begin - (unsigned long)_text, 455 PAGE_KERNEL_RO); 456 } 457 458 static void __init map_mem(pgd_t *pgdp) 459 { 460 phys_addr_t kernel_start = __pa_symbol(_text); 461 phys_addr_t kernel_end = __pa_symbol(__init_begin); 462 struct memblock_region *reg; 463 int flags = 0; 464 465 if (rodata_full || debug_pagealloc_enabled()) 466 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 467 468 /* 469 * Take care not to create a writable alias for the 470 * read-only text and rodata sections of the kernel image. 471 * So temporarily mark them as NOMAP to skip mappings in 472 * the following for-loop 473 */ 474 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 475 #ifdef CONFIG_KEXEC_CORE 476 if (crashk_res.end) 477 memblock_mark_nomap(crashk_res.start, 478 resource_size(&crashk_res)); 479 #endif 480 481 /* map all the memory banks */ 482 for_each_memblock(memory, reg) { 483 phys_addr_t start = reg->base; 484 phys_addr_t end = start + reg->size; 485 486 if (start >= end) 487 break; 488 if (memblock_is_nomap(reg)) 489 continue; 490 491 __map_memblock(pgdp, start, end, PAGE_KERNEL, flags); 492 } 493 494 /* 495 * Map the linear alias of the [_text, __init_begin) interval 496 * as non-executable now, and remove the write permission in 497 * mark_linear_text_alias_ro() below (which will be called after 498 * alternative patching has completed). This makes the contents 499 * of the region accessible to subsystems such as hibernate, 500 * but protects it from inadvertent modification or execution. 501 * Note that contiguous mappings cannot be remapped in this way, 502 * so we should avoid them here. 503 */ 504 __map_memblock(pgdp, kernel_start, kernel_end, 505 PAGE_KERNEL, NO_CONT_MAPPINGS); 506 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 507 508 #ifdef CONFIG_KEXEC_CORE 509 /* 510 * Use page-level mappings here so that we can shrink the region 511 * in page granularity and put back unused memory to buddy system 512 * through /sys/kernel/kexec_crash_size interface. 513 */ 514 if (crashk_res.end) { 515 __map_memblock(pgdp, crashk_res.start, crashk_res.end + 1, 516 PAGE_KERNEL, 517 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 518 memblock_clear_nomap(crashk_res.start, 519 resource_size(&crashk_res)); 520 } 521 #endif 522 } 523 524 void mark_rodata_ro(void) 525 { 526 unsigned long section_size; 527 528 /* 529 * mark .rodata as read only. Use __init_begin rather than __end_rodata 530 * to cover NOTES and EXCEPTION_TABLE. 531 */ 532 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 533 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 534 section_size, PAGE_KERNEL_RO); 535 536 debug_checkwx(); 537 } 538 539 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 540 pgprot_t prot, struct vm_struct *vma, 541 int flags, unsigned long vm_flags) 542 { 543 phys_addr_t pa_start = __pa_symbol(va_start); 544 unsigned long size = va_end - va_start; 545 546 BUG_ON(!PAGE_ALIGNED(pa_start)); 547 BUG_ON(!PAGE_ALIGNED(size)); 548 549 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 550 early_pgtable_alloc, flags); 551 552 if (!(vm_flags & VM_NO_GUARD)) 553 size += PAGE_SIZE; 554 555 vma->addr = va_start; 556 vma->phys_addr = pa_start; 557 vma->size = size; 558 vma->flags = VM_MAP | vm_flags; 559 vma->caller = __builtin_return_address(0); 560 561 vm_area_add_early(vma); 562 } 563 564 static int __init parse_rodata(char *arg) 565 { 566 int ret = strtobool(arg, &rodata_enabled); 567 if (!ret) { 568 rodata_full = false; 569 return 0; 570 } 571 572 /* permit 'full' in addition to boolean options */ 573 if (strcmp(arg, "full")) 574 return -EINVAL; 575 576 rodata_enabled = true; 577 rodata_full = true; 578 return 0; 579 } 580 early_param("rodata", parse_rodata); 581 582 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 583 static int __init map_entry_trampoline(void) 584 { 585 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 586 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 587 588 /* The trampoline is always mapped and can therefore be global */ 589 pgprot_val(prot) &= ~PTE_NG; 590 591 /* Map only the text into the trampoline page table */ 592 memset(tramp_pg_dir, 0, PGD_SIZE); 593 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE, 594 prot, __pgd_pgtable_alloc, 0); 595 596 /* Map both the text and data into the kernel page table */ 597 __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot); 598 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 599 extern char __entry_tramp_data_start[]; 600 601 __set_fixmap(FIX_ENTRY_TRAMP_DATA, 602 __pa_symbol(__entry_tramp_data_start), 603 PAGE_KERNEL_RO); 604 } 605 606 return 0; 607 } 608 core_initcall(map_entry_trampoline); 609 #endif 610 611 /* 612 * Create fine-grained mappings for the kernel. 613 */ 614 static void __init map_kernel(pgd_t *pgdp) 615 { 616 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 617 vmlinux_initdata, vmlinux_data; 618 619 /* 620 * External debuggers may need to write directly to the text 621 * mapping to install SW breakpoints. Allow this (only) when 622 * explicitly requested with rodata=off. 623 */ 624 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 625 626 /* 627 * Only rodata will be remapped with different permissions later on, 628 * all other segments are allowed to use contiguous mappings. 629 */ 630 map_kernel_segment(pgdp, _text, _etext, text_prot, &vmlinux_text, 0, 631 VM_NO_GUARD); 632 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 633 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 634 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 635 &vmlinux_inittext, 0, VM_NO_GUARD); 636 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 637 &vmlinux_initdata, 0, VM_NO_GUARD); 638 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 639 640 if (!READ_ONCE(pgd_val(*pgd_offset_raw(pgdp, FIXADDR_START)))) { 641 /* 642 * The fixmap falls in a separate pgd to the kernel, and doesn't 643 * live in the carveout for the swapper_pg_dir. We can simply 644 * re-use the existing dir for the fixmap. 645 */ 646 set_pgd(pgd_offset_raw(pgdp, FIXADDR_START), 647 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 648 } else if (CONFIG_PGTABLE_LEVELS > 3) { 649 pgd_t *bm_pgdp; 650 pud_t *bm_pudp; 651 /* 652 * The fixmap shares its top level pgd entry with the kernel 653 * mapping. This can really only occur when we are running 654 * with 16k/4 levels, so we can simply reuse the pud level 655 * entry instead. 656 */ 657 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 658 bm_pgdp = pgd_offset_raw(pgdp, FIXADDR_START); 659 bm_pudp = pud_set_fixmap_offset(bm_pgdp, FIXADDR_START); 660 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 661 pud_clear_fixmap(); 662 } else { 663 BUG(); 664 } 665 666 kasan_copy_shadow(pgdp); 667 } 668 669 void __init paging_init(void) 670 { 671 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 672 673 map_kernel(pgdp); 674 map_mem(pgdp); 675 676 pgd_clear_fixmap(); 677 678 cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); 679 init_mm.pgd = swapper_pg_dir; 680 681 memblock_free(__pa_symbol(init_pg_dir), 682 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 683 684 memblock_allow_resize(); 685 } 686 687 /* 688 * Check whether a kernel address is valid (derived from arch/x86/). 689 */ 690 int kern_addr_valid(unsigned long addr) 691 { 692 pgd_t *pgdp; 693 pud_t *pudp, pud; 694 pmd_t *pmdp, pmd; 695 pte_t *ptep, pte; 696 697 if ((((long)addr) >> VA_BITS) != -1UL) 698 return 0; 699 700 pgdp = pgd_offset_k(addr); 701 if (pgd_none(READ_ONCE(*pgdp))) 702 return 0; 703 704 pudp = pud_offset(pgdp, addr); 705 pud = READ_ONCE(*pudp); 706 if (pud_none(pud)) 707 return 0; 708 709 if (pud_sect(pud)) 710 return pfn_valid(pud_pfn(pud)); 711 712 pmdp = pmd_offset(pudp, addr); 713 pmd = READ_ONCE(*pmdp); 714 if (pmd_none(pmd)) 715 return 0; 716 717 if (pmd_sect(pmd)) 718 return pfn_valid(pmd_pfn(pmd)); 719 720 ptep = pte_offset_kernel(pmdp, addr); 721 pte = READ_ONCE(*ptep); 722 if (pte_none(pte)) 723 return 0; 724 725 return pfn_valid(pte_pfn(pte)); 726 } 727 #ifdef CONFIG_SPARSEMEM_VMEMMAP 728 #if !ARM64_SWAPPER_USES_SECTION_MAPS 729 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 730 struct vmem_altmap *altmap) 731 { 732 return vmemmap_populate_basepages(start, end, node); 733 } 734 #else /* !ARM64_SWAPPER_USES_SECTION_MAPS */ 735 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 736 struct vmem_altmap *altmap) 737 { 738 unsigned long addr = start; 739 unsigned long next; 740 pgd_t *pgdp; 741 pud_t *pudp; 742 pmd_t *pmdp; 743 744 do { 745 next = pmd_addr_end(addr, end); 746 747 pgdp = vmemmap_pgd_populate(addr, node); 748 if (!pgdp) 749 return -ENOMEM; 750 751 pudp = vmemmap_pud_populate(pgdp, addr, node); 752 if (!pudp) 753 return -ENOMEM; 754 755 pmdp = pmd_offset(pudp, addr); 756 if (pmd_none(READ_ONCE(*pmdp))) { 757 void *p = NULL; 758 759 p = vmemmap_alloc_block_buf(PMD_SIZE, node); 760 if (!p) 761 return -ENOMEM; 762 763 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 764 } else 765 vmemmap_verify((pte_t *)pmdp, node, addr, next); 766 } while (addr = next, addr != end); 767 768 return 0; 769 } 770 #endif /* !ARM64_SWAPPER_USES_SECTION_MAPS */ 771 void vmemmap_free(unsigned long start, unsigned long end, 772 struct vmem_altmap *altmap) 773 { 774 } 775 #endif /* CONFIG_SPARSEMEM_VMEMMAP */ 776 777 static inline pud_t * fixmap_pud(unsigned long addr) 778 { 779 pgd_t *pgdp = pgd_offset_k(addr); 780 pgd_t pgd = READ_ONCE(*pgdp); 781 782 BUG_ON(pgd_none(pgd) || pgd_bad(pgd)); 783 784 return pud_offset_kimg(pgdp, addr); 785 } 786 787 static inline pmd_t * fixmap_pmd(unsigned long addr) 788 { 789 pud_t *pudp = fixmap_pud(addr); 790 pud_t pud = READ_ONCE(*pudp); 791 792 BUG_ON(pud_none(pud) || pud_bad(pud)); 793 794 return pmd_offset_kimg(pudp, addr); 795 } 796 797 static inline pte_t * fixmap_pte(unsigned long addr) 798 { 799 return &bm_pte[pte_index(addr)]; 800 } 801 802 /* 803 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 804 * directly on kernel symbols (bm_p*d). This function is called too early to use 805 * lm_alias so __p*d_populate functions must be used to populate with the 806 * physical address from __pa_symbol. 807 */ 808 void __init early_fixmap_init(void) 809 { 810 pgd_t *pgdp, pgd; 811 pud_t *pudp; 812 pmd_t *pmdp; 813 unsigned long addr = FIXADDR_START; 814 815 pgdp = pgd_offset_k(addr); 816 pgd = READ_ONCE(*pgdp); 817 if (CONFIG_PGTABLE_LEVELS > 3 && 818 !(pgd_none(pgd) || pgd_page_paddr(pgd) == __pa_symbol(bm_pud))) { 819 /* 820 * We only end up here if the kernel mapping and the fixmap 821 * share the top level pgd entry, which should only happen on 822 * 16k/4 levels configurations. 823 */ 824 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 825 pudp = pud_offset_kimg(pgdp, addr); 826 } else { 827 if (pgd_none(pgd)) 828 __pgd_populate(pgdp, __pa_symbol(bm_pud), PUD_TYPE_TABLE); 829 pudp = fixmap_pud(addr); 830 } 831 if (pud_none(READ_ONCE(*pudp))) 832 __pud_populate(pudp, __pa_symbol(bm_pmd), PMD_TYPE_TABLE); 833 pmdp = fixmap_pmd(addr); 834 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 835 836 /* 837 * The boot-ioremap range spans multiple pmds, for which 838 * we are not prepared: 839 */ 840 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 841 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 842 843 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 844 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 845 WARN_ON(1); 846 pr_warn("pmdp %p != %p, %p\n", 847 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 848 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 849 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 850 fix_to_virt(FIX_BTMAP_BEGIN)); 851 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 852 fix_to_virt(FIX_BTMAP_END)); 853 854 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 855 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 856 } 857 } 858 859 /* 860 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 861 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 862 */ 863 void __set_fixmap(enum fixed_addresses idx, 864 phys_addr_t phys, pgprot_t flags) 865 { 866 unsigned long addr = __fix_to_virt(idx); 867 pte_t *ptep; 868 869 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 870 871 ptep = fixmap_pte(addr); 872 873 if (pgprot_val(flags)) { 874 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 875 } else { 876 pte_clear(&init_mm, addr, ptep); 877 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 878 } 879 } 880 881 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 882 { 883 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 884 int offset; 885 void *dt_virt; 886 887 /* 888 * Check whether the physical FDT address is set and meets the minimum 889 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 890 * at least 8 bytes so that we can always access the magic and size 891 * fields of the FDT header after mapping the first chunk, double check 892 * here if that is indeed the case. 893 */ 894 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 895 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 896 return NULL; 897 898 /* 899 * Make sure that the FDT region can be mapped without the need to 900 * allocate additional translation table pages, so that it is safe 901 * to call create_mapping_noalloc() this early. 902 * 903 * On 64k pages, the FDT will be mapped using PTEs, so we need to 904 * be in the same PMD as the rest of the fixmap. 905 * On 4k pages, we'll use section mappings for the FDT so we only 906 * have to be in the same PUD. 907 */ 908 BUILD_BUG_ON(dt_virt_base % SZ_2M); 909 910 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 911 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 912 913 offset = dt_phys % SWAPPER_BLOCK_SIZE; 914 dt_virt = (void *)dt_virt_base + offset; 915 916 /* map the first chunk so we can read the size from the header */ 917 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 918 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 919 920 if (fdt_magic(dt_virt) != FDT_MAGIC) 921 return NULL; 922 923 *size = fdt_totalsize(dt_virt); 924 if (*size > MAX_FDT_SIZE) 925 return NULL; 926 927 if (offset + *size > SWAPPER_BLOCK_SIZE) 928 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 929 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 930 931 return dt_virt; 932 } 933 934 int __init arch_ioremap_p4d_supported(void) 935 { 936 return 0; 937 } 938 939 int __init arch_ioremap_pud_supported(void) 940 { 941 /* 942 * Only 4k granule supports level 1 block mappings. 943 * SW table walks can't handle removal of intermediate entries. 944 */ 945 return IS_ENABLED(CONFIG_ARM64_4K_PAGES) && 946 !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); 947 } 948 949 int __init arch_ioremap_pmd_supported(void) 950 { 951 /* See arch_ioremap_pud_supported() */ 952 return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); 953 } 954 955 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 956 { 957 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 958 959 /* Only allow permission changes for now */ 960 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 961 pud_val(new_pud))) 962 return 0; 963 964 VM_BUG_ON(phys & ~PUD_MASK); 965 set_pud(pudp, new_pud); 966 return 1; 967 } 968 969 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 970 { 971 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 972 973 /* Only allow permission changes for now */ 974 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 975 pmd_val(new_pmd))) 976 return 0; 977 978 VM_BUG_ON(phys & ~PMD_MASK); 979 set_pmd(pmdp, new_pmd); 980 return 1; 981 } 982 983 int pud_clear_huge(pud_t *pudp) 984 { 985 if (!pud_sect(READ_ONCE(*pudp))) 986 return 0; 987 pud_clear(pudp); 988 return 1; 989 } 990 991 int pmd_clear_huge(pmd_t *pmdp) 992 { 993 if (!pmd_sect(READ_ONCE(*pmdp))) 994 return 0; 995 pmd_clear(pmdp); 996 return 1; 997 } 998 999 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1000 { 1001 pte_t *table; 1002 pmd_t pmd; 1003 1004 pmd = READ_ONCE(*pmdp); 1005 1006 if (!pmd_table(pmd)) { 1007 VM_WARN_ON(1); 1008 return 1; 1009 } 1010 1011 table = pte_offset_kernel(pmdp, addr); 1012 pmd_clear(pmdp); 1013 __flush_tlb_kernel_pgtable(addr); 1014 pte_free_kernel(NULL, table); 1015 return 1; 1016 } 1017 1018 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1019 { 1020 pmd_t *table; 1021 pmd_t *pmdp; 1022 pud_t pud; 1023 unsigned long next, end; 1024 1025 pud = READ_ONCE(*pudp); 1026 1027 if (!pud_table(pud)) { 1028 VM_WARN_ON(1); 1029 return 1; 1030 } 1031 1032 table = pmd_offset(pudp, addr); 1033 pmdp = table; 1034 next = addr; 1035 end = addr + PUD_SIZE; 1036 do { 1037 pmd_free_pte_page(pmdp, next); 1038 } while (pmdp++, next += PMD_SIZE, next != end); 1039 1040 pud_clear(pudp); 1041 __flush_tlb_kernel_pgtable(addr); 1042 pmd_free(NULL, table); 1043 return 1; 1044 } 1045 1046 int p4d_free_pud_page(p4d_t *p4d, unsigned long addr) 1047 { 1048 return 0; /* Don't attempt a block mapping */ 1049 } 1050 1051 #ifdef CONFIG_MEMORY_HOTPLUG 1052 int arch_add_memory(int nid, u64 start, u64 size, 1053 struct mhp_restrictions *restrictions) 1054 { 1055 int flags = 0; 1056 1057 if (rodata_full || debug_pagealloc_enabled()) 1058 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1059 1060 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1061 size, PAGE_KERNEL, __pgd_pgtable_alloc, flags); 1062 1063 memblock_clear_nomap(start, size); 1064 1065 return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1066 restrictions); 1067 } 1068 void arch_remove_memory(int nid, u64 start, u64 size, 1069 struct vmem_altmap *altmap) 1070 { 1071 unsigned long start_pfn = start >> PAGE_SHIFT; 1072 unsigned long nr_pages = size >> PAGE_SHIFT; 1073 1074 /* 1075 * FIXME: Cleanup page tables (also in arch_add_memory() in case 1076 * adding fails). Until then, this function should only be used 1077 * during memory hotplug (adding memory), not for memory 1078 * unplug. ARCH_ENABLE_MEMORY_HOTREMOVE must not be 1079 * unlocked yet. 1080 */ 1081 __remove_pages(start_pfn, nr_pages, altmap); 1082 } 1083 #endif 1084