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 43u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN); 44u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; 45 46u64 __section(".mmuoff.data.write") vabits_actual; 47EXPORT_SYMBOL(vabits_actual); 48 49u64 kimage_voffset __ro_after_init; 50EXPORT_SYMBOL(kimage_voffset); 51 52/* 53 * Empty_zero_page is a special page that is used for zero-initialized data 54 * and COW. 55 */ 56unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 57EXPORT_SYMBOL(empty_zero_page); 58 59static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; 60static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; 61static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; 62 63static DEFINE_SPINLOCK(swapper_pgdir_lock); 64static DEFINE_MUTEX(fixmap_lock); 65 66void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 67{ 68 pgd_t *fixmap_pgdp; 69 70 spin_lock(&swapper_pgdir_lock); 71 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 72 WRITE_ONCE(*fixmap_pgdp, pgd); 73 /* 74 * We need dsb(ishst) here to ensure the page-table-walker sees 75 * our new entry before set_p?d() returns. The fixmap's 76 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 77 */ 78 pgd_clear_fixmap(); 79 spin_unlock(&swapper_pgdir_lock); 80} 81 82pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 83 unsigned long size, pgprot_t vma_prot) 84{ 85 if (!pfn_valid(pfn)) 86 return pgprot_noncached(vma_prot); 87 else if (file->f_flags & O_SYNC) 88 return pgprot_writecombine(vma_prot); 89 return vma_prot; 90} 91EXPORT_SYMBOL(phys_mem_access_prot); 92 93static phys_addr_t __init early_pgtable_alloc(int shift) 94{ 95 phys_addr_t phys; 96 void *ptr; 97 98 phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); 99 if (!phys) 100 panic("Failed to allocate page table page\n"); 101 102 /* 103 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE 104 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise 105 * any level of table. 106 */ 107 ptr = pte_set_fixmap(phys); 108 109 memset(ptr, 0, PAGE_SIZE); 110 111 /* 112 * Implicit barriers also ensure the zeroed page is visible to the page 113 * table walker 114 */ 115 pte_clear_fixmap(); 116 117 return phys; 118} 119 120static bool pgattr_change_is_safe(u64 old, u64 new) 121{ 122 /* 123 * The following mapping attributes may be updated in live 124 * kernel mappings without the need for break-before-make. 125 */ 126 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 127 128 /* creating or taking down mappings is always safe */ 129 if (old == 0 || new == 0) 130 return true; 131 132 /* live contiguous mappings may not be manipulated at all */ 133 if ((old | new) & PTE_CONT) 134 return false; 135 136 /* Transitioning from Non-Global to Global is unsafe */ 137 if (old & ~new & PTE_NG) 138 return false; 139 140 /* 141 * Changing the memory type between Normal and Normal-Tagged is safe 142 * since Tagged is considered a permission attribute from the 143 * mismatched attribute aliases perspective. 144 */ 145 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 146 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 147 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 148 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 149 mask |= PTE_ATTRINDX_MASK; 150 151 return ((old ^ new) & ~mask) == 0; 152} 153 154static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 155 phys_addr_t phys, pgprot_t prot) 156{ 157 pte_t *ptep; 158 159 ptep = pte_set_fixmap_offset(pmdp, addr); 160 do { 161 pte_t old_pte = READ_ONCE(*ptep); 162 163 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 164 165 /* 166 * After the PTE entry has been populated once, we 167 * only allow updates to the permission attributes. 168 */ 169 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 170 READ_ONCE(pte_val(*ptep)))); 171 172 phys += PAGE_SIZE; 173 } while (ptep++, addr += PAGE_SIZE, addr != end); 174 175 pte_clear_fixmap(); 176} 177 178static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 179 unsigned long end, phys_addr_t phys, 180 pgprot_t prot, 181 phys_addr_t (*pgtable_alloc)(int), 182 int flags) 183{ 184 unsigned long next; 185 pmd_t pmd = READ_ONCE(*pmdp); 186 187 BUG_ON(pmd_sect(pmd)); 188 if (pmd_none(pmd)) { 189 phys_addr_t pte_phys; 190 BUG_ON(!pgtable_alloc); 191 pte_phys = pgtable_alloc(PAGE_SHIFT); 192 __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE); 193 pmd = READ_ONCE(*pmdp); 194 } 195 BUG_ON(pmd_bad(pmd)); 196 197 do { 198 pgprot_t __prot = prot; 199 200 next = pte_cont_addr_end(addr, end); 201 202 /* use a contiguous mapping if the range is suitably aligned */ 203 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 204 (flags & NO_CONT_MAPPINGS) == 0) 205 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 206 207 init_pte(pmdp, addr, next, phys, __prot); 208 209 phys += next - addr; 210 } while (addr = next, addr != end); 211} 212 213static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 214 phys_addr_t phys, pgprot_t prot, 215 phys_addr_t (*pgtable_alloc)(int), int flags) 216{ 217 unsigned long next; 218 pmd_t *pmdp; 219 220 pmdp = pmd_set_fixmap_offset(pudp, addr); 221 do { 222 pmd_t old_pmd = READ_ONCE(*pmdp); 223 224 next = pmd_addr_end(addr, end); 225 226 /* try section mapping first */ 227 if (((addr | next | phys) & ~SECTION_MASK) == 0 && 228 (flags & NO_BLOCK_MAPPINGS) == 0) { 229 pmd_set_huge(pmdp, phys, prot); 230 231 /* 232 * After the PMD entry has been populated once, we 233 * only allow updates to the permission attributes. 234 */ 235 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 236 READ_ONCE(pmd_val(*pmdp)))); 237 } else { 238 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 239 pgtable_alloc, flags); 240 241 BUG_ON(pmd_val(old_pmd) != 0 && 242 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 243 } 244 phys += next - addr; 245 } while (pmdp++, addr = next, addr != end); 246 247 pmd_clear_fixmap(); 248} 249 250static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 251 unsigned long end, phys_addr_t phys, 252 pgprot_t prot, 253 phys_addr_t (*pgtable_alloc)(int), int flags) 254{ 255 unsigned long next; 256 pud_t pud = READ_ONCE(*pudp); 257 258 /* 259 * Check for initial section mappings in the pgd/pud. 260 */ 261 BUG_ON(pud_sect(pud)); 262 if (pud_none(pud)) { 263 phys_addr_t pmd_phys; 264 BUG_ON(!pgtable_alloc); 265 pmd_phys = pgtable_alloc(PMD_SHIFT); 266 __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE); 267 pud = READ_ONCE(*pudp); 268 } 269 BUG_ON(pud_bad(pud)); 270 271 do { 272 pgprot_t __prot = prot; 273 274 next = pmd_cont_addr_end(addr, end); 275 276 /* use a contiguous mapping if the range is suitably aligned */ 277 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 278 (flags & NO_CONT_MAPPINGS) == 0) 279 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 280 281 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 282 283 phys += next - addr; 284 } while (addr = next, addr != end); 285} 286 287static inline bool use_1G_block(unsigned long addr, unsigned long next, 288 unsigned long phys) 289{ 290 if (PAGE_SHIFT != 12) 291 return false; 292 293 if (((addr | next | phys) & ~PUD_MASK) != 0) 294 return false; 295 296 return true; 297} 298 299static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 300 phys_addr_t phys, pgprot_t prot, 301 phys_addr_t (*pgtable_alloc)(int), 302 int flags) 303{ 304 unsigned long next; 305 pud_t *pudp; 306 p4d_t *p4dp = p4d_offset(pgdp, addr); 307 p4d_t p4d = READ_ONCE(*p4dp); 308 309 if (p4d_none(p4d)) { 310 phys_addr_t pud_phys; 311 BUG_ON(!pgtable_alloc); 312 pud_phys = pgtable_alloc(PUD_SHIFT); 313 __p4d_populate(p4dp, pud_phys, PUD_TYPE_TABLE); 314 p4d = READ_ONCE(*p4dp); 315 } 316 BUG_ON(p4d_bad(p4d)); 317 318 /* 319 * No need for locking during early boot. And it doesn't work as 320 * expected with KASLR enabled. 321 */ 322 if (system_state != SYSTEM_BOOTING) 323 mutex_lock(&fixmap_lock); 324 pudp = pud_set_fixmap_offset(p4dp, addr); 325 do { 326 pud_t old_pud = READ_ONCE(*pudp); 327 328 next = pud_addr_end(addr, end); 329 330 /* 331 * For 4K granule only, attempt to put down a 1GB block 332 */ 333 if (use_1G_block(addr, next, phys) && 334 (flags & NO_BLOCK_MAPPINGS) == 0) { 335 pud_set_huge(pudp, phys, prot); 336 337 /* 338 * After the PUD entry has been populated once, we 339 * only allow updates to the permission attributes. 340 */ 341 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 342 READ_ONCE(pud_val(*pudp)))); 343 } else { 344 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 345 pgtable_alloc, flags); 346 347 BUG_ON(pud_val(old_pud) != 0 && 348 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 349 } 350 phys += next - addr; 351 } while (pudp++, addr = next, addr != end); 352 353 pud_clear_fixmap(); 354 if (system_state != SYSTEM_BOOTING) 355 mutex_unlock(&fixmap_lock); 356} 357 358static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 359 unsigned long virt, phys_addr_t size, 360 pgprot_t prot, 361 phys_addr_t (*pgtable_alloc)(int), 362 int flags) 363{ 364 unsigned long addr, end, next; 365 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 366 367 /* 368 * If the virtual and physical address don't have the same offset 369 * within a page, we cannot map the region as the caller expects. 370 */ 371 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 372 return; 373 374 phys &= PAGE_MASK; 375 addr = virt & PAGE_MASK; 376 end = PAGE_ALIGN(virt + size); 377 378 do { 379 next = pgd_addr_end(addr, end); 380 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 381 flags); 382 phys += next - addr; 383 } while (pgdp++, addr = next, addr != end); 384} 385 386static phys_addr_t __pgd_pgtable_alloc(int shift) 387{ 388 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 389 BUG_ON(!ptr); 390 391 /* Ensure the zeroed page is visible to the page table walker */ 392 dsb(ishst); 393 return __pa(ptr); 394} 395 396static phys_addr_t pgd_pgtable_alloc(int shift) 397{ 398 phys_addr_t pa = __pgd_pgtable_alloc(shift); 399 400 /* 401 * Call proper page table ctor in case later we need to 402 * call core mm functions like apply_to_page_range() on 403 * this pre-allocated page table. 404 * 405 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 406 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 407 */ 408 if (shift == PAGE_SHIFT) 409 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 410 else if (shift == PMD_SHIFT) 411 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 412 413 return pa; 414} 415 416/* 417 * This function can only be used to modify existing table entries, 418 * without allocating new levels of table. Note that this permits the 419 * creation of new section or page entries. 420 */ 421static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 422 phys_addr_t size, pgprot_t prot) 423{ 424 if (virt < PAGE_OFFSET) { 425 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 426 &phys, virt); 427 return; 428 } 429 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 430 NO_CONT_MAPPINGS); 431} 432 433void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 434 unsigned long virt, phys_addr_t size, 435 pgprot_t prot, bool page_mappings_only) 436{ 437 int flags = 0; 438 439 BUG_ON(mm == &init_mm); 440 441 if (page_mappings_only) 442 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 443 444 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 445 pgd_pgtable_alloc, flags); 446} 447 448static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 449 phys_addr_t size, pgprot_t prot) 450{ 451 if (virt < PAGE_OFFSET) { 452 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 453 &phys, virt); 454 return; 455 } 456 457 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 458 NO_CONT_MAPPINGS); 459 460 /* flush the TLBs after updating live kernel mappings */ 461 flush_tlb_kernel_range(virt, virt + size); 462} 463 464static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 465 phys_addr_t end, pgprot_t prot, int flags) 466{ 467 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 468 prot, early_pgtable_alloc, flags); 469} 470 471void __init mark_linear_text_alias_ro(void) 472{ 473 /* 474 * Remove the write permissions from the linear alias of .text/.rodata 475 */ 476 update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text), 477 (unsigned long)__init_begin - (unsigned long)_text, 478 PAGE_KERNEL_RO); 479} 480 481static bool crash_mem_map __initdata; 482 483static int __init enable_crash_mem_map(char *arg) 484{ 485 /* 486 * Proper parameter parsing is done by reserve_crashkernel(). We only 487 * need to know if the linear map has to avoid block mappings so that 488 * the crashkernel reservations can be unmapped later. 489 */ 490 crash_mem_map = true; 491 492 return 0; 493} 494early_param("crashkernel", enable_crash_mem_map); 495 496static void __init map_mem(pgd_t *pgdp) 497{ 498 phys_addr_t kernel_start = __pa_symbol(_text); 499 phys_addr_t kernel_end = __pa_symbol(__init_begin); 500 phys_addr_t start, end; 501 int flags = 0; 502 u64 i; 503 504 if (rodata_full || debug_pagealloc_enabled()) 505 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 506 507 /* 508 * Take care not to create a writable alias for the 509 * read-only text and rodata sections of the kernel image. 510 * So temporarily mark them as NOMAP to skip mappings in 511 * the following for-loop 512 */ 513 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 514 515#ifdef CONFIG_KEXEC_CORE 516 if (crash_mem_map) { 517 if (IS_ENABLED(CONFIG_ZONE_DMA) || 518 IS_ENABLED(CONFIG_ZONE_DMA32)) 519 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 520 else if (crashk_res.end) 521 memblock_mark_nomap(crashk_res.start, 522 resource_size(&crashk_res)); 523 } 524#endif 525 526 /* map all the memory banks */ 527 for_each_mem_range(i, &start, &end) { 528 if (start >= end) 529 break; 530 /* 531 * The linear map must allow allocation tags reading/writing 532 * if MTE is present. Otherwise, it has the same attributes as 533 * PAGE_KERNEL. 534 */ 535 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 536 flags); 537 } 538 539 /* 540 * Map the linear alias of the [_text, __init_begin) interval 541 * as non-executable now, and remove the write permission in 542 * mark_linear_text_alias_ro() below (which will be called after 543 * alternative patching has completed). This makes the contents 544 * of the region accessible to subsystems such as hibernate, 545 * but protects it from inadvertent modification or execution. 546 * Note that contiguous mappings cannot be remapped in this way, 547 * so we should avoid them here. 548 */ 549 __map_memblock(pgdp, kernel_start, kernel_end, 550 PAGE_KERNEL, NO_CONT_MAPPINGS); 551 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 552 553 /* 554 * Use page-level mappings here so that we can shrink the region 555 * in page granularity and put back unused memory to buddy system 556 * through /sys/kernel/kexec_crash_size interface. 557 */ 558#ifdef CONFIG_KEXEC_CORE 559 if (crash_mem_map && 560 !IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) { 561 if (crashk_res.end) { 562 __map_memblock(pgdp, crashk_res.start, 563 crashk_res.end + 1, 564 PAGE_KERNEL, 565 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 566 memblock_clear_nomap(crashk_res.start, 567 resource_size(&crashk_res)); 568 } 569 } 570#endif 571} 572 573void mark_rodata_ro(void) 574{ 575 unsigned long section_size; 576 577 /* 578 * mark .rodata as read only. Use __init_begin rather than __end_rodata 579 * to cover NOTES and EXCEPTION_TABLE. 580 */ 581 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 582 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 583 section_size, PAGE_KERNEL_RO); 584 585 debug_checkwx(); 586} 587 588static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 589 pgprot_t prot, struct vm_struct *vma, 590 int flags, unsigned long vm_flags) 591{ 592 phys_addr_t pa_start = __pa_symbol(va_start); 593 unsigned long size = va_end - va_start; 594 595 BUG_ON(!PAGE_ALIGNED(pa_start)); 596 BUG_ON(!PAGE_ALIGNED(size)); 597 598 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 599 early_pgtable_alloc, flags); 600 601 if (!(vm_flags & VM_NO_GUARD)) 602 size += PAGE_SIZE; 603 604 vma->addr = va_start; 605 vma->phys_addr = pa_start; 606 vma->size = size; 607 vma->flags = VM_MAP | vm_flags; 608 vma->caller = __builtin_return_address(0); 609 610 vm_area_add_early(vma); 611} 612 613static int __init parse_rodata(char *arg) 614{ 615 int ret = strtobool(arg, &rodata_enabled); 616 if (!ret) { 617 rodata_full = false; 618 return 0; 619 } 620 621 /* permit 'full' in addition to boolean options */ 622 if (strcmp(arg, "full")) 623 return -EINVAL; 624 625 rodata_enabled = true; 626 rodata_full = true; 627 return 0; 628} 629early_param("rodata", parse_rodata); 630 631#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 632static int __init map_entry_trampoline(void) 633{ 634 int i; 635 636 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 637 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 638 639 /* The trampoline is always mapped and can therefore be global */ 640 pgprot_val(prot) &= ~PTE_NG; 641 642 /* Map only the text into the trampoline page table */ 643 memset(tramp_pg_dir, 0, PGD_SIZE); 644 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 645 entry_tramp_text_size(), prot, 646 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 647 648 /* Map both the text and data into the kernel page table */ 649 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 650 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 651 pa_start + i * PAGE_SIZE, prot); 652 653 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 654 extern char __entry_tramp_data_start[]; 655 656 __set_fixmap(FIX_ENTRY_TRAMP_DATA, 657 __pa_symbol(__entry_tramp_data_start), 658 PAGE_KERNEL_RO); 659 } 660 661 return 0; 662} 663core_initcall(map_entry_trampoline); 664#endif 665 666/* 667 * Open coded check for BTI, only for use to determine configuration 668 * for early mappings for before the cpufeature code has run. 669 */ 670static bool arm64_early_this_cpu_has_bti(void) 671{ 672 u64 pfr1; 673 674 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 675 return false; 676 677 pfr1 = read_sysreg_s(SYS_ID_AA64PFR1_EL1); 678 return cpuid_feature_extract_unsigned_field(pfr1, 679 ID_AA64PFR1_BT_SHIFT); 680} 681 682/* 683 * Create fine-grained mappings for the kernel. 684 */ 685static void __init map_kernel(pgd_t *pgdp) 686{ 687 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 688 vmlinux_initdata, vmlinux_data; 689 690 /* 691 * External debuggers may need to write directly to the text 692 * mapping to install SW breakpoints. Allow this (only) when 693 * explicitly requested with rodata=off. 694 */ 695 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 696 697 /* 698 * If we have a CPU that supports BTI and a kernel built for 699 * BTI then mark the kernel executable text as guarded pages 700 * now so we don't have to rewrite the page tables later. 701 */ 702 if (arm64_early_this_cpu_has_bti()) 703 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 704 705 /* 706 * Only rodata will be remapped with different permissions later on, 707 * all other segments are allowed to use contiguous mappings. 708 */ 709 map_kernel_segment(pgdp, _text, _etext, text_prot, &vmlinux_text, 0, 710 VM_NO_GUARD); 711 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 712 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 713 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 714 &vmlinux_inittext, 0, VM_NO_GUARD); 715 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 716 &vmlinux_initdata, 0, VM_NO_GUARD); 717 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 718 719 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { 720 /* 721 * The fixmap falls in a separate pgd to the kernel, and doesn't 722 * live in the carveout for the swapper_pg_dir. We can simply 723 * re-use the existing dir for the fixmap. 724 */ 725 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), 726 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 727 } else if (CONFIG_PGTABLE_LEVELS > 3) { 728 pgd_t *bm_pgdp; 729 p4d_t *bm_p4dp; 730 pud_t *bm_pudp; 731 /* 732 * The fixmap shares its top level pgd entry with the kernel 733 * mapping. This can really only occur when we are running 734 * with 16k/4 levels, so we can simply reuse the pud level 735 * entry instead. 736 */ 737 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 738 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); 739 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); 740 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); 741 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 742 pud_clear_fixmap(); 743 } else { 744 BUG(); 745 } 746 747 kasan_copy_shadow(pgdp); 748} 749 750void __init paging_init(void) 751{ 752 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 753 754 map_kernel(pgdp); 755 map_mem(pgdp); 756 757 pgd_clear_fixmap(); 758 759 cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); 760 init_mm.pgd = swapper_pg_dir; 761 762 memblock_free(__pa_symbol(init_pg_dir), 763 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 764 765 memblock_allow_resize(); 766} 767 768/* 769 * Check whether a kernel address is valid (derived from arch/x86/). 770 */ 771int kern_addr_valid(unsigned long addr) 772{ 773 pgd_t *pgdp; 774 p4d_t *p4dp; 775 pud_t *pudp, pud; 776 pmd_t *pmdp, pmd; 777 pte_t *ptep, pte; 778 779 addr = arch_kasan_reset_tag(addr); 780 if ((((long)addr) >> VA_BITS) != -1UL) 781 return 0; 782 783 pgdp = pgd_offset_k(addr); 784 if (pgd_none(READ_ONCE(*pgdp))) 785 return 0; 786 787 p4dp = p4d_offset(pgdp, addr); 788 if (p4d_none(READ_ONCE(*p4dp))) 789 return 0; 790 791 pudp = pud_offset(p4dp, addr); 792 pud = READ_ONCE(*pudp); 793 if (pud_none(pud)) 794 return 0; 795 796 if (pud_sect(pud)) 797 return pfn_valid(pud_pfn(pud)); 798 799 pmdp = pmd_offset(pudp, addr); 800 pmd = READ_ONCE(*pmdp); 801 if (pmd_none(pmd)) 802 return 0; 803 804 if (pmd_sect(pmd)) 805 return pfn_valid(pmd_pfn(pmd)); 806 807 ptep = pte_offset_kernel(pmdp, addr); 808 pte = READ_ONCE(*ptep); 809 if (pte_none(pte)) 810 return 0; 811 812 return pfn_valid(pte_pfn(pte)); 813} 814 815#ifdef CONFIG_MEMORY_HOTPLUG 816static void free_hotplug_page_range(struct page *page, size_t size, 817 struct vmem_altmap *altmap) 818{ 819 if (altmap) { 820 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 821 } else { 822 WARN_ON(PageReserved(page)); 823 free_pages((unsigned long)page_address(page), get_order(size)); 824 } 825} 826 827static void free_hotplug_pgtable_page(struct page *page) 828{ 829 free_hotplug_page_range(page, PAGE_SIZE, NULL); 830} 831 832static bool pgtable_range_aligned(unsigned long start, unsigned long end, 833 unsigned long floor, unsigned long ceiling, 834 unsigned long mask) 835{ 836 start &= mask; 837 if (start < floor) 838 return false; 839 840 if (ceiling) { 841 ceiling &= mask; 842 if (!ceiling) 843 return false; 844 } 845 846 if (end - 1 > ceiling - 1) 847 return false; 848 return true; 849} 850 851static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 852 unsigned long end, bool free_mapped, 853 struct vmem_altmap *altmap) 854{ 855 pte_t *ptep, pte; 856 857 do { 858 ptep = pte_offset_kernel(pmdp, addr); 859 pte = READ_ONCE(*ptep); 860 if (pte_none(pte)) 861 continue; 862 863 WARN_ON(!pte_present(pte)); 864 pte_clear(&init_mm, addr, ptep); 865 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 866 if (free_mapped) 867 free_hotplug_page_range(pte_page(pte), 868 PAGE_SIZE, altmap); 869 } while (addr += PAGE_SIZE, addr < end); 870} 871 872static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 873 unsigned long end, bool free_mapped, 874 struct vmem_altmap *altmap) 875{ 876 unsigned long next; 877 pmd_t *pmdp, pmd; 878 879 do { 880 next = pmd_addr_end(addr, end); 881 pmdp = pmd_offset(pudp, addr); 882 pmd = READ_ONCE(*pmdp); 883 if (pmd_none(pmd)) 884 continue; 885 886 WARN_ON(!pmd_present(pmd)); 887 if (pmd_sect(pmd)) { 888 pmd_clear(pmdp); 889 890 /* 891 * One TLBI should be sufficient here as the PMD_SIZE 892 * range is mapped with a single block entry. 893 */ 894 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 895 if (free_mapped) 896 free_hotplug_page_range(pmd_page(pmd), 897 PMD_SIZE, altmap); 898 continue; 899 } 900 WARN_ON(!pmd_table(pmd)); 901 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 902 } while (addr = next, addr < end); 903} 904 905static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 906 unsigned long end, bool free_mapped, 907 struct vmem_altmap *altmap) 908{ 909 unsigned long next; 910 pud_t *pudp, pud; 911 912 do { 913 next = pud_addr_end(addr, end); 914 pudp = pud_offset(p4dp, addr); 915 pud = READ_ONCE(*pudp); 916 if (pud_none(pud)) 917 continue; 918 919 WARN_ON(!pud_present(pud)); 920 if (pud_sect(pud)) { 921 pud_clear(pudp); 922 923 /* 924 * One TLBI should be sufficient here as the PUD_SIZE 925 * range is mapped with a single block entry. 926 */ 927 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 928 if (free_mapped) 929 free_hotplug_page_range(pud_page(pud), 930 PUD_SIZE, altmap); 931 continue; 932 } 933 WARN_ON(!pud_table(pud)); 934 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 935 } while (addr = next, addr < end); 936} 937 938static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 939 unsigned long end, bool free_mapped, 940 struct vmem_altmap *altmap) 941{ 942 unsigned long next; 943 p4d_t *p4dp, p4d; 944 945 do { 946 next = p4d_addr_end(addr, end); 947 p4dp = p4d_offset(pgdp, addr); 948 p4d = READ_ONCE(*p4dp); 949 if (p4d_none(p4d)) 950 continue; 951 952 WARN_ON(!p4d_present(p4d)); 953 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 954 } while (addr = next, addr < end); 955} 956 957static void unmap_hotplug_range(unsigned long addr, unsigned long end, 958 bool free_mapped, struct vmem_altmap *altmap) 959{ 960 unsigned long next; 961 pgd_t *pgdp, pgd; 962 963 /* 964 * altmap can only be used as vmemmap mapping backing memory. 965 * In case the backing memory itself is not being freed, then 966 * altmap is irrelevant. Warn about this inconsistency when 967 * encountered. 968 */ 969 WARN_ON(!free_mapped && altmap); 970 971 do { 972 next = pgd_addr_end(addr, end); 973 pgdp = pgd_offset_k(addr); 974 pgd = READ_ONCE(*pgdp); 975 if (pgd_none(pgd)) 976 continue; 977 978 WARN_ON(!pgd_present(pgd)); 979 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 980 } while (addr = next, addr < end); 981} 982 983static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 984 unsigned long end, unsigned long floor, 985 unsigned long ceiling) 986{ 987 pte_t *ptep, pte; 988 unsigned long i, start = addr; 989 990 do { 991 ptep = pte_offset_kernel(pmdp, addr); 992 pte = READ_ONCE(*ptep); 993 994 /* 995 * This is just a sanity check here which verifies that 996 * pte clearing has been done by earlier unmap loops. 997 */ 998 WARN_ON(!pte_none(pte)); 999 } while (addr += PAGE_SIZE, addr < end); 1000 1001 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1002 return; 1003 1004 /* 1005 * Check whether we can free the pte page if the rest of the 1006 * entries are empty. Overlap with other regions have been 1007 * handled by the floor/ceiling check. 1008 */ 1009 ptep = pte_offset_kernel(pmdp, 0UL); 1010 for (i = 0; i < PTRS_PER_PTE; i++) { 1011 if (!pte_none(READ_ONCE(ptep[i]))) 1012 return; 1013 } 1014 1015 pmd_clear(pmdp); 1016 __flush_tlb_kernel_pgtable(start); 1017 free_hotplug_pgtable_page(virt_to_page(ptep)); 1018} 1019 1020static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1021 unsigned long end, unsigned long floor, 1022 unsigned long ceiling) 1023{ 1024 pmd_t *pmdp, pmd; 1025 unsigned long i, next, start = addr; 1026 1027 do { 1028 next = pmd_addr_end(addr, end); 1029 pmdp = pmd_offset(pudp, addr); 1030 pmd = READ_ONCE(*pmdp); 1031 if (pmd_none(pmd)) 1032 continue; 1033 1034 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1035 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1036 } while (addr = next, addr < end); 1037 1038 if (CONFIG_PGTABLE_LEVELS <= 2) 1039 return; 1040 1041 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1042 return; 1043 1044 /* 1045 * Check whether we can free the pmd page if the rest of the 1046 * entries are empty. Overlap with other regions have been 1047 * handled by the floor/ceiling check. 1048 */ 1049 pmdp = pmd_offset(pudp, 0UL); 1050 for (i = 0; i < PTRS_PER_PMD; i++) { 1051 if (!pmd_none(READ_ONCE(pmdp[i]))) 1052 return; 1053 } 1054 1055 pud_clear(pudp); 1056 __flush_tlb_kernel_pgtable(start); 1057 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1058} 1059 1060static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1061 unsigned long end, unsigned long floor, 1062 unsigned long ceiling) 1063{ 1064 pud_t *pudp, pud; 1065 unsigned long i, next, start = addr; 1066 1067 do { 1068 next = pud_addr_end(addr, end); 1069 pudp = pud_offset(p4dp, addr); 1070 pud = READ_ONCE(*pudp); 1071 if (pud_none(pud)) 1072 continue; 1073 1074 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1075 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1076 } while (addr = next, addr < end); 1077 1078 if (CONFIG_PGTABLE_LEVELS <= 3) 1079 return; 1080 1081 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1082 return; 1083 1084 /* 1085 * Check whether we can free the pud page if the rest of the 1086 * entries are empty. Overlap with other regions have been 1087 * handled by the floor/ceiling check. 1088 */ 1089 pudp = pud_offset(p4dp, 0UL); 1090 for (i = 0; i < PTRS_PER_PUD; i++) { 1091 if (!pud_none(READ_ONCE(pudp[i]))) 1092 return; 1093 } 1094 1095 p4d_clear(p4dp); 1096 __flush_tlb_kernel_pgtable(start); 1097 free_hotplug_pgtable_page(virt_to_page(pudp)); 1098} 1099 1100static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1101 unsigned long end, unsigned long floor, 1102 unsigned long ceiling) 1103{ 1104 unsigned long next; 1105 p4d_t *p4dp, p4d; 1106 1107 do { 1108 next = p4d_addr_end(addr, end); 1109 p4dp = p4d_offset(pgdp, addr); 1110 p4d = READ_ONCE(*p4dp); 1111 if (p4d_none(p4d)) 1112 continue; 1113 1114 WARN_ON(!p4d_present(p4d)); 1115 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1116 } while (addr = next, addr < end); 1117} 1118 1119static void free_empty_tables(unsigned long addr, unsigned long end, 1120 unsigned long floor, unsigned long ceiling) 1121{ 1122 unsigned long next; 1123 pgd_t *pgdp, pgd; 1124 1125 do { 1126 next = pgd_addr_end(addr, end); 1127 pgdp = pgd_offset_k(addr); 1128 pgd = READ_ONCE(*pgdp); 1129 if (pgd_none(pgd)) 1130 continue; 1131 1132 WARN_ON(!pgd_present(pgd)); 1133 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1134 } while (addr = next, addr < end); 1135} 1136#endif 1137 1138#ifdef CONFIG_SPARSEMEM_VMEMMAP 1139#if !ARM64_SWAPPER_USES_SECTION_MAPS 1140int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1141 struct vmem_altmap *altmap) 1142{ 1143 return vmemmap_populate_basepages(start, end, node, altmap); 1144} 1145#else /* !ARM64_SWAPPER_USES_SECTION_MAPS */ 1146int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1147 struct vmem_altmap *altmap) 1148{ 1149 unsigned long addr = start; 1150 unsigned long next; 1151 pgd_t *pgdp; 1152 p4d_t *p4dp; 1153 pud_t *pudp; 1154 pmd_t *pmdp; 1155 1156 do { 1157 next = pmd_addr_end(addr, end); 1158 1159 pgdp = vmemmap_pgd_populate(addr, node); 1160 if (!pgdp) 1161 return -ENOMEM; 1162 1163 p4dp = vmemmap_p4d_populate(pgdp, addr, node); 1164 if (!p4dp) 1165 return -ENOMEM; 1166 1167 pudp = vmemmap_pud_populate(p4dp, addr, node); 1168 if (!pudp) 1169 return -ENOMEM; 1170 1171 pmdp = pmd_offset(pudp, addr); 1172 if (pmd_none(READ_ONCE(*pmdp))) { 1173 void *p = NULL; 1174 1175 p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); 1176 if (!p) 1177 return -ENOMEM; 1178 1179 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1180 } else 1181 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1182 } while (addr = next, addr != end); 1183 1184 return 0; 1185} 1186#endif /* !ARM64_SWAPPER_USES_SECTION_MAPS */ 1187void vmemmap_free(unsigned long start, unsigned long end, 1188 struct vmem_altmap *altmap) 1189{ 1190#ifdef CONFIG_MEMORY_HOTPLUG 1191 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1192 1193 unmap_hotplug_range(start, end, true, altmap); 1194 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1195#endif 1196} 1197#endif /* CONFIG_SPARSEMEM_VMEMMAP */ 1198 1199static inline pud_t * fixmap_pud(unsigned long addr) 1200{ 1201 pgd_t *pgdp = pgd_offset_k(addr); 1202 p4d_t *p4dp = p4d_offset(pgdp, addr); 1203 p4d_t p4d = READ_ONCE(*p4dp); 1204 1205 BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); 1206 1207 return pud_offset_kimg(p4dp, addr); 1208} 1209 1210static inline pmd_t * fixmap_pmd(unsigned long addr) 1211{ 1212 pud_t *pudp = fixmap_pud(addr); 1213 pud_t pud = READ_ONCE(*pudp); 1214 1215 BUG_ON(pud_none(pud) || pud_bad(pud)); 1216 1217 return pmd_offset_kimg(pudp, addr); 1218} 1219 1220static inline pte_t * fixmap_pte(unsigned long addr) 1221{ 1222 return &bm_pte[pte_index(addr)]; 1223} 1224 1225/* 1226 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 1227 * directly on kernel symbols (bm_p*d). This function is called too early to use 1228 * lm_alias so __p*d_populate functions must be used to populate with the 1229 * physical address from __pa_symbol. 1230 */ 1231void __init early_fixmap_init(void) 1232{ 1233 pgd_t *pgdp; 1234 p4d_t *p4dp, p4d; 1235 pud_t *pudp; 1236 pmd_t *pmdp; 1237 unsigned long addr = FIXADDR_START; 1238 1239 pgdp = pgd_offset_k(addr); 1240 p4dp = p4d_offset(pgdp, addr); 1241 p4d = READ_ONCE(*p4dp); 1242 if (CONFIG_PGTABLE_LEVELS > 3 && 1243 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { 1244 /* 1245 * We only end up here if the kernel mapping and the fixmap 1246 * share the top level pgd entry, which should only happen on 1247 * 16k/4 levels configurations. 1248 */ 1249 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 1250 pudp = pud_offset_kimg(p4dp, addr); 1251 } else { 1252 if (p4d_none(p4d)) 1253 __p4d_populate(p4dp, __pa_symbol(bm_pud), PUD_TYPE_TABLE); 1254 pudp = fixmap_pud(addr); 1255 } 1256 if (pud_none(READ_ONCE(*pudp))) 1257 __pud_populate(pudp, __pa_symbol(bm_pmd), PMD_TYPE_TABLE); 1258 pmdp = fixmap_pmd(addr); 1259 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 1260 1261 /* 1262 * The boot-ioremap range spans multiple pmds, for which 1263 * we are not prepared: 1264 */ 1265 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 1266 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 1267 1268 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 1269 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 1270 WARN_ON(1); 1271 pr_warn("pmdp %p != %p, %p\n", 1272 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 1273 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 1274 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 1275 fix_to_virt(FIX_BTMAP_BEGIN)); 1276 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 1277 fix_to_virt(FIX_BTMAP_END)); 1278 1279 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 1280 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 1281 } 1282} 1283 1284/* 1285 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 1286 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 1287 */ 1288void __set_fixmap(enum fixed_addresses idx, 1289 phys_addr_t phys, pgprot_t flags) 1290{ 1291 unsigned long addr = __fix_to_virt(idx); 1292 pte_t *ptep; 1293 1294 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 1295 1296 ptep = fixmap_pte(addr); 1297 1298 if (pgprot_val(flags)) { 1299 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 1300 } else { 1301 pte_clear(&init_mm, addr, ptep); 1302 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 1303 } 1304} 1305 1306void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 1307{ 1308 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 1309 int offset; 1310 void *dt_virt; 1311 1312 /* 1313 * Check whether the physical FDT address is set and meets the minimum 1314 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 1315 * at least 8 bytes so that we can always access the magic and size 1316 * fields of the FDT header after mapping the first chunk, double check 1317 * here if that is indeed the case. 1318 */ 1319 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 1320 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 1321 return NULL; 1322 1323 /* 1324 * Make sure that the FDT region can be mapped without the need to 1325 * allocate additional translation table pages, so that it is safe 1326 * to call create_mapping_noalloc() this early. 1327 * 1328 * On 64k pages, the FDT will be mapped using PTEs, so we need to 1329 * be in the same PMD as the rest of the fixmap. 1330 * On 4k pages, we'll use section mappings for the FDT so we only 1331 * have to be in the same PUD. 1332 */ 1333 BUILD_BUG_ON(dt_virt_base % SZ_2M); 1334 1335 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 1336 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 1337 1338 offset = dt_phys % SWAPPER_BLOCK_SIZE; 1339 dt_virt = (void *)dt_virt_base + offset; 1340 1341 /* map the first chunk so we can read the size from the header */ 1342 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 1343 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 1344 1345 if (fdt_magic(dt_virt) != FDT_MAGIC) 1346 return NULL; 1347 1348 *size = fdt_totalsize(dt_virt); 1349 if (*size > MAX_FDT_SIZE) 1350 return NULL; 1351 1352 if (offset + *size > SWAPPER_BLOCK_SIZE) 1353 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 1354 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 1355 1356 return dt_virt; 1357} 1358 1359int __init arch_ioremap_p4d_supported(void) 1360{ 1361 return 0; 1362} 1363 1364int __init arch_ioremap_pud_supported(void) 1365{ 1366 /* 1367 * Only 4k granule supports level 1 block mappings. 1368 * SW table walks can't handle removal of intermediate entries. 1369 */ 1370 return IS_ENABLED(CONFIG_ARM64_4K_PAGES) && 1371 !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); 1372} 1373 1374int __init arch_ioremap_pmd_supported(void) 1375{ 1376 /* See arch_ioremap_pud_supported() */ 1377 return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS); 1378} 1379 1380int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1381{ 1382 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1383 1384 /* Only allow permission changes for now */ 1385 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1386 pud_val(new_pud))) 1387 return 0; 1388 1389 VM_BUG_ON(phys & ~PUD_MASK); 1390 set_pud(pudp, new_pud); 1391 return 1; 1392} 1393 1394int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1395{ 1396 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1397 1398 /* Only allow permission changes for now */ 1399 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1400 pmd_val(new_pmd))) 1401 return 0; 1402 1403 VM_BUG_ON(phys & ~PMD_MASK); 1404 set_pmd(pmdp, new_pmd); 1405 return 1; 1406} 1407 1408int pud_clear_huge(pud_t *pudp) 1409{ 1410 if (!pud_sect(READ_ONCE(*pudp))) 1411 return 0; 1412 pud_clear(pudp); 1413 return 1; 1414} 1415 1416int pmd_clear_huge(pmd_t *pmdp) 1417{ 1418 if (!pmd_sect(READ_ONCE(*pmdp))) 1419 return 0; 1420 pmd_clear(pmdp); 1421 return 1; 1422} 1423 1424int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1425{ 1426 pte_t *table; 1427 pmd_t pmd; 1428 1429 pmd = READ_ONCE(*pmdp); 1430 1431 if (!pmd_table(pmd)) { 1432 VM_WARN_ON(1); 1433 return 1; 1434 } 1435 1436 table = pte_offset_kernel(pmdp, addr); 1437 pmd_clear(pmdp); 1438 __flush_tlb_kernel_pgtable(addr); 1439 pte_free_kernel(NULL, table); 1440 return 1; 1441} 1442 1443int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1444{ 1445 pmd_t *table; 1446 pmd_t *pmdp; 1447 pud_t pud; 1448 unsigned long next, end; 1449 1450 pud = READ_ONCE(*pudp); 1451 1452 if (!pud_table(pud)) { 1453 VM_WARN_ON(1); 1454 return 1; 1455 } 1456 1457 table = pmd_offset(pudp, addr); 1458 pmdp = table; 1459 next = addr; 1460 end = addr + PUD_SIZE; 1461 do { 1462 pmd_free_pte_page(pmdp, next); 1463 } while (pmdp++, next += PMD_SIZE, next != end); 1464 1465 pud_clear(pudp); 1466 __flush_tlb_kernel_pgtable(addr); 1467 pmd_free(NULL, table); 1468 return 1; 1469} 1470 1471int p4d_free_pud_page(p4d_t *p4d, unsigned long addr) 1472{ 1473 return 0; /* Don't attempt a block mapping */ 1474} 1475 1476#ifdef CONFIG_MEMORY_HOTPLUG 1477static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1478{ 1479 unsigned long end = start + size; 1480 1481 WARN_ON(pgdir != init_mm.pgd); 1482 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1483 1484 unmap_hotplug_range(start, end, false, NULL); 1485 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1486} 1487 1488static bool inside_linear_region(u64 start, u64 size) 1489{ 1490 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1491 u64 end_linear_pa = __pa(PAGE_END - 1); 1492 1493 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1494 /* 1495 * Check for a wrap, it is possible because of randomized linear 1496 * mapping the start physical address is actually bigger than 1497 * the end physical address. In this case set start to zero 1498 * because [0, end_linear_pa] range must still be able to cover 1499 * all addressable physical addresses. 1500 */ 1501 if (start_linear_pa > end_linear_pa) 1502 start_linear_pa = 0; 1503 } 1504 1505 WARN_ON(start_linear_pa > end_linear_pa); 1506 1507 /* 1508 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1509 * accommodating both its ends but excluding PAGE_END. Max physical 1510 * range which can be mapped inside this linear mapping range, must 1511 * also be derived from its end points. 1512 */ 1513 return start >= start_linear_pa && (start + size - 1) <= end_linear_pa; 1514} 1515 1516int arch_add_memory(int nid, u64 start, u64 size, 1517 struct mhp_params *params) 1518{ 1519 int ret, flags = 0; 1520 1521 if (!inside_linear_region(start, size)) { 1522 pr_err("[%llx %llx] is outside linear mapping region\n", start, start + size); 1523 return -EINVAL; 1524 } 1525 1526 if (rodata_full || debug_pagealloc_enabled()) 1527 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1528 1529 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1530 size, params->pgprot, __pgd_pgtable_alloc, 1531 flags); 1532 1533 memblock_clear_nomap(start, size); 1534 1535 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1536 params); 1537 if (ret) 1538 __remove_pgd_mapping(swapper_pg_dir, 1539 __phys_to_virt(start), size); 1540 else { 1541 max_pfn = PFN_UP(start + size); 1542 max_low_pfn = max_pfn; 1543 } 1544 1545 return ret; 1546} 1547 1548void arch_remove_memory(int nid, u64 start, u64 size, 1549 struct vmem_altmap *altmap) 1550{ 1551 unsigned long start_pfn = start >> PAGE_SHIFT; 1552 unsigned long nr_pages = size >> PAGE_SHIFT; 1553 1554 __remove_pages(start_pfn, nr_pages, altmap); 1555 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1556} 1557 1558/* 1559 * This memory hotplug notifier helps prevent boot memory from being 1560 * inadvertently removed as it blocks pfn range offlining process in 1561 * __offline_pages(). Hence this prevents both offlining as well as 1562 * removal process for boot memory which is initially always online. 1563 * In future if and when boot memory could be removed, this notifier 1564 * should be dropped and free_hotplug_page_range() should handle any 1565 * reserved pages allocated during boot. 1566 */ 1567static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1568 unsigned long action, void *data) 1569{ 1570 struct mem_section *ms; 1571 struct memory_notify *arg = data; 1572 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1573 unsigned long pfn = arg->start_pfn; 1574 1575 if (action != MEM_GOING_OFFLINE) 1576 return NOTIFY_OK; 1577 1578 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1579 ms = __pfn_to_section(pfn); 1580 if (early_section(ms)) 1581 return NOTIFY_BAD; 1582 } 1583 return NOTIFY_OK; 1584} 1585 1586static struct notifier_block prevent_bootmem_remove_nb = { 1587 .notifier_call = prevent_bootmem_remove_notifier, 1588}; 1589 1590static int __init prevent_bootmem_remove_init(void) 1591{ 1592 return register_memory_notifier(&prevent_bootmem_remove_nb); 1593} 1594device_initcall(prevent_bootmem_remove_init); 1595#endif 1596