arch/arm64/mm/mmu.c

   1 /*
   2  * Based on arch/arm/mm/mmu.c
   3  *
   4  * Copyright (C) 1995-2005 Russell King
   5  * Copyright (C) 2012 ARM Ltd.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <linux/cache.h>
  21 #include <linux/export.h>
  22 #include <linux/kernel.h>
  23 #include <linux/errno.h>
  24 #include <linux/init.h>
  25 #include <linux/libfdt.h>
  26 #include <linux/mman.h>
  27 #include <linux/nodemask.h>
  28 #include <linux/memblock.h>
  29 #include <linux/fs.h>
  30 #include <linux/io.h>
  31 #include <linux/mm.h>
  32
  33 #include <asm/barrier.h>
  34 #include <asm/cputype.h>
  35 #include <asm/fixmap.h>
  36 #include <asm/kasan.h>
  37 #include <asm/kernel-pgtable.h>
  38 #include <asm/sections.h>
  39 #include <asm/setup.h>
  40 #include <asm/sizes.h>
  41 #include <asm/tlb.h>
  42 #include <asm/memblock.h>
  43 #include <asm/mmu_context.h>
  44 #include <asm/ptdump.h>
  45
  46 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
  47
  48 u64 kimage_voffset __ro_after_init;
  49 EXPORT_SYMBOL(kimage_voffset);
  50
  51 /*
  52  * Empty_zero_page is a special page that is used for zero-initialized data
  53  * and COW.
  54  */
  55 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
  56 EXPORT_SYMBOL(empty_zero_page);
  57
  58 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
  59 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
  60 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
  61
  62 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
  63                               unsigned long size, pgprot_t vma_prot)
  64 {
  65         if (!pfn_valid(pfn))
  66                 return pgprot_noncached(vma_prot);
  67         else if (file->f_flags & O_SYNC)
  68                 return pgprot_writecombine(vma_prot);
  69         return vma_prot;
  70 }
  71 EXPORT_SYMBOL(phys_mem_access_prot);
  72
  73 static phys_addr_t __init early_pgtable_alloc(void)
  74 {
  75         phys_addr_t phys;
  76         void *ptr;
  77
  78         phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
  79
  80         /*
  81          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
  82          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
  83          * any level of table.
  84          */
  85         ptr = pte_set_fixmap(phys);
  86
  87         memset(ptr, 0, PAGE_SIZE);
  88
  89         /*
  90          * Implicit barriers also ensure the zeroed page is visible to the page
  91          * table walker
  92          */
  93         pte_clear_fixmap();
  94
  95         return phys;
  96 }
  97
  98 static bool pgattr_change_is_safe(u64 old, u64 new)
  99 {
 100         /*
 101          * The following mapping attributes may be updated in live
 102          * kernel mappings without the need for break-before-make.
 103          */
 104         static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE;
 105
 106         return old  == 0 || new  == 0 || ((old ^ new) & ~mask) == 0;
 107 }
 108
 109 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 110                                   unsigned long end, unsigned long pfn,
 111                                   pgprot_t prot,
 112                                   phys_addr_t (*pgtable_alloc)(void))
 113 {
 114         pte_t *pte;
 115
 116         BUG_ON(pmd_sect(*pmd));
 117         if (pmd_none(*pmd)) {
 118                 phys_addr_t pte_phys;
 119                 BUG_ON(!pgtable_alloc);
 120                 pte_phys = pgtable_alloc();
 121                 pte = pte_set_fixmap(pte_phys);
 122                 __pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
 123                 pte_clear_fixmap();
 124         }
 125         BUG_ON(pmd_bad(*pmd));
 126
 127         pte = pte_set_fixmap_offset(pmd, addr);
 128         do {
 129                 pte_t old_pte = *pte;
 130
 131                 set_pte(pte, pfn_pte(pfn, prot));
 132                 pfn++;
 133
 134                 /*
 135                  * After the PTE entry has been populated once, we
 136                  * only allow updates to the permission attributes.
 137                  */
 138                 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), pte_val(*pte)));
 139
 140         } while (pte++, addr += PAGE_SIZE, addr != end);
 141
 142         pte_clear_fixmap();
 143 }
 144
 145 static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 146                                   phys_addr_t phys, pgprot_t prot,
 147                                   phys_addr_t (*pgtable_alloc)(void),
 148                                   bool page_mappings_only)
 149 {
 150         pmd_t *pmd;
 151         unsigned long next;
 152
 153         /*
 154          * Check for initial section mappings in the pgd/pud and remove them.
 155          */
 156         BUG_ON(pud_sect(*pud));
 157         if (pud_none(*pud)) {
 158                 phys_addr_t pmd_phys;
 159                 BUG_ON(!pgtable_alloc);
 160                 pmd_phys = pgtable_alloc();
 161                 pmd = pmd_set_fixmap(pmd_phys);
 162                 __pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
 163                 pmd_clear_fixmap();
 164         }
 165         BUG_ON(pud_bad(*pud));
 166
 167         pmd = pmd_set_fixmap_offset(pud, addr);
 168         do {
 169                 pmd_t old_pmd = *pmd;
 170
 171                 next = pmd_addr_end(addr, end);
 172
 173                 /* try section mapping first */
 174                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
 175                       !page_mappings_only) {
 176                         pmd_set_huge(pmd, phys, prot);
 177
 178                         /*
 179                          * After the PMD entry has been populated once, we
 180                          * only allow updates to the permission attributes.
 181                          */
 182                         BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
 183                                                       pmd_val(*pmd)));
 184                 } else {
 185                         alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
 186                                        prot, pgtable_alloc);
 187
 188                         BUG_ON(pmd_val(old_pmd) != 0 &&
 189                                pmd_val(old_pmd) != pmd_val(*pmd));
 190                 }
 191                 phys += next - addr;
 192         } while (pmd++, addr = next, addr != end);
 193
 194         pmd_clear_fixmap();
 195 }
 196
 197 static inline bool use_1G_block(unsigned long addr, unsigned long next,
 198                         unsigned long phys)
 199 {
 200         if (PAGE_SHIFT != 12)
 201                 return false;
 202
 203         if (((addr | next | phys) & ~PUD_MASK) != 0)
 204                 return false;
 205
 206         return true;
 207 }
 208
 209 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 210                                   phys_addr_t phys, pgprot_t prot,
 211                                   phys_addr_t (*pgtable_alloc)(void),
 212                                   bool page_mappings_only)
 213 {
 214         pud_t *pud;
 215         unsigned long next;
 216
 217         if (pgd_none(*pgd)) {
 218                 phys_addr_t pud_phys;
 219                 BUG_ON(!pgtable_alloc);
 220                 pud_phys = pgtable_alloc();
 221                 __pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
 222         }
 223         BUG_ON(pgd_bad(*pgd));
 224
 225         pud = pud_set_fixmap_offset(pgd, addr);
 226         do {
 227                 pud_t old_pud = *pud;
 228
 229                 next = pud_addr_end(addr, end);
 230
 231                 /*
 232                  * For 4K granule only, attempt to put down a 1GB block
 233                  */
 234                 if (use_1G_block(addr, next, phys) && !page_mappings_only) {
 235                         pud_set_huge(pud, phys, prot);
 236
 237                         /*
 238                          * After the PUD entry has been populated once, we
 239                          * only allow updates to the permission attributes.
 240                          */
 241                         BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
 242                                                       pud_val(*pud)));
 243                 } else {
 244                         alloc_init_pmd(pud, addr, next, phys, prot,
 245                                        pgtable_alloc, page_mappings_only);
 246
 247                         BUG_ON(pud_val(old_pud) != 0 &&
 248                                pud_val(old_pud) != pud_val(*pud));
 249                 }
 250                 phys += next - addr;
 251         } while (pud++, addr = next, addr != end);
 252
 253         pud_clear_fixmap();
 254 }
 255
 256 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 257                                  unsigned long virt, phys_addr_t size,
 258                                  pgprot_t prot,
 259                                  phys_addr_t (*pgtable_alloc)(void),
 260                                  bool page_mappings_only)
 261 {
 262         unsigned long addr, length, end, next;
 263         pgd_t *pgd = pgd_offset_raw(pgdir, virt);
 264
 265         /*
 266          * If the virtual and physical address don't have the same offset
 267          * within a page, we cannot map the region as the caller expects.
 268          */
 269         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
 270                 return;
 271
 272         phys &= PAGE_MASK;
 273         addr = virt & PAGE_MASK;
 274         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
 275
 276         end = addr + length;
 277         do {
 278                 next = pgd_addr_end(addr, end);
 279                 alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc,
 280                                page_mappings_only);
 281                 phys += next - addr;
 282         } while (pgd++, addr = next, addr != end);
 283 }
 284
 285 static phys_addr_t pgd_pgtable_alloc(void)
 286 {
 287         void *ptr = (void *)__get_free_page(PGALLOC_GFP);
 288         if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))
 289                 BUG();
 290
 291         /* Ensure the zeroed page is visible to the page table walker */
 292         dsb(ishst);
 293         return __pa(ptr);
 294 }
 295
 296 /*
 297  * This function can only be used to modify existing table entries,
 298  * without allocating new levels of table. Note that this permits the
 299  * creation of new section or page entries.
 300  */
 301 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 302                                   phys_addr_t size, pgprot_t prot)
 303 {
 304         if (virt < VMALLOC_START) {
 305                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 306                         &phys, virt);
 307                 return;
 308         }
 309         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, false);
 310 }
 311
 312 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 313                                unsigned long virt, phys_addr_t size,
 314                                pgprot_t prot, bool page_mappings_only)
 315 {
 316         BUG_ON(mm == &init_mm);
 317
 318         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
 319                              pgd_pgtable_alloc, page_mappings_only);
 320 }
 321
 322 static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
 323                                 phys_addr_t size, pgprot_t prot)
 324 {
 325         if (virt < VMALLOC_START) {
 326                 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
 327                         &phys, virt);
 328                 return;
 329         }
 330
 331         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 332                              NULL, debug_pagealloc_enabled());
 333
 334         /* flush the TLBs after updating live kernel mappings */
 335         flush_tlb_kernel_range(virt, virt + size);
 336 }
 337
 338 static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
 339 {
 340         phys_addr_t kernel_start = __pa_symbol(_text);
 341         phys_addr_t kernel_end = __pa_symbol(__init_begin);
 342
 343         /*
 344          * Take care not to create a writable alias for the
 345          * read-only text and rodata sections of the kernel image.
 346          */
 347
 348         /* No overlap with the kernel text/rodata */
 349         if (end < kernel_start || start >= kernel_end) {
 350                 __create_pgd_mapping(pgd, start, __phys_to_virt(start),
 351                                      end - start, PAGE_KERNEL,
 352                                      early_pgtable_alloc,
 353                                      debug_pagealloc_enabled());
 354                 return;
 355         }
 356
 357         /*
 358          * This block overlaps the kernel text/rodata mappings.
 359          * Map the portion(s) which don't overlap.
 360          */
 361         if (start < kernel_start)
 362                 __create_pgd_mapping(pgd, start,
 363                                      __phys_to_virt(start),
 364                                      kernel_start - start, PAGE_KERNEL,
 365                                      early_pgtable_alloc,
 366                                      debug_pagealloc_enabled());
 367         if (kernel_end < end)
 368                 __create_pgd_mapping(pgd, kernel_end,
 369                                      __phys_to_virt(kernel_end),
 370                                      end - kernel_end, PAGE_KERNEL,
 371                                      early_pgtable_alloc,
 372                                      debug_pagealloc_enabled());
 373
 374         /*
 375          * Map the linear alias of the [_text, __init_begin) interval
 376          * as non-executable now, and remove the write permission in
 377          * mark_linear_text_alias_ro() below (which will be called after
 378          * alternative patching has completed). This makes the contents
 379          * of the region accessible to subsystems such as hibernate,
 380          * but protects it from inadvertent modification or execution.
 381          */
 382         __create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
 383                              kernel_end - kernel_start, PAGE_KERNEL,
 384                              early_pgtable_alloc, debug_pagealloc_enabled());
 385 }
 386
 387 void __init mark_linear_text_alias_ro(void)
 388 {
 389         /*
 390          * Remove the write permissions from the linear alias of .text/.rodata
 391          */
 392         update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text),
 393                             (unsigned long)__init_begin - (unsigned long)_text,
 394                             PAGE_KERNEL_RO);
 395 }
 396
 397 static void __init map_mem(pgd_t *pgd)
 398 {
 399         struct memblock_region *reg;
 400
 401         /* map all the memory banks */
 402         for_each_memblock(memory, reg) {
 403                 phys_addr_t start = reg->base;
 404                 phys_addr_t end = start + reg->size;
 405
 406                 if (start >= end)
 407                         break;
 408                 if (memblock_is_nomap(reg))
 409                         continue;
 410
 411                 __map_memblock(pgd, start, end);
 412         }
 413 }
 414
 415 void mark_rodata_ro(void)
 416 {
 417         unsigned long section_size;
 418
 419         section_size = (unsigned long)_etext - (unsigned long)_text;
 420         update_mapping_prot(__pa_symbol(_text), (unsigned long)_text,
 421                             section_size, PAGE_KERNEL_ROX);
 422         /*
 423          * mark .rodata as read only. Use __init_begin rather than __end_rodata
 424          * to cover NOTES and EXCEPTION_TABLE.
 425          */
 426         section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
 427         update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
 428                             section_size, PAGE_KERNEL_RO);
 429
 430         debug_checkwx();
 431 }
 432
 433 static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
 434                                       pgprot_t prot, struct vm_struct *vma)
 435 {
 436         phys_addr_t pa_start = __pa_symbol(va_start);
 437         unsigned long size = va_end - va_start;
 438
 439         BUG_ON(!PAGE_ALIGNED(pa_start));
 440         BUG_ON(!PAGE_ALIGNED(size));
 441
 442         __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
 443                              early_pgtable_alloc, debug_pagealloc_enabled());
 444
 445         vma->addr       = va_start;
 446         vma->phys_addr  = pa_start;
 447         vma->size       = size;
 448         vma->flags      = VM_MAP;
 449         vma->caller     = __builtin_return_address(0);
 450
 451         vm_area_add_early(vma);
 452 }
 453
 454 /*
 455  * Create fine-grained mappings for the kernel.
 456  */
 457 static void __init map_kernel(pgd_t *pgd)
 458 {
 459         static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
 460
 461         map_kernel_segment(pgd, _text, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
 462         map_kernel_segment(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata);
 463         map_kernel_segment(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
 464                            &vmlinux_init);
 465         map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
 466
 467         if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
 468                 /*
 469                  * The fixmap falls in a separate pgd to the kernel, and doesn't
 470                  * live in the carveout for the swapper_pg_dir. We can simply
 471                  * re-use the existing dir for the fixmap.
 472                  */
 473                 set_pgd(pgd_offset_raw(pgd, FIXADDR_START),
 474                         *pgd_offset_k(FIXADDR_START));
 475         } else if (CONFIG_PGTABLE_LEVELS > 3) {
 476                 /*
 477                  * The fixmap shares its top level pgd entry with the kernel
 478                  * mapping. This can really only occur when we are running
 479                  * with 16k/4 levels, so we can simply reuse the pud level
 480                  * entry instead.
 481                  */
 482                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 483                 set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
 484                         __pud(__pa_symbol(bm_pmd) | PUD_TYPE_TABLE));
 485                 pud_clear_fixmap();
 486         } else {
 487                 BUG();
 488         }
 489
 490         kasan_copy_shadow(pgd);
 491 }
 492
 493 /*
 494  * paging_init() sets up the page tables, initialises the zone memory
 495  * maps and sets up the zero page.
 496  */
 497 void __init paging_init(void)
 498 {
 499         phys_addr_t pgd_phys = early_pgtable_alloc();
 500         pgd_t *pgd = pgd_set_fixmap(pgd_phys);
 501
 502         map_kernel(pgd);
 503         map_mem(pgd);
 504
 505         /*
 506          * We want to reuse the original swapper_pg_dir so we don't have to
 507          * communicate the new address to non-coherent secondaries in
 508          * secondary_entry, and so cpu_switch_mm can generate the address with
 509          * adrp+add rather than a load from some global variable.
 510          *
 511          * To do this we need to go via a temporary pgd.
 512          */
 513         cpu_replace_ttbr1(__va(pgd_phys));
 514         memcpy(swapper_pg_dir, pgd, PGD_SIZE);
 515         cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 516
 517         pgd_clear_fixmap();
 518         memblock_free(pgd_phys, PAGE_SIZE);
 519
 520         /*
 521          * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
 522          * allocated with it.
 523          */
 524         memblock_free(__pa_symbol(swapper_pg_dir) + PAGE_SIZE,
 525                       SWAPPER_DIR_SIZE - PAGE_SIZE);
 526 }
 527
 528 /*
 529  * Check whether a kernel address is valid (derived from arch/x86/).
 530  */
 531 int kern_addr_valid(unsigned long addr)
 532 {
 533         pgd_t *pgd;
 534         pud_t *pud;
 535         pmd_t *pmd;
 536         pte_t *pte;
 537
 538         if ((((long)addr) >> VA_BITS) != -1UL)
 539                 return 0;
 540
 541         pgd = pgd_offset_k(addr);
 542         if (pgd_none(*pgd))
 543                 return 0;
 544
 545         pud = pud_offset(pgd, addr);
 546         if (pud_none(*pud))
 547                 return 0;
 548
 549         if (pud_sect(*pud))
 550                 return pfn_valid(pud_pfn(*pud));
 551
 552         pmd = pmd_offset(pud, addr);
 553         if (pmd_none(*pmd))
 554                 return 0;
 555
 556         if (pmd_sect(*pmd))
 557                 return pfn_valid(pmd_pfn(*pmd));
 558
 559         pte = pte_offset_kernel(pmd, addr);
 560         if (pte_none(*pte))
 561                 return 0;
 562
 563         return pfn_valid(pte_pfn(*pte));
 564 }
 565 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 566 #if !ARM64_SWAPPER_USES_SECTION_MAPS
 567 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 568 {
 569         return vmemmap_populate_basepages(start, end, node);
 570 }
 571 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
 572 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 573 {
 574         unsigned long addr = start;
 575         unsigned long next;
 576         pgd_t *pgd;
 577         pud_t *pud;
 578         pmd_t *pmd;
 579
 580         do {
 581                 next = pmd_addr_end(addr, end);
 582
 583                 pgd = vmemmap_pgd_populate(addr, node);
 584                 if (!pgd)
 585                         return -ENOMEM;
 586
 587                 pud = vmemmap_pud_populate(pgd, addr, node);
 588                 if (!pud)
 589                         return -ENOMEM;
 590
 591                 pmd = pmd_offset(pud, addr);
 592                 if (pmd_none(*pmd)) {
 593                         void *p = NULL;
 594
 595                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
 596                         if (!p)
 597                                 return -ENOMEM;
 598
 599                         set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
 600                 } else
 601                         vmemmap_verify((pte_t *)pmd, node, addr, next);
 602         } while (addr = next, addr != end);
 603
 604         return 0;
 605 }
 606 #endif  /* CONFIG_ARM64_64K_PAGES */
 607 void vmemmap_free(unsigned long start, unsigned long end)
 608 {
 609 }
 610 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
 611
 612 static inline pud_t * fixmap_pud(unsigned long addr)
 613 {
 614         pgd_t *pgd = pgd_offset_k(addr);
 615
 616         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 617
 618         return pud_offset_kimg(pgd, addr);
 619 }
 620
 621 static inline pmd_t * fixmap_pmd(unsigned long addr)
 622 {
 623         pud_t *pud = fixmap_pud(addr);
 624
 625         BUG_ON(pud_none(*pud) || pud_bad(*pud));
 626
 627         return pmd_offset_kimg(pud, addr);
 628 }
 629
 630 static inline pte_t * fixmap_pte(unsigned long addr)
 631 {
 632         return &bm_pte[pte_index(addr)];
 633 }
 634
 635 /*
 636  * The p*d_populate functions call virt_to_phys implicitly so they can't be used
 637  * directly on kernel symbols (bm_p*d). This function is called too early to use
 638  * lm_alias so __p*d_populate functions must be used to populate with the
 639  * physical address from __pa_symbol.
 640  */
 641 void __init early_fixmap_init(void)
 642 {
 643         pgd_t *pgd;
 644         pud_t *pud;
 645         pmd_t *pmd;
 646         unsigned long addr = FIXADDR_START;
 647
 648         pgd = pgd_offset_k(addr);
 649         if (CONFIG_PGTABLE_LEVELS > 3 &&
 650             !(pgd_none(*pgd) || pgd_page_paddr(*pgd) == __pa_symbol(bm_pud))) {
 651                 /*
 652                  * We only end up here if the kernel mapping and the fixmap
 653                  * share the top level pgd entry, which should only happen on
 654                  * 16k/4 levels configurations.
 655                  */
 656                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 657                 pud = pud_offset_kimg(pgd, addr);
 658         } else {
 659                 if (pgd_none(*pgd))
 660                         __pgd_populate(pgd, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
 661                 pud = fixmap_pud(addr);
 662         }
 663         if (pud_none(*pud))
 664                 __pud_populate(pud, __pa_symbol(bm_pmd), PMD_TYPE_TABLE);
 665         pmd = fixmap_pmd(addr);
 666         __pmd_populate(pmd, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
 667
 668         /*
 669          * The boot-ioremap range spans multiple pmds, for which
 670          * we are not prepared:
 671          */
 672         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 673                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 674
 675         if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
 676              || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 677                 WARN_ON(1);
 678                 pr_warn("pmd %p != %p, %p\n",
 679                         pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
 680                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
 681                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 682                         fix_to_virt(FIX_BTMAP_BEGIN));
 683                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 684                         fix_to_virt(FIX_BTMAP_END));
 685
 686                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 687                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
 688         }
 689 }
 690
 691 void __set_fixmap(enum fixed_addresses idx,
 692                                phys_addr_t phys, pgprot_t flags)
 693 {
 694         unsigned long addr = __fix_to_virt(idx);
 695         pte_t *pte;
 696
 697         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 698
 699         pte = fixmap_pte(addr);
 700
 701         if (pgprot_val(flags)) {
 702                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 703         } else {
 704                 pte_clear(&init_mm, addr, pte);
 705                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 706         }
 707 }
 708
 709 void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 710 {
 711         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
 712         int offset;
 713         void *dt_virt;
 714
 715         /*
 716          * Check whether the physical FDT address is set and meets the minimum
 717          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
 718          * at least 8 bytes so that we can always access the magic and size
 719          * fields of the FDT header after mapping the first chunk, double check
 720          * here if that is indeed the case.
 721          */
 722         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 723         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
 724                 return NULL;
 725
 726         /*
 727          * Make sure that the FDT region can be mapped without the need to
 728          * allocate additional translation table pages, so that it is safe
 729          * to call create_mapping_noalloc() this early.
 730          *
 731          * On 64k pages, the FDT will be mapped using PTEs, so we need to
 732          * be in the same PMD as the rest of the fixmap.
 733          * On 4k pages, we'll use section mappings for the FDT so we only
 734          * have to be in the same PUD.
 735          */
 736         BUILD_BUG_ON(dt_virt_base % SZ_2M);
 737
 738         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
 739                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
 740
 741         offset = dt_phys % SWAPPER_BLOCK_SIZE;
 742         dt_virt = (void *)dt_virt_base + offset;
 743
 744         /* map the first chunk so we can read the size from the header */
 745         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
 746                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 747
 748         if (fdt_magic(dt_virt) != FDT_MAGIC)
 749                 return NULL;
 750
 751         *size = fdt_totalsize(dt_virt);
 752         if (*size > MAX_FDT_SIZE)
 753                 return NULL;
 754
 755         if (offset + *size > SWAPPER_BLOCK_SIZE)
 756                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 757                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
 758
 759         return dt_virt;
 760 }
 761
 762 void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 763 {
 764         void *dt_virt;
 765         int size;
 766
 767         dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
 768         if (!dt_virt)
 769                 return NULL;
 770
 771         memblock_reserve(dt_phys, size);
 772         return dt_virt;
 773 }
 774
 775 int __init arch_ioremap_pud_supported(void)
 776 {
 777         /* only 4k granule supports level 1 block mappings */
 778         return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
 779 }
 780
 781 int __init arch_ioremap_pmd_supported(void)
 782 {
 783         return 1;
 784 }
 785
 786 int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
 787 {
 788         BUG_ON(phys & ~PUD_MASK);
 789         set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 790         return 1;
 791 }
 792
 793 int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
 794 {
 795         BUG_ON(phys & ~PMD_MASK);
 796         set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 797         return 1;
 798 }
 799
 800 int pud_clear_huge(pud_t *pud)
 801 {
 802         if (!pud_sect(*pud))
 803                 return 0;
 804         pud_clear(pud);
 805         return 1;
 806 }
 807
 808 int pmd_clear_huge(pmd_t *pmd)
 809 {
 810         if (!pmd_sect(*pmd))
 811                 return 0;
 812         pmd_clear(pmd);
 813         return 1;
 814 }