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