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
  32 #include <asm/barrier.h>
  33 #include <asm/cputype.h>
  34 #include <asm/fixmap.h>
  35 #include <asm/kasan.h>
  36 #include <asm/kernel-pgtable.h>
  37 #include <asm/sections.h>
  38 #include <asm/setup.h>
  39 #include <asm/sizes.h>
  40 #include <asm/tlb.h>
  41 #include <asm/memblock.h>
  42 #include <asm/mmu_context.h>
  43 #include <asm/ptdump.h>
  44
  45 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
  46
  47 u64 kimage_voffset __ro_after_init;
  48 EXPORT_SYMBOL(kimage_voffset);
  49
  50 /*
  51  * Empty_zero_page is a special page that is used for zero-initialized data
  52  * and COW.
  53  */
  54 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
  55 EXPORT_SYMBOL(empty_zero_page);
  56
  57 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
  58 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
  59 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
  60
  61 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
  62                               unsigned long size, pgprot_t vma_prot)
  63 {
  64         if (!pfn_valid(pfn))
  65                 return pgprot_noncached(vma_prot);
  66         else if (file->f_flags & O_SYNC)
  67                 return pgprot_writecombine(vma_prot);
  68         return vma_prot;
  69 }
  70 EXPORT_SYMBOL(phys_mem_access_prot);
  71
  72 static phys_addr_t __init early_pgtable_alloc(void)
  73 {
  74         phys_addr_t phys;
  75         void *ptr;
  76
  77         phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
  78
  79         /*
  80          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
  81          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
  82          * any level of table.
  83          */
  84         ptr = pte_set_fixmap(phys);
  85
  86         memset(ptr, 0, PAGE_SIZE);
  87
  88         /*
  89          * Implicit barriers also ensure the zeroed page is visible to the page
  90          * table walker
  91          */
  92         pte_clear_fixmap();
  93
  94         return phys;
  95 }
  96
  97 static bool pgattr_change_is_safe(u64 old, u64 new)
  98 {
  99         /*
 100          * The following mapping attributes may be updated in live
 101          * kernel mappings without the need for break-before-make.
 102          */
 103         static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE;
 104
 105         return old  == 0 || new  == 0 || ((old ^ new) & ~mask) == 0;
 106 }
 107
 108 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 109                                   unsigned long end, unsigned long pfn,
 110                                   pgprot_t prot,
 111                                   phys_addr_t (*pgtable_alloc)(void),
 112                                   bool page_mappings_only)
 113 {
 114         pgprot_t __prot = prot;
 115         pte_t *pte;
 116
 117         BUG_ON(pmd_sect(*pmd));
 118         if (pmd_none(*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                 __pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
 124                 pte_clear_fixmap();
 125         }
 126         BUG_ON(pmd_bad(*pmd));
 127
 128         pte = pte_set_fixmap_offset(pmd, addr);
 129         do {
 130                 pte_t old_pte = *pte;
 131
 132                 /*
 133                  * Set the contiguous bit for the subsequent group of PTEs if
 134                  * its size and alignment are appropriate.
 135                  */
 136                 if (((addr | PFN_PHYS(pfn)) & ~CONT_PTE_MASK) == 0) {
 137                         if (end - addr >= CONT_PTE_SIZE && !page_mappings_only)
 138                                 __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
 139                         else
 140                                 __prot = prot;
 141                 }
 142
 143                 set_pte(pte, pfn_pte(pfn, __prot));
 144                 pfn++;
 145
 146                 /*
 147                  * After the PTE entry has been populated once, we
 148                  * only allow updates to the permission attributes.
 149                  */
 150                 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), pte_val(*pte)));
 151
 152         } while (pte++, addr += PAGE_SIZE, addr != end);
 153
 154         pte_clear_fixmap();
 155 }
 156
 157 static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 158                                   phys_addr_t phys, pgprot_t prot,
 159                                   phys_addr_t (*pgtable_alloc)(void),
 160                                   bool page_mappings_only)
 161 {
 162         pgprot_t __prot = prot;
 163         pmd_t *pmd;
 164         unsigned long next;
 165
 166         /*
 167          * Check for initial section mappings in the pgd/pud and remove them.
 168          */
 169         BUG_ON(pud_sect(*pud));
 170         if (pud_none(*pud)) {
 171                 phys_addr_t pmd_phys;
 172                 BUG_ON(!pgtable_alloc);
 173                 pmd_phys = pgtable_alloc();
 174                 pmd = pmd_set_fixmap(pmd_phys);
 175                 __pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
 176                 pmd_clear_fixmap();
 177         }
 178         BUG_ON(pud_bad(*pud));
 179
 180         pmd = pmd_set_fixmap_offset(pud, addr);
 181         do {
 182                 pmd_t old_pmd = *pmd;
 183
 184                 next = pmd_addr_end(addr, end);
 185
 186                 /* try section mapping first */
 187                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
 188                       !page_mappings_only) {
 189                         /*
 190                          * Set the contiguous bit for the subsequent group of
 191                          * PMDs if its size and alignment are appropriate.
 192                          */
 193                         if (((addr | phys) & ~CONT_PMD_MASK) == 0) {
 194                                 if (end - addr >= CONT_PMD_SIZE)
 195                                         __prot = __pgprot(pgprot_val(prot) |
 196                                                           PTE_CONT);
 197                                 else
 198                                         __prot = prot;
 199                         }
 200                         pmd_set_huge(pmd, phys, __prot);
 201
 202                         /*
 203                          * After the PMD entry has been populated once, we
 204                          * only allow updates to the permission attributes.
 205                          */
 206                         BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
 207                                                       pmd_val(*pmd)));
 208                 } else {
 209                         alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
 210                                        prot, pgtable_alloc,
 211                                        page_mappings_only);
 212
 213                         BUG_ON(pmd_val(old_pmd) != 0 &&
 214                                pmd_val(old_pmd) != pmd_val(*pmd));
 215                 }
 216                 phys += next - addr;
 217         } while (pmd++, addr = next, addr != end);
 218
 219         pmd_clear_fixmap();
 220 }
 221
 222 static inline bool use_1G_block(unsigned long addr, unsigned long next,
 223                         unsigned long phys)
 224 {
 225         if (PAGE_SHIFT != 12)
 226                 return false;
 227
 228         if (((addr | next | phys) & ~PUD_MASK) != 0)
 229                 return false;
 230
 231         return true;
 232 }
 233
 234 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 235                                   phys_addr_t phys, pgprot_t prot,
 236                                   phys_addr_t (*pgtable_alloc)(void),
 237                                   bool page_mappings_only)
 238 {
 239         pud_t *pud;
 240         unsigned long next;
 241
 242         if (pgd_none(*pgd)) {
 243                 phys_addr_t pud_phys;
 244                 BUG_ON(!pgtable_alloc);
 245                 pud_phys = pgtable_alloc();
 246                 __pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
 247         }
 248         BUG_ON(pgd_bad(*pgd));
 249
 250         pud = pud_set_fixmap_offset(pgd, addr);
 251         do {
 252                 pud_t old_pud = *pud;
 253
 254                 next = pud_addr_end(addr, end);
 255
 256                 /*
 257                  * For 4K granule only, attempt to put down a 1GB block
 258                  */
 259                 if (use_1G_block(addr, next, phys) && !page_mappings_only) {
 260                         pud_set_huge(pud, phys, prot);
 261
 262                         /*
 263                          * After the PUD entry has been populated once, we
 264                          * only allow updates to the permission attributes.
 265                          */
 266                         BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
 267                                                       pud_val(*pud)));
 268                 } else {
 269                         alloc_init_pmd(pud, addr, next, phys, prot,
 270                                        pgtable_alloc, page_mappings_only);
 271
 272                         BUG_ON(pud_val(old_pud) != 0 &&
 273                                pud_val(old_pud) != pud_val(*pud));
 274                 }
 275                 phys += next - addr;
 276         } while (pud++, addr = next, addr != end);
 277
 278         pud_clear_fixmap();
 279 }
 280
 281 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 282                                  unsigned long virt, phys_addr_t size,
 283                                  pgprot_t prot,
 284                                  phys_addr_t (*pgtable_alloc)(void),
 285                                  bool page_mappings_only)
 286 {
 287         unsigned long addr, length, end, next;
 288         pgd_t *pgd = pgd_offset_raw(pgdir, virt);
 289
 290         /*
 291          * If the virtual and physical address don't have the same offset
 292          * within a page, we cannot map the region as the caller expects.
 293          */
 294         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
 295                 return;
 296
 297         phys &= PAGE_MASK;
 298         addr = virt & PAGE_MASK;
 299         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
 300
 301         end = addr + length;
 302         do {
 303                 next = pgd_addr_end(addr, end);
 304                 alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc,
 305                                page_mappings_only);
 306                 phys += next - addr;
 307         } while (pgd++, addr = next, addr != end);
 308 }
 309
 310 static phys_addr_t pgd_pgtable_alloc(void)
 311 {
 312         void *ptr = (void *)__get_free_page(PGALLOC_GFP);
 313         if (!ptr || !pgtable_page_ctor(virt_to_page(ptr)))
 314                 BUG();
 315
 316         /* Ensure the zeroed page is visible to the page table walker */
 317         dsb(ishst);
 318         return __pa(ptr);
 319 }
 320
 321 /*
 322  * This function can only be used to modify existing table entries,
 323  * without allocating new levels of table. Note that this permits the
 324  * creation of new section or page entries.
 325  */
 326 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 327                                   phys_addr_t size, pgprot_t prot)
 328 {
 329         if (virt < VMALLOC_START) {
 330                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 331                         &phys, virt);
 332                 return;
 333         }
 334         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, false);
 335 }
 336
 337 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 338                                unsigned long virt, phys_addr_t size,
 339                                pgprot_t prot, bool page_mappings_only)
 340 {
 341         BUG_ON(mm == &init_mm);
 342
 343         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
 344                              pgd_pgtable_alloc, page_mappings_only);
 345 }
 346
 347 static void create_mapping_late(phys_addr_t phys, unsigned long virt,
 348                                   phys_addr_t size, pgprot_t prot)
 349 {
 350         if (virt < VMALLOC_START) {
 351                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 352                         &phys, virt);
 353                 return;
 354         }
 355
 356         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 357                              NULL, debug_pagealloc_enabled());
 358 }
 359
 360 static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
 361 {
 362         unsigned long kernel_start = __pa(_text);
 363         unsigned long kernel_end = __pa(__init_begin);
 364
 365         /*
 366          * Take care not to create a writable alias for the
 367          * read-only text and rodata sections of the kernel image.
 368          */
 369
 370         /* No overlap with the kernel text/rodata */
 371         if (end < kernel_start || start >= kernel_end) {
 372                 __create_pgd_mapping(pgd, start, __phys_to_virt(start),
 373                                      end - start, PAGE_KERNEL,
 374                                      early_pgtable_alloc,
 375                                      debug_pagealloc_enabled());
 376                 return;
 377         }
 378
 379         /*
 380          * This block overlaps the kernel text/rodata mappings.
 381          * Map the portion(s) which don't overlap.
 382          */
 383         if (start < kernel_start)
 384                 __create_pgd_mapping(pgd, start,
 385                                      __phys_to_virt(start),
 386                                      kernel_start - start, PAGE_KERNEL,
 387                                      early_pgtable_alloc,
 388                                      debug_pagealloc_enabled());
 389         if (kernel_end < end)
 390                 __create_pgd_mapping(pgd, kernel_end,
 391                                      __phys_to_virt(kernel_end),
 392                                      end - kernel_end, PAGE_KERNEL,
 393                                      early_pgtable_alloc,
 394                                      debug_pagealloc_enabled());
 395
 396         /*
 397          * Map the linear alias of the [_text, __init_begin) interval as
 398          * read-only/non-executable. This makes the contents of the
 399          * region accessible to subsystems such as hibernate, but
 400          * protects it from inadvertent modification or execution.
 401          */
 402         __create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
 403                              kernel_end - kernel_start, PAGE_KERNEL_RO,
 404                              early_pgtable_alloc, debug_pagealloc_enabled());
 405 }
 406
 407 static void __init map_mem(pgd_t *pgd)
 408 {
 409         struct memblock_region *reg;
 410
 411         /* map all the memory banks */
 412         for_each_memblock(memory, reg) {
 413                 phys_addr_t start = reg->base;
 414                 phys_addr_t end = start + reg->size;
 415
 416                 if (start >= end)
 417                         break;
 418                 if (memblock_is_nomap(reg))
 419                         continue;
 420
 421                 __map_memblock(pgd, start, end);
 422         }
 423 }
 424
 425 void mark_rodata_ro(void)
 426 {
 427         unsigned long section_size;
 428
 429         section_size = (unsigned long)_etext - (unsigned long)_text;
 430         create_mapping_late(__pa(_text), (unsigned long)_text,
 431                             section_size, PAGE_KERNEL_ROX);
 432         /*
 433          * mark .rodata as read only. Use __init_begin rather than __end_rodata
 434          * to cover NOTES and EXCEPTION_TABLE.
 435          */
 436         section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
 437         create_mapping_late(__pa(__start_rodata), (unsigned long)__start_rodata,
 438                             section_size, PAGE_KERNEL_RO);
 439
 440         /* flush the TLBs after updating live kernel mappings */
 441         flush_tlb_all();
 442
 443         debug_checkwx();
 444 }
 445
 446 static void __init map_kernel_segment(pgd_t *pgd, void *va_start, void *va_end,
 447                                       pgprot_t prot, struct vm_struct *vma)
 448 {
 449         phys_addr_t pa_start = __pa(va_start);
 450         unsigned long size = va_end - va_start;
 451
 452         BUG_ON(!PAGE_ALIGNED(pa_start));
 453         BUG_ON(!PAGE_ALIGNED(size));
 454
 455         __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
 456                              early_pgtable_alloc, debug_pagealloc_enabled());
 457
 458         vma->addr       = va_start;
 459         vma->phys_addr  = pa_start;
 460         vma->size       = size;
 461         vma->flags      = VM_MAP;
 462         vma->caller     = __builtin_return_address(0);
 463
 464         vm_area_add_early(vma);
 465 }
 466
 467 /*
 468  * Create fine-grained mappings for the kernel.
 469  */
 470 static void __init map_kernel(pgd_t *pgd)
 471 {
 472         static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
 473
 474         map_kernel_segment(pgd, _text, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
 475         map_kernel_segment(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata);
 476         map_kernel_segment(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
 477                            &vmlinux_init);
 478         map_kernel_segment(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
 479
 480         if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
 481                 /*
 482                  * The fixmap falls in a separate pgd to the kernel, and doesn't
 483                  * live in the carveout for the swapper_pg_dir. We can simply
 484                  * re-use the existing dir for the fixmap.
 485                  */
 486                 set_pgd(pgd_offset_raw(pgd, FIXADDR_START),
 487                         *pgd_offset_k(FIXADDR_START));
 488         } else if (CONFIG_PGTABLE_LEVELS > 3) {
 489                 /*
 490                  * The fixmap shares its top level pgd entry with the kernel
 491                  * mapping. This can really only occur when we are running
 492                  * with 16k/4 levels, so we can simply reuse the pud level
 493                  * entry instead.
 494                  */
 495                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 496                 set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
 497                         __pud(__pa(bm_pmd) | PUD_TYPE_TABLE));
 498                 pud_clear_fixmap();
 499         } else {
 500                 BUG();
 501         }
 502
 503         kasan_copy_shadow(pgd);
 504 }
 505
 506 /*
 507  * paging_init() sets up the page tables, initialises the zone memory
 508  * maps and sets up the zero page.
 509  */
 510 void __init paging_init(void)
 511 {
 512         phys_addr_t pgd_phys = early_pgtable_alloc();
 513         pgd_t *pgd = pgd_set_fixmap(pgd_phys);
 514
 515         map_kernel(pgd);
 516         map_mem(pgd);
 517
 518         /*
 519          * We want to reuse the original swapper_pg_dir so we don't have to
 520          * communicate the new address to non-coherent secondaries in
 521          * secondary_entry, and so cpu_switch_mm can generate the address with
 522          * adrp+add rather than a load from some global variable.
 523          *
 524          * To do this we need to go via a temporary pgd.
 525          */
 526         cpu_replace_ttbr1(__va(pgd_phys));
 527         memcpy(swapper_pg_dir, pgd, PAGE_SIZE);
 528         cpu_replace_ttbr1(swapper_pg_dir);
 529
 530         pgd_clear_fixmap();
 531         memblock_free(pgd_phys, PAGE_SIZE);
 532
 533         /*
 534          * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
 535          * allocated with it.
 536          */
 537         memblock_free(__pa(swapper_pg_dir) + PAGE_SIZE,
 538                       SWAPPER_DIR_SIZE - PAGE_SIZE);
 539 }
 540
 541 /*
 542  * Check whether a kernel address is valid (derived from arch/x86/).
 543  */
 544 int kern_addr_valid(unsigned long addr)
 545 {
 546         pgd_t *pgd;
 547         pud_t *pud;
 548         pmd_t *pmd;
 549         pte_t *pte;
 550
 551         if ((((long)addr) >> VA_BITS) != -1UL)
 552                 return 0;
 553
 554         pgd = pgd_offset_k(addr);
 555         if (pgd_none(*pgd))
 556                 return 0;
 557
 558         pud = pud_offset(pgd, addr);
 559         if (pud_none(*pud))
 560                 return 0;
 561
 562         if (pud_sect(*pud))
 563                 return pfn_valid(pud_pfn(*pud));
 564
 565         pmd = pmd_offset(pud, addr);
 566         if (pmd_none(*pmd))
 567                 return 0;
 568
 569         if (pmd_sect(*pmd))
 570                 return pfn_valid(pmd_pfn(*pmd));
 571
 572         pte = pte_offset_kernel(pmd, addr);
 573         if (pte_none(*pte))
 574                 return 0;
 575
 576         return pfn_valid(pte_pfn(*pte));
 577 }
 578 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 579 #if !ARM64_SWAPPER_USES_SECTION_MAPS
 580 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 581 {
 582         return vmemmap_populate_basepages(start, end, node);
 583 }
 584 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
 585 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 586 {
 587         unsigned long addr = start;
 588         unsigned long next;
 589         pgd_t *pgd;
 590         pud_t *pud;
 591         pmd_t *pmd;
 592
 593         do {
 594                 next = pmd_addr_end(addr, end);
 595
 596                 pgd = vmemmap_pgd_populate(addr, node);
 597                 if (!pgd)
 598                         return -ENOMEM;
 599
 600                 pud = vmemmap_pud_populate(pgd, addr, node);
 601                 if (!pud)
 602                         return -ENOMEM;
 603
 604                 pmd = pmd_offset(pud, addr);
 605                 if (pmd_none(*pmd)) {
 606                         void *p = NULL;
 607
 608                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
 609                         if (!p)
 610                                 return -ENOMEM;
 611
 612                         set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
 613                 } else
 614                         vmemmap_verify((pte_t *)pmd, node, addr, next);
 615         } while (addr = next, addr != end);
 616
 617         return 0;
 618 }
 619 #endif  /* CONFIG_ARM64_64K_PAGES */
 620 void vmemmap_free(unsigned long start, unsigned long end)
 621 {
 622 }
 623 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
 624
 625 static inline pud_t * fixmap_pud(unsigned long addr)
 626 {
 627         pgd_t *pgd = pgd_offset_k(addr);
 628
 629         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 630
 631         return pud_offset_kimg(pgd, addr);
 632 }
 633
 634 static inline pmd_t * fixmap_pmd(unsigned long addr)
 635 {
 636         pud_t *pud = fixmap_pud(addr);
 637
 638         BUG_ON(pud_none(*pud) || pud_bad(*pud));
 639
 640         return pmd_offset_kimg(pud, addr);
 641 }
 642
 643 static inline pte_t * fixmap_pte(unsigned long addr)
 644 {
 645         return &bm_pte[pte_index(addr)];
 646 }
 647
 648 void __init early_fixmap_init(void)
 649 {
 650         pgd_t *pgd;
 651         pud_t *pud;
 652         pmd_t *pmd;
 653         unsigned long addr = FIXADDR_START;
 654
 655         pgd = pgd_offset_k(addr);
 656         if (CONFIG_PGTABLE_LEVELS > 3 &&
 657             !(pgd_none(*pgd) || pgd_page_paddr(*pgd) == __pa(bm_pud))) {
 658                 /*
 659                  * We only end up here if the kernel mapping and the fixmap
 660                  * share the top level pgd entry, which should only happen on
 661                  * 16k/4 levels configurations.
 662                  */
 663                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 664                 pud = pud_offset_kimg(pgd, addr);
 665         } else {
 666                 pgd_populate(&init_mm, pgd, bm_pud);
 667                 pud = fixmap_pud(addr);
 668         }
 669         pud_populate(&init_mm, pud, bm_pmd);
 670         pmd = fixmap_pmd(addr);
 671         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 672
 673         /*
 674          * The boot-ioremap range spans multiple pmds, for which
 675          * we are not prepared:
 676          */
 677         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 678                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 679
 680         if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
 681              || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 682                 WARN_ON(1);
 683                 pr_warn("pmd %p != %p, %p\n",
 684                         pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
 685                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
 686                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 687                         fix_to_virt(FIX_BTMAP_BEGIN));
 688                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 689                         fix_to_virt(FIX_BTMAP_END));
 690
 691                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 692                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
 693         }
 694 }
 695
 696 void __set_fixmap(enum fixed_addresses idx,
 697                                phys_addr_t phys, pgprot_t flags)
 698 {
 699         unsigned long addr = __fix_to_virt(idx);
 700         pte_t *pte;
 701
 702         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 703
 704         pte = fixmap_pte(addr);
 705
 706         if (pgprot_val(flags)) {
 707                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 708         } else {
 709                 pte_clear(&init_mm, addr, pte);
 710                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 711         }
 712 }
 713
 714 void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 715 {
 716         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
 717         int offset;
 718         void *dt_virt;
 719
 720         /*
 721          * Check whether the physical FDT address is set and meets the minimum
 722          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
 723          * at least 8 bytes so that we can always access the magic and size
 724          * fields of the FDT header after mapping the first chunk, double check
 725          * here if that is indeed the case.
 726          */
 727         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 728         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
 729                 return NULL;
 730
 731         /*
 732          * Make sure that the FDT region can be mapped without the need to
 733          * allocate additional translation table pages, so that it is safe
 734          * to call create_mapping_noalloc() this early.
 735          *
 736          * On 64k pages, the FDT will be mapped using PTEs, so we need to
 737          * be in the same PMD as the rest of the fixmap.
 738          * On 4k pages, we'll use section mappings for the FDT so we only
 739          * have to be in the same PUD.
 740          */
 741         BUILD_BUG_ON(dt_virt_base % SZ_2M);
 742
 743         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
 744                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
 745
 746         offset = dt_phys % SWAPPER_BLOCK_SIZE;
 747         dt_virt = (void *)dt_virt_base + offset;
 748
 749         /* map the first chunk so we can read the size from the header */
 750         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
 751                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 752
 753         if (fdt_magic(dt_virt) != FDT_MAGIC)
 754                 return NULL;
 755
 756         *size = fdt_totalsize(dt_virt);
 757         if (*size > MAX_FDT_SIZE)
 758                 return NULL;
 759
 760         if (offset + *size > SWAPPER_BLOCK_SIZE)
 761                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 762                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
 763
 764         return dt_virt;
 765 }
 766
 767 void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 768 {
 769         void *dt_virt;
 770         int size;
 771
 772         dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
 773         if (!dt_virt)
 774                 return NULL;
 775
 776         memblock_reserve(dt_phys, size);
 777         return dt_virt;
 778 }
 779
 780 int __init arch_ioremap_pud_supported(void)
 781 {
 782         /* only 4k granule supports level 1 block mappings */
 783         return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
 784 }
 785
 786 int __init arch_ioremap_pmd_supported(void)
 787 {
 788         return 1;
 789 }
 790
 791 int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
 792 {
 793         BUG_ON(phys & ~PUD_MASK);
 794         set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 795         return 1;
 796 }
 797
 798 int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
 799 {
 800         BUG_ON(phys & ~PMD_MASK);
 801         set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 802         return 1;
 803 }
 804
 805 int pud_clear_huge(pud_t *pud)
 806 {
 807         if (!pud_sect(*pud))
 808                 return 0;
 809         pud_clear(pud);
 810         return 1;
 811 }
 812
 813 int pmd_clear_huge(pmd_t *pmd)
 814 {
 815         if (!pmd_sect(*pmd))
 816                 return 0;
 817         pmd_clear(pmd);
 818         return 1;
 819 }