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 u64 kimage_voffset __read_mostly;
  50 EXPORT_SYMBOL(kimage_voffset);
  51
  52 /*
  53  * Empty_zero_page is a special page that is used for zero-initialized data
  54  * and COW.
  55  */
  56 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
  57 EXPORT_SYMBOL(empty_zero_page);
  58
  59 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
  60 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
  61 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
  62
  63 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
  64                               unsigned long size, pgprot_t vma_prot)
  65 {
  66         if (!pfn_valid(pfn))
  67                 return pgprot_noncached(vma_prot);
  68         else if (file->f_flags & O_SYNC)
  69                 return pgprot_writecombine(vma_prot);
  70         return vma_prot;
  71 }
  72 EXPORT_SYMBOL(phys_mem_access_prot);
  73
  74 static phys_addr_t __init early_pgtable_alloc(void)
  75 {
  76         phys_addr_t phys;
  77         void *ptr;
  78
  79         phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
  80         BUG_ON(!phys);
  81
  82         /*
  83          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
  84          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
  85          * any level of table.
  86          */
  87         ptr = pte_set_fixmap(phys);
  88
  89         memset(ptr, 0, PAGE_SIZE);
  90
  91         /*
  92          * Implicit barriers also ensure the zeroed page is visible to the page
  93          * table walker
  94          */
  95         pte_clear_fixmap();
  96
  97         return phys;
  98 }
  99
 100 /*
 101  * remap a PMD into pages
 102  */
 103 static void split_pmd(pmd_t *pmd, pte_t *pte)
 104 {
 105         unsigned long pfn = pmd_pfn(*pmd);
 106         int i = 0;
 107
 108         do {
 109                 /*
 110                  * Need to have the least restrictive permissions available
 111                  * permissions will be fixed up later
 112                  */
 113                 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 114                 pfn++;
 115         } while (pte++, i++, i < PTRS_PER_PTE);
 116 }
 117
 118 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 119                                   unsigned long end, unsigned long pfn,
 120                                   pgprot_t prot,
 121                                   phys_addr_t (*pgtable_alloc)(void))
 122 {
 123         pte_t *pte;
 124
 125         if (pmd_none(*pmd) || pmd_sect(*pmd)) {
 126                 phys_addr_t pte_phys;
 127                 BUG_ON(!pgtable_alloc);
 128                 pte_phys = pgtable_alloc();
 129                 pte = pte_set_fixmap(pte_phys);
 130                 if (pmd_sect(*pmd))
 131                         split_pmd(pmd, pte);
 132                 __pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
 133                 flush_tlb_all();
 134                 pte_clear_fixmap();
 135         }
 136         BUG_ON(pmd_bad(*pmd));
 137
 138         pte = pte_set_fixmap_offset(pmd, addr);
 139         do {
 140                 set_pte(pte, pfn_pte(pfn, prot));
 141                 pfn++;
 142         } while (pte++, addr += PAGE_SIZE, addr != end);
 143
 144         pte_clear_fixmap();
 145 }
 146
 147 static void split_pud(pud_t *old_pud, pmd_t *pmd)
 148 {
 149         unsigned long addr = pud_pfn(*old_pud) << PAGE_SHIFT;
 150         pgprot_t prot = __pgprot(pud_val(*old_pud) ^ addr);
 151         int i = 0;
 152
 153         do {
 154                 set_pmd(pmd, __pmd(addr | pgprot_val(prot)));
 155                 addr += PMD_SIZE;
 156         } while (pmd++, i++, i < PTRS_PER_PMD);
 157 }
 158
 159 #ifdef CONFIG_DEBUG_PAGEALLOC
 160 static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
 161 {
 162
 163         /*
 164          * If debug_page_alloc is enabled we must map the linear map
 165          * using pages. However, other mappings created by
 166          * create_mapping_noalloc must use sections in some cases. Allow
 167          * sections to be used in those cases, where no pgtable_alloc
 168          * function is provided.
 169          */
 170         return !pgtable_alloc || !debug_pagealloc_enabled();
 171 }
 172 #else
 173 static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
 174 {
 175         return true;
 176 }
 177 #endif
 178
 179 static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 180                                   phys_addr_t phys, pgprot_t prot,
 181                                   phys_addr_t (*pgtable_alloc)(void))
 182 {
 183         pmd_t *pmd;
 184         unsigned long next;
 185
 186         /*
 187          * Check for initial section mappings in the pgd/pud and remove them.
 188          */
 189         if (pud_none(*pud) || pud_sect(*pud)) {
 190                 phys_addr_t pmd_phys;
 191                 BUG_ON(!pgtable_alloc);
 192                 pmd_phys = pgtable_alloc();
 193                 pmd = pmd_set_fixmap(pmd_phys);
 194                 if (pud_sect(*pud)) {
 195                         /*
 196                          * need to have the 1G of mappings continue to be
 197                          * present
 198                          */
 199                         split_pud(pud, pmd);
 200                 }
 201                 __pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
 202                 flush_tlb_all();
 203                 pmd_clear_fixmap();
 204         }
 205         BUG_ON(pud_bad(*pud));
 206
 207         pmd = pmd_set_fixmap_offset(pud, addr);
 208         do {
 209                 next = pmd_addr_end(addr, end);
 210                 /* try section mapping first */
 211                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
 212                       block_mappings_allowed(pgtable_alloc)) {
 213                         pmd_t old_pmd =*pmd;
 214                         set_pmd(pmd, __pmd(phys |
 215                                            pgprot_val(mk_sect_prot(prot))));
 216                         /*
 217                          * Check for previous table entries created during
 218                          * boot (__create_page_tables) and flush them.
 219                          */
 220                         if (!pmd_none(old_pmd)) {
 221                                 flush_tlb_all();
 222                                 if (pmd_table(old_pmd)) {
 223                                         phys_addr_t table = pmd_page_paddr(old_pmd);
 224                                         if (!WARN_ON_ONCE(slab_is_available()))
 225                                                 memblock_free(table, PAGE_SIZE);
 226                                 }
 227                         }
 228                 } else {
 229                         alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
 230                                        prot, pgtable_alloc);
 231                 }
 232                 phys += next - addr;
 233         } while (pmd++, addr = next, addr != end);
 234
 235         pmd_clear_fixmap();
 236 }
 237
 238 static inline bool use_1G_block(unsigned long addr, unsigned long next,
 239                         unsigned long phys)
 240 {
 241         if (PAGE_SHIFT != 12)
 242                 return false;
 243
 244         if (((addr | next | phys) & ~PUD_MASK) != 0)
 245                 return false;
 246
 247         return true;
 248 }
 249
 250 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 251                                   phys_addr_t phys, pgprot_t prot,
 252                                   phys_addr_t (*pgtable_alloc)(void))
 253 {
 254         pud_t *pud;
 255         unsigned long next;
 256
 257         if (pgd_none(*pgd)) {
 258                 phys_addr_t pud_phys;
 259                 BUG_ON(!pgtable_alloc);
 260                 pud_phys = pgtable_alloc();
 261                 __pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
 262         }
 263         BUG_ON(pgd_bad(*pgd));
 264
 265         pud = pud_set_fixmap_offset(pgd, addr);
 266         do {
 267                 next = pud_addr_end(addr, end);
 268
 269                 /*
 270                  * For 4K granule only, attempt to put down a 1GB block
 271                  */
 272                 if (use_1G_block(addr, next, phys) &&
 273                     block_mappings_allowed(pgtable_alloc)) {
 274                         pud_t old_pud = *pud;
 275                         set_pud(pud, __pud(phys |
 276                                            pgprot_val(mk_sect_prot(prot))));
 277
 278                         /*
 279                          * If we have an old value for a pud, it will
 280                          * be pointing to a pmd table that we no longer
 281                          * need (from swapper_pg_dir).
 282                          *
 283                          * Look up the old pmd table and free it.
 284                          */
 285                         if (!pud_none(old_pud)) {
 286                                 flush_tlb_all();
 287                                 if (pud_table(old_pud)) {
 288                                         phys_addr_t table = pud_page_paddr(old_pud);
 289                                         if (!WARN_ON_ONCE(slab_is_available()))
 290                                                 memblock_free(table, PAGE_SIZE);
 291                                 }
 292                         }
 293                 } else {
 294                         alloc_init_pmd(pud, addr, next, phys, prot,
 295                                        pgtable_alloc);
 296                 }
 297                 phys += next - addr;
 298         } while (pud++, addr = next, addr != end);
 299
 300         pud_clear_fixmap();
 301 }
 302
 303 /*
 304  * Create the page directory entries and any necessary page tables for the
 305  * mapping specified by 'md'.
 306  */
 307 static void init_pgd(pgd_t *pgd, phys_addr_t phys, unsigned long virt,
 308                                     phys_addr_t size, pgprot_t prot,
 309                                     phys_addr_t (*pgtable_alloc)(void))
 310 {
 311         unsigned long addr, length, end, next;
 312
 313         /*
 314          * If the virtual and physical address don't have the same offset
 315          * within a page, we cannot map the region as the caller expects.
 316          */
 317         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
 318                 return;
 319
 320         phys &= PAGE_MASK;
 321         addr = virt & PAGE_MASK;
 322         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
 323
 324         end = addr + length;
 325         do {
 326                 next = pgd_addr_end(addr, end);
 327                 alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc);
 328                 phys += next - addr;
 329         } while (pgd++, addr = next, addr != end);
 330 }
 331
 332 static phys_addr_t late_pgtable_alloc(void)
 333 {
 334         void *ptr = (void *)__get_free_page(PGALLOC_GFP);
 335         BUG_ON(!ptr);
 336
 337         /* Ensure the zeroed page is visible to the page table walker */
 338         dsb(ishst);
 339         return __pa(ptr);
 340 }
 341
 342 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 343                                  unsigned long virt, phys_addr_t size,
 344                                  pgprot_t prot,
 345                                  phys_addr_t (*alloc)(void))
 346 {
 347         init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc);
 348 }
 349
 350 /*
 351  * This function can only be used to modify existing table entries,
 352  * without allocating new levels of table. Note that this permits the
 353  * creation of new section or page entries.
 354  */
 355 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 356                                   phys_addr_t size, pgprot_t prot)
 357 {
 358         if (virt < VMALLOC_START) {
 359                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 360                         &phys, virt);
 361                 return;
 362         }
 363         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 364                              NULL);
 365 }
 366
 367 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 368                                unsigned long virt, phys_addr_t size,
 369                                pgprot_t prot)
 370 {
 371         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
 372                              late_pgtable_alloc);
 373 }
 374
 375 static void create_mapping_late(phys_addr_t phys, unsigned long virt,
 376                                   phys_addr_t size, pgprot_t prot)
 377 {
 378         if (virt < VMALLOC_START) {
 379                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 380                         &phys, virt);
 381                 return;
 382         }
 383
 384         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 385                              late_pgtable_alloc);
 386 }
 387
 388 static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
 389 {
 390         unsigned long kernel_start = __pa(_stext);
 391         unsigned long kernel_end = __pa(_etext);
 392
 393         /*
 394          * Take care not to create a writable alias for the
 395          * read-only text and rodata sections of the kernel image.
 396          */
 397
 398         /* No overlap with the kernel text */
 399         if (end < kernel_start || start >= kernel_end) {
 400                 __create_pgd_mapping(pgd, start, __phys_to_virt(start),
 401                                      end - start, PAGE_KERNEL,
 402                                      early_pgtable_alloc);
 403                 return;
 404         }
 405
 406         /*
 407          * This block overlaps the kernel text mapping.
 408          * Map the portion(s) which don't overlap.
 409          */
 410         if (start < kernel_start)
 411                 __create_pgd_mapping(pgd, start,
 412                                      __phys_to_virt(start),
 413                                      kernel_start - start, PAGE_KERNEL,
 414                                      early_pgtable_alloc);
 415         if (kernel_end < end)
 416                 __create_pgd_mapping(pgd, kernel_end,
 417                                      __phys_to_virt(kernel_end),
 418                                      end - kernel_end, PAGE_KERNEL,
 419                                      early_pgtable_alloc);
 420
 421         /*
 422          * Map the linear alias of the [_stext, _etext) interval as
 423          * read-only/non-executable. This makes the contents of the
 424          * region accessible to subsystems such as hibernate, but
 425          * protects it from inadvertent modification or execution.
 426          */
 427         __create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
 428                              kernel_end - kernel_start, PAGE_KERNEL_RO,
 429                              early_pgtable_alloc);
 430 }
 431
 432 static void __init map_mem(pgd_t *pgd)
 433 {
 434         struct memblock_region *reg;
 435
 436         /* map all the memory banks */
 437         for_each_memblock(memory, reg) {
 438                 phys_addr_t start = reg->base;
 439                 phys_addr_t end = start + reg->size;
 440
 441                 if (start >= end)
 442                         break;
 443                 if (memblock_is_nomap(reg))
 444                         continue;
 445
 446                 __map_memblock(pgd, start, end);
 447         }
 448 }
 449
 450 void mark_rodata_ro(void)
 451 {
 452         if (!IS_ENABLED(CONFIG_DEBUG_RODATA))
 453                 return;
 454
 455         create_mapping_late(__pa(_stext), (unsigned long)_stext,
 456                                 (unsigned long)_etext - (unsigned long)_stext,
 457                                 PAGE_KERNEL_ROX);
 458 }
 459
 460 void fixup_init(void)
 461 {
 462         /*
 463          * Unmap the __init region but leave the VM area in place. This
 464          * prevents the region from being reused for kernel modules, which
 465          * is not supported by kallsyms.
 466          */
 467         unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
 468 }
 469
 470 static void __init map_kernel_chunk(pgd_t *pgd, void *va_start, void *va_end,
 471                                     pgprot_t prot, struct vm_struct *vma)
 472 {
 473         phys_addr_t pa_start = __pa(va_start);
 474         unsigned long size = va_end - va_start;
 475
 476         BUG_ON(!PAGE_ALIGNED(pa_start));
 477         BUG_ON(!PAGE_ALIGNED(size));
 478
 479         __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
 480                              early_pgtable_alloc);
 481
 482         vma->addr       = va_start;
 483         vma->phys_addr  = pa_start;
 484         vma->size       = size;
 485         vma->flags      = VM_MAP;
 486         vma->caller     = __builtin_return_address(0);
 487
 488         vm_area_add_early(vma);
 489 }
 490
 491 /*
 492  * Create fine-grained mappings for the kernel.
 493  */
 494 static void __init map_kernel(pgd_t *pgd)
 495 {
 496         static struct vm_struct vmlinux_text, vmlinux_init, vmlinux_data;
 497
 498         map_kernel_chunk(pgd, _stext, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
 499         map_kernel_chunk(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
 500                          &vmlinux_init);
 501         map_kernel_chunk(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
 502
 503         if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
 504                 /*
 505                  * The fixmap falls in a separate pgd to the kernel, and doesn't
 506                  * live in the carveout for the swapper_pg_dir. We can simply
 507                  * re-use the existing dir for the fixmap.
 508                  */
 509                 set_pgd(pgd_offset_raw(pgd, FIXADDR_START),
 510                         *pgd_offset_k(FIXADDR_START));
 511         } else if (CONFIG_PGTABLE_LEVELS > 3) {
 512                 /*
 513                  * The fixmap shares its top level pgd entry with the kernel
 514                  * mapping. This can really only occur when we are running
 515                  * with 16k/4 levels, so we can simply reuse the pud level
 516                  * entry instead.
 517                  */
 518                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 519                 set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
 520                         __pud(__pa(bm_pmd) | PUD_TYPE_TABLE));
 521                 pud_clear_fixmap();
 522         } else {
 523                 BUG();
 524         }
 525
 526         kasan_copy_shadow(pgd);
 527 }
 528
 529 /*
 530  * paging_init() sets up the page tables, initialises the zone memory
 531  * maps and sets up the zero page.
 532  */
 533 void __init paging_init(void)
 534 {
 535         phys_addr_t pgd_phys = early_pgtable_alloc();
 536         pgd_t *pgd = pgd_set_fixmap(pgd_phys);
 537
 538         map_kernel(pgd);
 539         map_mem(pgd);
 540
 541         /*
 542          * We want to reuse the original swapper_pg_dir so we don't have to
 543          * communicate the new address to non-coherent secondaries in
 544          * secondary_entry, and so cpu_switch_mm can generate the address with
 545          * adrp+add rather than a load from some global variable.
 546          *
 547          * To do this we need to go via a temporary pgd.
 548          */
 549         cpu_replace_ttbr1(__va(pgd_phys));
 550         memcpy(swapper_pg_dir, pgd, PAGE_SIZE);
 551         cpu_replace_ttbr1(swapper_pg_dir);
 552
 553         pgd_clear_fixmap();
 554         memblock_free(pgd_phys, PAGE_SIZE);
 555
 556         /*
 557          * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
 558          * allocated with it.
 559          */
 560         memblock_free(__pa(swapper_pg_dir) + PAGE_SIZE,
 561                       SWAPPER_DIR_SIZE - PAGE_SIZE);
 562
 563         bootmem_init();
 564 }
 565
 566 /*
 567  * Check whether a kernel address is valid (derived from arch/x86/).
 568  */
 569 int kern_addr_valid(unsigned long addr)
 570 {
 571         pgd_t *pgd;
 572         pud_t *pud;
 573         pmd_t *pmd;
 574         pte_t *pte;
 575
 576         if ((((long)addr) >> VA_BITS) != -1UL)
 577                 return 0;
 578
 579         pgd = pgd_offset_k(addr);
 580         if (pgd_none(*pgd))
 581                 return 0;
 582
 583         pud = pud_offset(pgd, addr);
 584         if (pud_none(*pud))
 585                 return 0;
 586
 587         if (pud_sect(*pud))
 588                 return pfn_valid(pud_pfn(*pud));
 589
 590         pmd = pmd_offset(pud, addr);
 591         if (pmd_none(*pmd))
 592                 return 0;
 593
 594         if (pmd_sect(*pmd))
 595                 return pfn_valid(pmd_pfn(*pmd));
 596
 597         pte = pte_offset_kernel(pmd, addr);
 598         if (pte_none(*pte))
 599                 return 0;
 600
 601         return pfn_valid(pte_pfn(*pte));
 602 }
 603 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 604 #if !ARM64_SWAPPER_USES_SECTION_MAPS
 605 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 606 {
 607         return vmemmap_populate_basepages(start, end, node);
 608 }
 609 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
 610 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 611 {
 612         unsigned long addr = start;
 613         unsigned long next;
 614         pgd_t *pgd;
 615         pud_t *pud;
 616         pmd_t *pmd;
 617
 618         do {
 619                 next = pmd_addr_end(addr, end);
 620
 621                 pgd = vmemmap_pgd_populate(addr, node);
 622                 if (!pgd)
 623                         return -ENOMEM;
 624
 625                 pud = vmemmap_pud_populate(pgd, addr, node);
 626                 if (!pud)
 627                         return -ENOMEM;
 628
 629                 pmd = pmd_offset(pud, addr);
 630                 if (pmd_none(*pmd)) {
 631                         void *p = NULL;
 632
 633                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
 634                         if (!p)
 635                                 return -ENOMEM;
 636
 637                         set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
 638                 } else
 639                         vmemmap_verify((pte_t *)pmd, node, addr, next);
 640         } while (addr = next, addr != end);
 641
 642         return 0;
 643 }
 644 #endif  /* CONFIG_ARM64_64K_PAGES */
 645 void vmemmap_free(unsigned long start, unsigned long end)
 646 {
 647 }
 648 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
 649
 650 static inline pud_t * fixmap_pud(unsigned long addr)
 651 {
 652         pgd_t *pgd = pgd_offset_k(addr);
 653
 654         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 655
 656         return pud_offset_kimg(pgd, addr);
 657 }
 658
 659 static inline pmd_t * fixmap_pmd(unsigned long addr)
 660 {
 661         pud_t *pud = fixmap_pud(addr);
 662
 663         BUG_ON(pud_none(*pud) || pud_bad(*pud));
 664
 665         return pmd_offset_kimg(pud, addr);
 666 }
 667
 668 static inline pte_t * fixmap_pte(unsigned long addr)
 669 {
 670         return &bm_pte[pte_index(addr)];
 671 }
 672
 673 void __init early_fixmap_init(void)
 674 {
 675         pgd_t *pgd;
 676         pud_t *pud;
 677         pmd_t *pmd;
 678         unsigned long addr = FIXADDR_START;
 679
 680         pgd = pgd_offset_k(addr);
 681         if (CONFIG_PGTABLE_LEVELS > 3 && !pgd_none(*pgd)) {
 682                 /*
 683                  * We only end up here if the kernel mapping and the fixmap
 684                  * share the top level pgd entry, which should only happen on
 685                  * 16k/4 levels configurations.
 686                  */
 687                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 688                 pud = pud_offset_kimg(pgd, addr);
 689         } else {
 690                 pgd_populate(&init_mm, pgd, bm_pud);
 691                 pud = fixmap_pud(addr);
 692         }
 693         pud_populate(&init_mm, pud, bm_pmd);
 694         pmd = fixmap_pmd(addr);
 695         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 696
 697         /*
 698          * The boot-ioremap range spans multiple pmds, for which
 699          * we are not prepared:
 700          */
 701         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 702                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 703
 704         if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
 705              || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 706                 WARN_ON(1);
 707                 pr_warn("pmd %p != %p, %p\n",
 708                         pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
 709                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
 710                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 711                         fix_to_virt(FIX_BTMAP_BEGIN));
 712                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 713                         fix_to_virt(FIX_BTMAP_END));
 714
 715                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 716                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
 717         }
 718 }
 719
 720 void __set_fixmap(enum fixed_addresses idx,
 721                                phys_addr_t phys, pgprot_t flags)
 722 {
 723         unsigned long addr = __fix_to_virt(idx);
 724         pte_t *pte;
 725
 726         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 727
 728         pte = fixmap_pte(addr);
 729
 730         if (pgprot_val(flags)) {
 731                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 732         } else {
 733                 pte_clear(&init_mm, addr, pte);
 734                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 735         }
 736 }
 737
 738 void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 739 {
 740         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
 741         pgprot_t prot = PAGE_KERNEL_RO;
 742         int size, offset;
 743         void *dt_virt;
 744
 745         /*
 746          * Check whether the physical FDT address is set and meets the minimum
 747          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
 748          * at least 8 bytes so that we can always access the size field of the
 749          * FDT header after mapping the first chunk, double check here if that
 750          * is indeed the case.
 751          */
 752         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 753         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
 754                 return NULL;
 755
 756         /*
 757          * Make sure that the FDT region can be mapped without the need to
 758          * allocate additional translation table pages, so that it is safe
 759          * to call create_mapping_noalloc() this early.
 760          *
 761          * On 64k pages, the FDT will be mapped using PTEs, so we need to
 762          * be in the same PMD as the rest of the fixmap.
 763          * On 4k pages, we'll use section mappings for the FDT so we only
 764          * have to be in the same PUD.
 765          */
 766         BUILD_BUG_ON(dt_virt_base % SZ_2M);
 767
 768         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
 769                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
 770
 771         offset = dt_phys % SWAPPER_BLOCK_SIZE;
 772         dt_virt = (void *)dt_virt_base + offset;
 773
 774         /* map the first chunk so we can read the size from the header */
 775         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
 776                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 777
 778         if (fdt_check_header(dt_virt) != 0)
 779                 return NULL;
 780
 781         size = fdt_totalsize(dt_virt);
 782         if (size > MAX_FDT_SIZE)
 783                 return NULL;
 784
 785         if (offset + size > SWAPPER_BLOCK_SIZE)
 786                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 787                                round_up(offset + size, SWAPPER_BLOCK_SIZE), prot);
 788
 789         memblock_reserve(dt_phys, size);
 790
 791         return dt_virt;
 792 }
 793
 794 int __init arch_ioremap_pud_supported(void)
 795 {
 796         /* only 4k granule supports level 1 block mappings */
 797         return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
 798 }
 799
 800 int __init arch_ioremap_pmd_supported(void)
 801 {
 802         return 1;
 803 }
 804
 805 int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
 806 {
 807         BUG_ON(phys & ~PUD_MASK);
 808         set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 809         return 1;
 810 }
 811
 812 int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
 813 {
 814         BUG_ON(phys & ~PMD_MASK);
 815         set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 816         return 1;
 817 }
 818
 819 int pud_clear_huge(pud_t *pud)
 820 {
 821         if (!pud_sect(*pud))
 822                 return 0;
 823         pud_clear(pud);
 824         return 1;
 825 }
 826
 827 int pmd_clear_huge(pmd_t *pmd)
 828 {
 829         if (!pmd_sect(*pmd))
 830                 return 0;
 831         pmd_clear(pmd);
 832         return 1;
 833 }