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                         pmd_set_huge(pmd, phys, prot);
 215                         /*
 216                          * Check for previous table entries created during
 217                          * boot (__create_page_tables) and flush them.
 218                          */
 219                         if (!pmd_none(old_pmd)) {
 220                                 flush_tlb_all();
 221                                 if (pmd_table(old_pmd)) {
 222                                         phys_addr_t table = pmd_page_paddr(old_pmd);
 223                                         if (!WARN_ON_ONCE(slab_is_available()))
 224                                                 memblock_free(table, PAGE_SIZE);
 225                                 }
 226                         }
 227                 } else {
 228                         alloc_init_pte(pmd, addr, next, __phys_to_pfn(phys),
 229                                        prot, pgtable_alloc);
 230                 }
 231                 phys += next - addr;
 232         } while (pmd++, addr = next, addr != end);
 233
 234         pmd_clear_fixmap();
 235 }
 236
 237 static inline bool use_1G_block(unsigned long addr, unsigned long next,
 238                         unsigned long phys)
 239 {
 240         if (PAGE_SHIFT != 12)
 241                 return false;
 242
 243         if (((addr | next | phys) & ~PUD_MASK) != 0)
 244                 return false;
 245
 246         return true;
 247 }
 248
 249 static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 250                                   phys_addr_t phys, pgprot_t prot,
 251                                   phys_addr_t (*pgtable_alloc)(void))
 252 {
 253         pud_t *pud;
 254         unsigned long next;
 255
 256         if (pgd_none(*pgd)) {
 257                 phys_addr_t pud_phys;
 258                 BUG_ON(!pgtable_alloc);
 259                 pud_phys = pgtable_alloc();
 260                 __pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
 261         }
 262         BUG_ON(pgd_bad(*pgd));
 263
 264         pud = pud_set_fixmap_offset(pgd, addr);
 265         do {
 266                 next = pud_addr_end(addr, end);
 267
 268                 /*
 269                  * For 4K granule only, attempt to put down a 1GB block
 270                  */
 271                 if (use_1G_block(addr, next, phys) &&
 272                     block_mappings_allowed(pgtable_alloc)) {
 273                         pud_t old_pud = *pud;
 274                         pud_set_huge(pud, phys, prot);
 275
 276                         /*
 277                          * If we have an old value for a pud, it will
 278                          * be pointing to a pmd table that we no longer
 279                          * need (from swapper_pg_dir).
 280                          *
 281                          * Look up the old pmd table and free it.
 282                          */
 283                         if (!pud_none(old_pud)) {
 284                                 flush_tlb_all();
 285                                 if (pud_table(old_pud)) {
 286                                         phys_addr_t table = pud_page_paddr(old_pud);
 287                                         if (!WARN_ON_ONCE(slab_is_available()))
 288                                                 memblock_free(table, PAGE_SIZE);
 289                                 }
 290                         }
 291                 } else {
 292                         alloc_init_pmd(pud, addr, next, phys, prot,
 293                                        pgtable_alloc);
 294                 }
 295                 phys += next - addr;
 296         } while (pud++, addr = next, addr != end);
 297
 298         pud_clear_fixmap();
 299 }
 300
 301 /*
 302  * Create the page directory entries and any necessary page tables for the
 303  * mapping specified by 'md'.
 304  */
 305 static void init_pgd(pgd_t *pgd, phys_addr_t phys, unsigned long virt,
 306                                     phys_addr_t size, pgprot_t prot,
 307                                     phys_addr_t (*pgtable_alloc)(void))
 308 {
 309         unsigned long addr, length, end, next;
 310
 311         /*
 312          * If the virtual and physical address don't have the same offset
 313          * within a page, we cannot map the region as the caller expects.
 314          */
 315         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
 316                 return;
 317
 318         phys &= PAGE_MASK;
 319         addr = virt & PAGE_MASK;
 320         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
 321
 322         end = addr + length;
 323         do {
 324                 next = pgd_addr_end(addr, end);
 325                 alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc);
 326                 phys += next - addr;
 327         } while (pgd++, addr = next, addr != end);
 328 }
 329
 330 static phys_addr_t late_pgtable_alloc(void)
 331 {
 332         void *ptr = (void *)__get_free_page(PGALLOC_GFP);
 333         BUG_ON(!ptr);
 334
 335         /* Ensure the zeroed page is visible to the page table walker */
 336         dsb(ishst);
 337         return __pa(ptr);
 338 }
 339
 340 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 341                                  unsigned long virt, phys_addr_t size,
 342                                  pgprot_t prot,
 343                                  phys_addr_t (*alloc)(void))
 344 {
 345         init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc);
 346 }
 347
 348 /*
 349  * This function can only be used to modify existing table entries,
 350  * without allocating new levels of table. Note that this permits the
 351  * creation of new section or page entries.
 352  */
 353 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 354                                   phys_addr_t size, pgprot_t prot)
 355 {
 356         if (virt < VMALLOC_START) {
 357                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 358                         &phys, virt);
 359                 return;
 360         }
 361         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 362                              NULL);
 363 }
 364
 365 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 366                                unsigned long virt, phys_addr_t size,
 367                                pgprot_t prot)
 368 {
 369         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
 370                              late_pgtable_alloc);
 371 }
 372
 373 static void create_mapping_late(phys_addr_t phys, unsigned long virt,
 374                                   phys_addr_t size, pgprot_t prot)
 375 {
 376         if (virt < VMALLOC_START) {
 377                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 378                         &phys, virt);
 379                 return;
 380         }
 381
 382         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 383                              late_pgtable_alloc);
 384 }
 385
 386 static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
 387 {
 388         unsigned long kernel_start = __pa(_stext);
 389         unsigned long kernel_end = __pa(_etext);
 390
 391         /*
 392          * Take care not to create a writable alias for the
 393          * read-only text and rodata sections of the kernel image.
 394          */
 395
 396         /* No overlap with the kernel text */
 397         if (end < kernel_start || start >= kernel_end) {
 398                 __create_pgd_mapping(pgd, start, __phys_to_virt(start),
 399                                      end - start, PAGE_KERNEL,
 400                                      early_pgtable_alloc);
 401                 return;
 402         }
 403
 404         /*
 405          * This block overlaps the kernel text mapping.
 406          * Map the portion(s) which don't overlap.
 407          */
 408         if (start < kernel_start)
 409                 __create_pgd_mapping(pgd, start,
 410                                      __phys_to_virt(start),
 411                                      kernel_start - start, PAGE_KERNEL,
 412                                      early_pgtable_alloc);
 413         if (kernel_end < end)
 414                 __create_pgd_mapping(pgd, kernel_end,
 415                                      __phys_to_virt(kernel_end),
 416                                      end - kernel_end, PAGE_KERNEL,
 417                                      early_pgtable_alloc);
 418
 419         /*
 420          * Map the linear alias of the [_stext, _etext) interval as
 421          * read-only/non-executable. This makes the contents of the
 422          * region accessible to subsystems such as hibernate, but
 423          * protects it from inadvertent modification or execution.
 424          */
 425         __create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
 426                              kernel_end - kernel_start, PAGE_KERNEL_RO,
 427                              early_pgtable_alloc);
 428 }
 429
 430 static void __init map_mem(pgd_t *pgd)
 431 {
 432         struct memblock_region *reg;
 433
 434         /* map all the memory banks */
 435         for_each_memblock(memory, reg) {
 436                 phys_addr_t start = reg->base;
 437                 phys_addr_t end = start + reg->size;
 438
 439                 if (start >= end)
 440                         break;
 441
 442                 __map_memblock(pgd, start, end);
 443         }
 444 }
 445
 446 void mark_rodata_ro(void)
 447 {
 448         if (!IS_ENABLED(CONFIG_DEBUG_RODATA))
 449                 return;
 450
 451         create_mapping_late(__pa(_stext), (unsigned long)_stext,
 452                                 (unsigned long)_etext - (unsigned long)_stext,
 453                                 PAGE_KERNEL_ROX);
 454 }
 455
 456 void fixup_init(void)
 457 {
 458         /*
 459          * Unmap the __init region but leave the VM area in place. This
 460          * prevents the region from being reused for kernel modules, which
 461          * is not supported by kallsyms.
 462          */
 463         unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
 464 }
 465
 466 static void __init map_kernel_chunk(pgd_t *pgd, void *va_start, void *va_end,
 467                                     pgprot_t prot, struct vm_struct *vma)
 468 {
 469         phys_addr_t pa_start = __pa(va_start);
 470         unsigned long size = va_end - va_start;
 471
 472         BUG_ON(!PAGE_ALIGNED(pa_start));
 473         BUG_ON(!PAGE_ALIGNED(size));
 474
 475         __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
 476                              early_pgtable_alloc);
 477
 478         vma->addr       = va_start;
 479         vma->phys_addr  = pa_start;
 480         vma->size       = size;
 481         vma->flags      = VM_MAP;
 482         vma->caller     = __builtin_return_address(0);
 483
 484         vm_area_add_early(vma);
 485 }
 486
 487 /*
 488  * Create fine-grained mappings for the kernel.
 489  */
 490 static void __init map_kernel(pgd_t *pgd)
 491 {
 492         static struct vm_struct vmlinux_text, vmlinux_init, vmlinux_data;
 493
 494         map_kernel_chunk(pgd, _stext, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
 495         map_kernel_chunk(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
 496                          &vmlinux_init);
 497         map_kernel_chunk(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
 498
 499         if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
 500                 /*
 501                  * The fixmap falls in a separate pgd to the kernel, and doesn't
 502                  * live in the carveout for the swapper_pg_dir. We can simply
 503                  * re-use the existing dir for the fixmap.
 504                  */
 505                 set_pgd(pgd_offset_raw(pgd, FIXADDR_START),
 506                         *pgd_offset_k(FIXADDR_START));
 507         } else if (CONFIG_PGTABLE_LEVELS > 3) {
 508                 /*
 509                  * The fixmap shares its top level pgd entry with the kernel
 510                  * mapping. This can really only occur when we are running
 511                  * with 16k/4 levels, so we can simply reuse the pud level
 512                  * entry instead.
 513                  */
 514                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 515                 set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
 516                         __pud(__pa(bm_pmd) | PUD_TYPE_TABLE));
 517                 pud_clear_fixmap();
 518         } else {
 519                 BUG();
 520         }
 521
 522         kasan_copy_shadow(pgd);
 523 }
 524
 525 /*
 526  * paging_init() sets up the page tables, initialises the zone memory
 527  * maps and sets up the zero page.
 528  */
 529 void __init paging_init(void)
 530 {
 531         phys_addr_t pgd_phys = early_pgtable_alloc();
 532         pgd_t *pgd = pgd_set_fixmap(pgd_phys);
 533
 534         map_kernel(pgd);
 535         map_mem(pgd);
 536
 537         /*
 538          * We want to reuse the original swapper_pg_dir so we don't have to
 539          * communicate the new address to non-coherent secondaries in
 540          * secondary_entry, and so cpu_switch_mm can generate the address with
 541          * adrp+add rather than a load from some global variable.
 542          *
 543          * To do this we need to go via a temporary pgd.
 544          */
 545         cpu_replace_ttbr1(__va(pgd_phys));
 546         memcpy(swapper_pg_dir, pgd, PAGE_SIZE);
 547         cpu_replace_ttbr1(swapper_pg_dir);
 548
 549         pgd_clear_fixmap();
 550         memblock_free(pgd_phys, PAGE_SIZE);
 551
 552         /*
 553          * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
 554          * allocated with it.
 555          */
 556         memblock_free(__pa(swapper_pg_dir) + PAGE_SIZE,
 557                       SWAPPER_DIR_SIZE - PAGE_SIZE);
 558
 559         bootmem_init();
 560 }
 561
 562 /*
 563  * Check whether a kernel address is valid (derived from arch/x86/).
 564  */
 565 int kern_addr_valid(unsigned long addr)
 566 {
 567         pgd_t *pgd;
 568         pud_t *pud;
 569         pmd_t *pmd;
 570         pte_t *pte;
 571
 572         if ((((long)addr) >> VA_BITS) != -1UL)
 573                 return 0;
 574
 575         pgd = pgd_offset_k(addr);
 576         if (pgd_none(*pgd))
 577                 return 0;
 578
 579         pud = pud_offset(pgd, addr);
 580         if (pud_none(*pud))
 581                 return 0;
 582
 583         if (pud_sect(*pud))
 584                 return pfn_valid(pud_pfn(*pud));
 585
 586         pmd = pmd_offset(pud, addr);
 587         if (pmd_none(*pmd))
 588                 return 0;
 589
 590         if (pmd_sect(*pmd))
 591                 return pfn_valid(pmd_pfn(*pmd));
 592
 593         pte = pte_offset_kernel(pmd, addr);
 594         if (pte_none(*pte))
 595                 return 0;
 596
 597         return pfn_valid(pte_pfn(*pte));
 598 }
 599 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 600 #if !ARM64_SWAPPER_USES_SECTION_MAPS
 601 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 602 {
 603         return vmemmap_populate_basepages(start, end, node);
 604 }
 605 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
 606 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 607 {
 608         unsigned long addr = start;
 609         unsigned long next;
 610         pgd_t *pgd;
 611         pud_t *pud;
 612         pmd_t *pmd;
 613
 614         do {
 615                 next = pmd_addr_end(addr, end);
 616
 617                 pgd = vmemmap_pgd_populate(addr, node);
 618                 if (!pgd)
 619                         return -ENOMEM;
 620
 621                 pud = vmemmap_pud_populate(pgd, addr, node);
 622                 if (!pud)
 623                         return -ENOMEM;
 624
 625                 pmd = pmd_offset(pud, addr);
 626                 if (pmd_none(*pmd)) {
 627                         void *p = NULL;
 628
 629                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
 630                         if (!p)
 631                                 return -ENOMEM;
 632
 633                         set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
 634                 } else
 635                         vmemmap_verify((pte_t *)pmd, node, addr, next);
 636         } while (addr = next, addr != end);
 637
 638         return 0;
 639 }
 640 #endif  /* CONFIG_ARM64_64K_PAGES */
 641 void vmemmap_free(unsigned long start, unsigned long end)
 642 {
 643 }
 644 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
 645
 646 static inline pud_t * fixmap_pud(unsigned long addr)
 647 {
 648         pgd_t *pgd = pgd_offset_k(addr);
 649
 650         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 651
 652         return pud_offset_kimg(pgd, addr);
 653 }
 654
 655 static inline pmd_t * fixmap_pmd(unsigned long addr)
 656 {
 657         pud_t *pud = fixmap_pud(addr);
 658
 659         BUG_ON(pud_none(*pud) || pud_bad(*pud));
 660
 661         return pmd_offset_kimg(pud, addr);
 662 }
 663
 664 static inline pte_t * fixmap_pte(unsigned long addr)
 665 {
 666         return &bm_pte[pte_index(addr)];
 667 }
 668
 669 void __init early_fixmap_init(void)
 670 {
 671         pgd_t *pgd;
 672         pud_t *pud;
 673         pmd_t *pmd;
 674         unsigned long addr = FIXADDR_START;
 675
 676         pgd = pgd_offset_k(addr);
 677         if (CONFIG_PGTABLE_LEVELS > 3 &&
 678             !(pgd_none(*pgd) || pgd_page_paddr(*pgd) == __pa(bm_pud))) {
 679                 /*
 680                  * We only end up here if the kernel mapping and the fixmap
 681                  * share the top level pgd entry, which should only happen on
 682                  * 16k/4 levels configurations.
 683                  */
 684                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 685                 pud = pud_offset_kimg(pgd, addr);
 686         } else {
 687                 pgd_populate(&init_mm, pgd, bm_pud);
 688                 pud = fixmap_pud(addr);
 689         }
 690         pud_populate(&init_mm, pud, bm_pmd);
 691         pmd = fixmap_pmd(addr);
 692         pmd_populate_kernel(&init_mm, pmd, bm_pte);
 693
 694         /*
 695          * The boot-ioremap range spans multiple pmds, for which
 696          * we are not prepared:
 697          */
 698         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 699                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 700
 701         if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
 702              || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 703                 WARN_ON(1);
 704                 pr_warn("pmd %p != %p, %p\n",
 705                         pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
 706                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
 707                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 708                         fix_to_virt(FIX_BTMAP_BEGIN));
 709                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 710                         fix_to_virt(FIX_BTMAP_END));
 711
 712                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 713                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
 714         }
 715 }
 716
 717 void __set_fixmap(enum fixed_addresses idx,
 718                                phys_addr_t phys, pgprot_t flags)
 719 {
 720         unsigned long addr = __fix_to_virt(idx);
 721         pte_t *pte;
 722
 723         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 724
 725         pte = fixmap_pte(addr);
 726
 727         if (pgprot_val(flags)) {
 728                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 729         } else {
 730                 pte_clear(&init_mm, addr, pte);
 731                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 732         }
 733 }
 734
 735 void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 736 {
 737         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
 738         int offset;
 739         void *dt_virt;
 740
 741         /*
 742          * Check whether the physical FDT address is set and meets the minimum
 743          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
 744          * at least 8 bytes so that we can always access the size field of the
 745          * FDT header after mapping the first chunk, double check here if that
 746          * is indeed the case.
 747          */
 748         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 749         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
 750                 return NULL;
 751
 752         /*
 753          * Make sure that the FDT region can be mapped without the need to
 754          * allocate additional translation table pages, so that it is safe
 755          * to call create_mapping_noalloc() this early.
 756          *
 757          * On 64k pages, the FDT will be mapped using PTEs, so we need to
 758          * be in the same PMD as the rest of the fixmap.
 759          * On 4k pages, we'll use section mappings for the FDT so we only
 760          * have to be in the same PUD.
 761          */
 762         BUILD_BUG_ON(dt_virt_base % SZ_2M);
 763
 764         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
 765                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
 766
 767         offset = dt_phys % SWAPPER_BLOCK_SIZE;
 768         dt_virt = (void *)dt_virt_base + offset;
 769
 770         /* map the first chunk so we can read the size from the header */
 771         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
 772                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 773
 774         if (fdt_check_header(dt_virt) != 0)
 775                 return NULL;
 776
 777         *size = fdt_totalsize(dt_virt);
 778         if (*size > MAX_FDT_SIZE)
 779                 return NULL;
 780
 781         if (offset + *size > SWAPPER_BLOCK_SIZE)
 782                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 783                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
 784
 785         return dt_virt;
 786 }
 787
 788 void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 789 {
 790         void *dt_virt;
 791         int size;
 792
 793         dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
 794         if (!dt_virt)
 795                 return NULL;
 796
 797         memblock_reserve(dt_phys, size);
 798         return dt_virt;
 799 }
 800
 801 int __init arch_ioremap_pud_supported(void)
 802 {
 803         /* only 4k granule supports level 1 block mappings */
 804         return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
 805 }
 806
 807 int __init arch_ioremap_pmd_supported(void)
 808 {
 809         return 1;
 810 }
 811
 812 int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
 813 {
 814         BUG_ON(phys & ~PUD_MASK);
 815         set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 816         return 1;
 817 }
 818
 819 int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
 820 {
 821         BUG_ON(phys & ~PMD_MASK);
 822         set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 823         return 1;
 824 }
 825
 826 int pud_clear_huge(pud_t *pud)
 827 {
 828         if (!pud_sect(*pud))
 829                 return 0;
 830         pud_clear(pud);
 831         return 1;
 832 }
 833
 834 int pmd_clear_huge(pmd_t *pmd)
 835 {
 836         if (!pmd_sect(*pmd))
 837                 return 0;
 838         pmd_clear(pmd);
 839         return 1;
 840 }