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 #include <linux/mm.h>
  33
  34 #include <asm/barrier.h>
  35 #include <asm/cputype.h>
  36 #include <asm/fixmap.h>
  37 #include <asm/kasan.h>
  38 #include <asm/kernel-pgtable.h>
  39 #include <asm/sections.h>
  40 #include <asm/setup.h>
  41 #include <asm/sizes.h>
  42 #include <asm/tlb.h>
  43 #include <asm/memblock.h>
  44 #include <asm/mmu_context.h>
  45
  46 #include "mm.h"
  47
  48 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
  49
  50 u64 kimage_voffset __read_mostly;
  51 EXPORT_SYMBOL(kimage_voffset);
  52
  53 /*
  54  * Empty_zero_page is a special page that is used for zero-initialized data
  55  * and COW.
  56  */
  57 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
  58 EXPORT_SYMBOL(empty_zero_page);
  59
  60 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
  61 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
  62 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
  63
  64 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
  65                               unsigned long size, pgprot_t vma_prot)
  66 {
  67         if (!pfn_valid(pfn))
  68                 return pgprot_noncached(vma_prot);
  69         else if (file->f_flags & O_SYNC)
  70                 return pgprot_writecombine(vma_prot);
  71         return vma_prot;
  72 }
  73 EXPORT_SYMBOL(phys_mem_access_prot);
  74
  75 static phys_addr_t __init early_pgtable_alloc(void)
  76 {
  77         phys_addr_t phys;
  78         void *ptr;
  79
  80         phys = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
  81         BUG_ON(!phys);
  82
  83         /*
  84          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
  85          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
  86          * any level of table.
  87          */
  88         ptr = pte_set_fixmap(phys);
  89
  90         memset(ptr, 0, PAGE_SIZE);
  91
  92         /*
  93          * Implicit barriers also ensure the zeroed page is visible to the page
  94          * table walker
  95          */
  96         pte_clear_fixmap();
  97
  98         return phys;
  99 }
 100
 101 /*
 102  * remap a PMD into pages
 103  */
 104 static void split_pmd(pmd_t *pmd, pte_t *pte)
 105 {
 106         unsigned long pfn = pmd_pfn(*pmd);
 107         int i = 0;
 108
 109         do {
 110                 /*
 111                  * Need to have the least restrictive permissions available
 112                  * permissions will be fixed up later
 113                  */
 114                 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 115                 pfn++;
 116         } while (pte++, i++, i < PTRS_PER_PTE);
 117 }
 118
 119 static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 120                                   unsigned long end, unsigned long pfn,
 121                                   pgprot_t prot,
 122                                   phys_addr_t (*pgtable_alloc)(void))
 123 {
 124         pte_t *pte;
 125
 126         if (pmd_none(*pmd) || pmd_sect(*pmd)) {
 127                 phys_addr_t pte_phys;
 128                 BUG_ON(!pgtable_alloc);
 129                 pte_phys = pgtable_alloc();
 130                 pte = pte_set_fixmap(pte_phys);
 131                 if (pmd_sect(*pmd))
 132                         split_pmd(pmd, pte);
 133                 __pmd_populate(pmd, pte_phys, PMD_TYPE_TABLE);
 134                 flush_tlb_all();
 135                 pte_clear_fixmap();
 136         }
 137         BUG_ON(pmd_bad(*pmd));
 138
 139         pte = pte_set_fixmap_offset(pmd, addr);
 140         do {
 141                 set_pte(pte, pfn_pte(pfn, prot));
 142                 pfn++;
 143         } while (pte++, addr += PAGE_SIZE, addr != end);
 144
 145         pte_clear_fixmap();
 146 }
 147
 148 static void split_pud(pud_t *old_pud, pmd_t *pmd)
 149 {
 150         unsigned long addr = pud_pfn(*old_pud) << PAGE_SHIFT;
 151         pgprot_t prot = __pgprot(pud_val(*old_pud) ^ addr);
 152         int i = 0;
 153
 154         do {
 155                 set_pmd(pmd, __pmd(addr | pgprot_val(prot)));
 156                 addr += PMD_SIZE;
 157         } while (pmd++, i++, i < PTRS_PER_PMD);
 158 }
 159
 160 #ifdef CONFIG_DEBUG_PAGEALLOC
 161 static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
 162 {
 163
 164         /*
 165          * If debug_page_alloc is enabled we must map the linear map
 166          * using pages. However, other mappings created by
 167          * create_mapping_noalloc must use sections in some cases. Allow
 168          * sections to be used in those cases, where no pgtable_alloc
 169          * function is provided.
 170          */
 171         return !pgtable_alloc || !debug_pagealloc_enabled();
 172 }
 173 #else
 174 static bool block_mappings_allowed(phys_addr_t (*pgtable_alloc)(void))
 175 {
 176         return true;
 177 }
 178 #endif
 179
 180 static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 181                                   phys_addr_t phys, pgprot_t prot,
 182                                   phys_addr_t (*pgtable_alloc)(void))
 183 {
 184         pmd_t *pmd;
 185         unsigned long next;
 186
 187         /*
 188          * Check for initial section mappings in the pgd/pud and remove them.
 189          */
 190         if (pud_none(*pud) || pud_sect(*pud)) {
 191                 phys_addr_t pmd_phys;
 192                 BUG_ON(!pgtable_alloc);
 193                 pmd_phys = pgtable_alloc();
 194                 pmd = pmd_set_fixmap(pmd_phys);
 195                 if (pud_sect(*pud)) {
 196                         /*
 197                          * need to have the 1G of mappings continue to be
 198                          * present
 199                          */
 200                         split_pud(pud, pmd);
 201                 }
 202                 __pud_populate(pud, pmd_phys, PUD_TYPE_TABLE);
 203                 flush_tlb_all();
 204                 pmd_clear_fixmap();
 205         }
 206         BUG_ON(pud_bad(*pud));
 207
 208         pmd = pmd_set_fixmap_offset(pud, addr);
 209         do {
 210                 next = pmd_addr_end(addr, end);
 211                 /* try section mapping first */
 212                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
 213                       block_mappings_allowed(pgtable_alloc)) {
 214                         pmd_t old_pmd =*pmd;
 215                         pmd_set_huge(pmd, phys, 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                         pud_set_huge(pud, phys, prot);
 276
 277                         /*
 278                          * If we have an old value for a pud, it will
 279                          * be pointing to a pmd table that we no longer
 280                          * need (from swapper_pg_dir).
 281                          *
 282                          * Look up the old pmd table and free it.
 283                          */
 284                         if (!pud_none(old_pud)) {
 285                                 flush_tlb_all();
 286                                 if (pud_table(old_pud)) {
 287                                         phys_addr_t table = pud_page_paddr(old_pud);
 288                                         if (!WARN_ON_ONCE(slab_is_available()))
 289                                                 memblock_free(table, PAGE_SIZE);
 290                                 }
 291                         }
 292                 } else {
 293                         alloc_init_pmd(pud, addr, next, phys, prot,
 294                                        pgtable_alloc);
 295                 }
 296                 phys += next - addr;
 297         } while (pud++, addr = next, addr != end);
 298
 299         pud_clear_fixmap();
 300 }
 301
 302 /*
 303  * Create the page directory entries and any necessary page tables for the
 304  * mapping specified by 'md'.
 305  */
 306 static void init_pgd(pgd_t *pgd, phys_addr_t phys, unsigned long virt,
 307                                     phys_addr_t size, pgprot_t prot,
 308                                     phys_addr_t (*pgtable_alloc)(void))
 309 {
 310         unsigned long addr, length, end, next;
 311
 312         /*
 313          * If the virtual and physical address don't have the same offset
 314          * within a page, we cannot map the region as the caller expects.
 315          */
 316         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
 317                 return;
 318
 319         phys &= PAGE_MASK;
 320         addr = virt & PAGE_MASK;
 321         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
 322
 323         end = addr + length;
 324         do {
 325                 next = pgd_addr_end(addr, end);
 326                 alloc_init_pud(pgd, addr, next, phys, prot, pgtable_alloc);
 327                 phys += next - addr;
 328         } while (pgd++, addr = next, addr != end);
 329 }
 330
 331 static phys_addr_t late_pgtable_alloc(void)
 332 {
 333         void *ptr = (void *)__get_free_page(PGALLOC_GFP);
 334         BUG_ON(!ptr);
 335
 336         /* Ensure the zeroed page is visible to the page table walker */
 337         dsb(ishst);
 338         return __pa(ptr);
 339 }
 340
 341 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 342                                  unsigned long virt, phys_addr_t size,
 343                                  pgprot_t prot,
 344                                  phys_addr_t (*alloc)(void))
 345 {
 346         init_pgd(pgd_offset_raw(pgdir, virt), phys, virt, size, prot, alloc);
 347 }
 348
 349 /*
 350  * This function can only be used to modify existing table entries,
 351  * without allocating new levels of table. Note that this permits the
 352  * creation of new section or page entries.
 353  */
 354 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 355                                   phys_addr_t size, pgprot_t prot)
 356 {
 357         if (virt < VMALLOC_START) {
 358                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 359                         &phys, virt);
 360                 return;
 361         }
 362         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 363                              NULL);
 364 }
 365
 366 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 367                                unsigned long virt, phys_addr_t size,
 368                                pgprot_t prot)
 369 {
 370         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
 371                              late_pgtable_alloc);
 372 }
 373
 374 static void create_mapping_late(phys_addr_t phys, unsigned long virt,
 375                                   phys_addr_t size, pgprot_t prot)
 376 {
 377         if (virt < VMALLOC_START) {
 378                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 379                         &phys, virt);
 380                 return;
 381         }
 382
 383         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
 384                              late_pgtable_alloc);
 385 }
 386
 387 static void __init __map_memblock(pgd_t *pgd, phys_addr_t start, phys_addr_t end)
 388 {
 389         unsigned long kernel_start = __pa_symbol(_stext);
 390         unsigned long kernel_end = __pa_symbol(__init_begin);
 391
 392         /*
 393          * Take care not to create a writable alias for the
 394          * read-only text and rodata sections of the kernel image.
 395          */
 396
 397         /* No overlap with the kernel text/rodata */
 398         if (end < kernel_start || start >= kernel_end) {
 399                 __create_pgd_mapping(pgd, start, __phys_to_virt(start),
 400                                      end - start, PAGE_KERNEL,
 401                                      early_pgtable_alloc);
 402                 return;
 403         }
 404
 405         /*
 406          * This block overlaps the kernel text/rodata mapping.
 407          * Map the portion(s) which don't overlap.
 408          */
 409         if (start < kernel_start)
 410                 __create_pgd_mapping(pgd, start,
 411                                      __phys_to_virt(start),
 412                                      kernel_start - start, PAGE_KERNEL,
 413                                      early_pgtable_alloc);
 414         if (kernel_end < end)
 415                 __create_pgd_mapping(pgd, kernel_end,
 416                                      __phys_to_virt(kernel_end),
 417                                      end - kernel_end, PAGE_KERNEL,
 418                                      early_pgtable_alloc);
 419
 420         /*
 421          * Map the linear alias of the [_stext, __init_begin) interval as
 422          * read-only/non-executable. This makes the contents of the
 423          * region accessible to subsystems such as hibernate, but
 424          * protects it from inadvertent modification or execution.
 425          */
 426         __create_pgd_mapping(pgd, kernel_start, __phys_to_virt(kernel_start),
 427                              kernel_end - kernel_start, PAGE_KERNEL_RO,
 428                              early_pgtable_alloc);
 429 }
 430
 431 static void __init map_mem(pgd_t *pgd)
 432 {
 433         struct memblock_region *reg;
 434
 435         /* map all the memory banks */
 436         for_each_memblock(memory, reg) {
 437                 phys_addr_t start = reg->base;
 438                 phys_addr_t end = start + reg->size;
 439
 440                 if (start >= end)
 441                         break;
 442                 if (memblock_is_nomap(reg))
 443                         continue;
 444
 445                 __map_memblock(pgd, start, end);
 446         }
 447 }
 448
 449 void mark_rodata_ro(void)
 450 {
 451         unsigned long section_size;
 452
 453         section_size = (unsigned long)_etext - (unsigned long)_stext;
 454         create_mapping_late(__pa_symbol(_stext), (unsigned long)_stext,
 455                             section_size, PAGE_KERNEL_ROX);
 456         /*
 457          * mark .rodata as read only. Use __init_begin rather than __end_rodata
 458          * to cover NOTES and EXCEPTION_TABLE.
 459          */
 460         section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
 461         create_mapping_late(__pa_symbol(__start_rodata),
 462                             (unsigned long)__start_rodata,
 463                             section_size, PAGE_KERNEL_RO);
 464 }
 465
 466 void fixup_init(void)
 467 {
 468         /*
 469          * Unmap the __init region but leave the VM area in place. This
 470          * prevents the region from being reused for kernel modules, which
 471          * is not supported by kallsyms.
 472          */
 473         unmap_kernel_range((u64)__init_begin, (u64)(__init_end - __init_begin));
 474 }
 475
 476 static void __init map_kernel_chunk(pgd_t *pgd, void *va_start, void *va_end,
 477                                     pgprot_t prot, struct vm_struct *vma)
 478 {
 479         phys_addr_t pa_start = __pa_symbol(va_start);
 480         unsigned long size = va_end - va_start;
 481
 482         BUG_ON(!PAGE_ALIGNED(pa_start));
 483         BUG_ON(!PAGE_ALIGNED(size));
 484
 485         __create_pgd_mapping(pgd, pa_start, (unsigned long)va_start, size, prot,
 486                              early_pgtable_alloc);
 487
 488         vma->addr       = va_start;
 489         vma->phys_addr  = pa_start;
 490         vma->size       = size;
 491         vma->flags      = VM_MAP;
 492         vma->caller     = __builtin_return_address(0);
 493
 494         vm_area_add_early(vma);
 495 }
 496
 497 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 498 static int __init map_entry_trampoline(void)
 499 {
 500         extern char __entry_tramp_text_start[];
 501
 502         pgprot_t prot = PAGE_KERNEL_ROX;
 503         phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
 504
 505         /* The trampoline is always mapped and can therefore be global */
 506         pgprot_val(prot) &= ~PTE_NG;
 507
 508         /* Map only the text into the trampoline page table */
 509         memset(tramp_pg_dir, 0, PGD_SIZE);
 510         __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
 511                              prot, late_pgtable_alloc);
 512
 513         /* Map both the text and data into the kernel page table */
 514         __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
 515         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 516                 extern char __entry_tramp_data_start[];
 517
 518                 __set_fixmap(FIX_ENTRY_TRAMP_DATA,
 519                              __pa_symbol(__entry_tramp_data_start),
 520                              PAGE_KERNEL_RO);
 521         }
 522
 523         return 0;
 524 }
 525 core_initcall(map_entry_trampoline);
 526 #endif
 527
 528 /*
 529  * Create fine-grained mappings for the kernel.
 530  */
 531 static void __init map_kernel(pgd_t *pgd)
 532 {
 533         static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_init, vmlinux_data;
 534
 535         map_kernel_chunk(pgd, _stext, _etext, PAGE_KERNEL_EXEC, &vmlinux_text);
 536         map_kernel_chunk(pgd, __start_rodata, __init_begin, PAGE_KERNEL, &vmlinux_rodata);
 537         map_kernel_chunk(pgd, __init_begin, __init_end, PAGE_KERNEL_EXEC,
 538                          &vmlinux_init);
 539         map_kernel_chunk(pgd, _data, _end, PAGE_KERNEL, &vmlinux_data);
 540
 541         if (!pgd_val(*pgd_offset_raw(pgd, FIXADDR_START))) {
 542                 /*
 543                  * The fixmap falls in a separate pgd to the kernel, and doesn't
 544                  * live in the carveout for the swapper_pg_dir. We can simply
 545                  * re-use the existing dir for the fixmap.
 546                  */
 547                 set_pgd(pgd_offset_raw(pgd, FIXADDR_START),
 548                         *pgd_offset_k(FIXADDR_START));
 549         } else if (CONFIG_PGTABLE_LEVELS > 3) {
 550                 /*
 551                  * The fixmap shares its top level pgd entry with the kernel
 552                  * mapping. This can really only occur when we are running
 553                  * with 16k/4 levels, so we can simply reuse the pud level
 554                  * entry instead.
 555                  */
 556                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 557                 set_pud(pud_set_fixmap_offset(pgd, FIXADDR_START),
 558                         __pud(__pa_symbol(bm_pmd) | PUD_TYPE_TABLE));
 559                 pud_clear_fixmap();
 560         } else {
 561                 BUG();
 562         }
 563
 564         kasan_copy_shadow(pgd);
 565 }
 566
 567 /*
 568  * paging_init() sets up the page tables, initialises the zone memory
 569  * maps and sets up the zero page.
 570  */
 571 void __init paging_init(void)
 572 {
 573         phys_addr_t pgd_phys = early_pgtable_alloc();
 574         pgd_t *pgd = pgd_set_fixmap(pgd_phys);
 575
 576         map_kernel(pgd);
 577         map_mem(pgd);
 578
 579         /*
 580          * We want to reuse the original swapper_pg_dir so we don't have to
 581          * communicate the new address to non-coherent secondaries in
 582          * secondary_entry, and so cpu_switch_mm can generate the address with
 583          * adrp+add rather than a load from some global variable.
 584          *
 585          * To do this we need to go via a temporary pgd.
 586          */
 587         cpu_replace_ttbr1(__va(pgd_phys));
 588         memcpy(swapper_pg_dir, pgd, PAGE_SIZE);
 589         cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 590
 591         pgd_clear_fixmap();
 592         memblock_free(pgd_phys, PAGE_SIZE);
 593
 594         /* Ensure the zero page is visible to the page table walker */
 595         dsb(ishst);
 596
 597         /*
 598          * We only reuse the PGD from the swapper_pg_dir, not the pud + pmd
 599          * allocated with it.
 600          */
 601         memblock_free(__pa_symbol(swapper_pg_dir) + PAGE_SIZE,
 602                       SWAPPER_DIR_SIZE - PAGE_SIZE);
 603
 604         bootmem_init();
 605 }
 606
 607 /*
 608  * Check whether a kernel address is valid (derived from arch/x86/).
 609  */
 610 int kern_addr_valid(unsigned long addr)
 611 {
 612         pgd_t *pgd;
 613         pud_t *pud;
 614         pmd_t *pmd;
 615         pte_t *pte;
 616
 617         if ((((long)addr) >> VA_BITS) != -1UL)
 618                 return 0;
 619
 620         pgd = pgd_offset_k(addr);
 621         if (pgd_none(*pgd))
 622                 return 0;
 623
 624         pud = pud_offset(pgd, addr);
 625         if (pud_none(*pud))
 626                 return 0;
 627
 628         if (pud_sect(*pud))
 629                 return pfn_valid(pud_pfn(*pud));
 630
 631         pmd = pmd_offset(pud, addr);
 632         if (pmd_none(*pmd))
 633                 return 0;
 634
 635         if (pmd_sect(*pmd))
 636                 return pfn_valid(pmd_pfn(*pmd));
 637
 638         pte = pte_offset_kernel(pmd, addr);
 639         if (pte_none(*pte))
 640                 return 0;
 641
 642         return pfn_valid(pte_pfn(*pte));
 643 }
 644 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 645 #if !ARM64_SWAPPER_USES_SECTION_MAPS
 646 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 647 {
 648         return vmemmap_populate_basepages(start, end, node);
 649 }
 650 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
 651 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
 652 {
 653         unsigned long addr = start;
 654         unsigned long next;
 655         pgd_t *pgd;
 656         pud_t *pud;
 657         pmd_t *pmd;
 658
 659         do {
 660                 next = pmd_addr_end(addr, end);
 661
 662                 pgd = vmemmap_pgd_populate(addr, node);
 663                 if (!pgd)
 664                         return -ENOMEM;
 665
 666                 pud = vmemmap_pud_populate(pgd, addr, node);
 667                 if (!pud)
 668                         return -ENOMEM;
 669
 670                 pmd = pmd_offset(pud, addr);
 671                 if (pmd_none(*pmd)) {
 672                         void *p = NULL;
 673
 674                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
 675                         if (!p)
 676                                 return -ENOMEM;
 677
 678                         set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
 679                 } else
 680                         vmemmap_verify((pte_t *)pmd, node, addr, next);
 681         } while (addr = next, addr != end);
 682
 683         return 0;
 684 }
 685 #endif  /* CONFIG_ARM64_64K_PAGES */
 686 void vmemmap_free(unsigned long start, unsigned long end)
 687 {
 688 }
 689 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
 690
 691 static inline pud_t * fixmap_pud(unsigned long addr)
 692 {
 693         pgd_t *pgd = pgd_offset_k(addr);
 694
 695         BUG_ON(pgd_none(*pgd) || pgd_bad(*pgd));
 696
 697         return pud_offset_kimg(pgd, addr);
 698 }
 699
 700 static inline pmd_t * fixmap_pmd(unsigned long addr)
 701 {
 702         pud_t *pud = fixmap_pud(addr);
 703
 704         BUG_ON(pud_none(*pud) || pud_bad(*pud));
 705
 706         return pmd_offset_kimg(pud, addr);
 707 }
 708
 709 static inline pte_t * fixmap_pte(unsigned long addr)
 710 {
 711         return &bm_pte[pte_index(addr)];
 712 }
 713
 714 /*
 715  * The p*d_populate functions call virt_to_phys implicitly so they can't be used
 716  * directly on kernel symbols (bm_p*d). This function is called too early to use
 717  * lm_alias so __p*d_populate functions must be used to populate with the
 718  * physical address from __pa_symbol.
 719  */
 720 void __init early_fixmap_init(void)
 721 {
 722         pgd_t *pgd;
 723         pud_t *pud;
 724         pmd_t *pmd;
 725         unsigned long addr = FIXADDR_START;
 726
 727         pgd = pgd_offset_k(addr);
 728         if (CONFIG_PGTABLE_LEVELS > 3 &&
 729             !(pgd_none(*pgd) || pgd_page_paddr(*pgd) == __pa_symbol(bm_pud))) {
 730                 /*
 731                  * We only end up here if the kernel mapping and the fixmap
 732                  * share the top level pgd entry, which should only happen on
 733                  * 16k/4 levels configurations.
 734                  */
 735                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 736                 pud = pud_offset_kimg(pgd, addr);
 737         } else {
 738                 if (pgd_none(*pgd))
 739                         __pgd_populate(pgd, __pa_symbol(bm_pud),
 740                                        PUD_TYPE_TABLE);
 741                 pud = fixmap_pud(addr);
 742         }
 743         if (pud_none(*pud))
 744                 __pud_populate(pud, __pa_symbol(bm_pmd), PMD_TYPE_TABLE);
 745         pmd = fixmap_pmd(addr);
 746         __pmd_populate(pmd, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
 747
 748         /*
 749          * The boot-ioremap range spans multiple pmds, for which
 750          * we are not prepared:
 751          */
 752         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 753                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 754
 755         if ((pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
 756              || pmd != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 757                 WARN_ON(1);
 758                 pr_warn("pmd %p != %p, %p\n",
 759                         pmd, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
 760                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
 761                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 762                         fix_to_virt(FIX_BTMAP_BEGIN));
 763                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 764                         fix_to_virt(FIX_BTMAP_END));
 765
 766                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 767                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
 768         }
 769 }
 770
 771 void __set_fixmap(enum fixed_addresses idx,
 772                                phys_addr_t phys, pgprot_t flags)
 773 {
 774         unsigned long addr = __fix_to_virt(idx);
 775         pte_t *pte;
 776
 777         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 778
 779         pte = fixmap_pte(addr);
 780
 781         if (pgprot_val(flags)) {
 782                 set_pte(pte, pfn_pte(phys >> PAGE_SHIFT, flags));
 783         } else {
 784                 pte_clear(&init_mm, addr, pte);
 785                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 786         }
 787 }
 788
 789 void *__init __fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 790 {
 791         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
 792         int offset;
 793         void *dt_virt;
 794
 795         /*
 796          * Check whether the physical FDT address is set and meets the minimum
 797          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
 798          * at least 8 bytes so that we can always access the magic and size
 799          * fields of the FDT header after mapping the first chunk, double check
 800          * here if that is indeed the case.
 801          */
 802         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 803         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
 804                 return NULL;
 805
 806         /*
 807          * Make sure that the FDT region can be mapped without the need to
 808          * allocate additional translation table pages, so that it is safe
 809          * to call create_mapping_noalloc() this early.
 810          *
 811          * On 64k pages, the FDT will be mapped using PTEs, so we need to
 812          * be in the same PMD as the rest of the fixmap.
 813          * On 4k pages, we'll use section mappings for the FDT so we only
 814          * have to be in the same PUD.
 815          */
 816         BUILD_BUG_ON(dt_virt_base % SZ_2M);
 817
 818         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
 819                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
 820
 821         offset = dt_phys % SWAPPER_BLOCK_SIZE;
 822         dt_virt = (void *)dt_virt_base + offset;
 823
 824         /* map the first chunk so we can read the size from the header */
 825         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
 826                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 827
 828         if (fdt_magic(dt_virt) != FDT_MAGIC)
 829                 return NULL;
 830
 831         *size = fdt_totalsize(dt_virt);
 832         if (*size > MAX_FDT_SIZE)
 833                 return NULL;
 834
 835         if (offset + *size > SWAPPER_BLOCK_SIZE)
 836                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 837                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
 838
 839         return dt_virt;
 840 }
 841
 842 void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
 843 {
 844         void *dt_virt;
 845         int size;
 846
 847         dt_virt = __fixmap_remap_fdt(dt_phys, &size, PAGE_KERNEL_RO);
 848         if (!dt_virt)
 849                 return NULL;
 850
 851         memblock_reserve(dt_phys, size);
 852         return dt_virt;
 853 }
 854
 855 int __init arch_ioremap_pud_supported(void)
 856 {
 857         /* only 4k granule supports level 1 block mappings */
 858         return IS_ENABLED(CONFIG_ARM64_4K_PAGES);
 859 }
 860
 861 int __init arch_ioremap_pmd_supported(void)
 862 {
 863         return 1;
 864 }
 865
 866 int pud_set_huge(pud_t *pud, phys_addr_t phys, pgprot_t prot)
 867 {
 868         BUG_ON(phys & ~PUD_MASK);
 869         set_pud(pud, __pud(phys | PUD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 870         return 1;
 871 }
 872
 873 int pmd_set_huge(pmd_t *pmd, phys_addr_t phys, pgprot_t prot)
 874 {
 875         BUG_ON(phys & ~PMD_MASK);
 876         set_pmd(pmd, __pmd(phys | PMD_TYPE_SECT | pgprot_val(mk_sect_prot(prot))));
 877         return 1;
 878 }
 879
 880 int pud_clear_huge(pud_t *pud)
 881 {
 882         if (!pud_sect(*pud))
 883                 return 0;
 884         pud_clear(pud);
 885         return 1;
 886 }
 887
 888 int pmd_clear_huge(pmd_t *pmd)
 889 {
 890         if (!pmd_sect(*pmd))
 891                 return 0;
 892         pmd_clear(pmd);
 893         return 1;
 894 }
 895
 896 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 897 int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 898 {
 899         return pud_none(*pud);
 900 }
 901
 902 int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 903 {
 904         return pmd_none(*pmd);
 905 }
 906 #endif