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