arch/arm64/mm/mmu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Based on arch/arm/mm/mmu.c
   4  *
   5  * Copyright (C) 1995-2005 Russell King
   6  * Copyright (C) 2012 ARM Ltd.
   7  */
   8
   9 #include <linux/cache.h>
  10 #include <linux/export.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/init.h>
  14 #include <linux/ioport.h>
  15 #include <linux/kexec.h>
  16 #include <linux/libfdt.h>
  17 #include <linux/mman.h>
  18 #include <linux/nodemask.h>
  19 #include <linux/memblock.h>
  20 #include <linux/memory.h>
  21 #include <linux/fs.h>
  22 #include <linux/io.h>
  23 #include <linux/mm.h>
  24 #include <linux/vmalloc.h>
  25
  26 #include <asm/barrier.h>
  27 #include <asm/cputype.h>
  28 #include <asm/fixmap.h>
  29 #include <asm/kasan.h>
  30 #include <asm/kernel-pgtable.h>
  31 #include <asm/sections.h>
  32 #include <asm/setup.h>
  33 #include <linux/sizes.h>
  34 #include <asm/tlb.h>
  35 #include <asm/mmu_context.h>
  36 #include <asm/ptdump.h>
  37 #include <asm/tlbflush.h>
  38
  39 #define NO_BLOCK_MAPPINGS       BIT(0)
  40 #define NO_CONT_MAPPINGS        BIT(1)
  41
  42 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
  43 u64 idmap_ptrs_per_pgd = PTRS_PER_PGD;
  44
  45 u64 __section(".mmuoff.data.write") vabits_actual;
  46 EXPORT_SYMBOL(vabits_actual);
  47
  48 u64 kimage_voffset __ro_after_init;
  49 EXPORT_SYMBOL(kimage_voffset);
  50
  51 /*
  52  * Empty_zero_page is a special page that is used for zero-initialized data
  53  * and COW.
  54  */
  55 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
  56 EXPORT_SYMBOL(empty_zero_page);
  57
  58 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
  59 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
  60 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
  61
  62 static DEFINE_SPINLOCK(swapper_pgdir_lock);
  63
  64 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
  65 {
  66         pgd_t *fixmap_pgdp;
  67
  68         spin_lock(&swapper_pgdir_lock);
  69         fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
  70         WRITE_ONCE(*fixmap_pgdp, pgd);
  71         /*
  72          * We need dsb(ishst) here to ensure the page-table-walker sees
  73          * our new entry before set_p?d() returns. The fixmap's
  74          * flush_tlb_kernel_range() via clear_fixmap() does this for us.
  75          */
  76         pgd_clear_fixmap();
  77         spin_unlock(&swapper_pgdir_lock);
  78 }
  79
  80 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
  81                               unsigned long size, pgprot_t vma_prot)
  82 {
  83         if (!pfn_valid(pfn))
  84                 return pgprot_noncached(vma_prot);
  85         else if (file->f_flags & O_SYNC)
  86                 return pgprot_writecombine(vma_prot);
  87         return vma_prot;
  88 }
  89 EXPORT_SYMBOL(phys_mem_access_prot);
  90
  91 static phys_addr_t __init early_pgtable_alloc(int shift)
  92 {
  93         phys_addr_t phys;
  94         void *ptr;
  95
  96         phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
  97         if (!phys)
  98                 panic("Failed to allocate page table page\n");
  99
 100         /*
 101          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
 102          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
 103          * any level of table.
 104          */
 105         ptr = pte_set_fixmap(phys);
 106
 107         memset(ptr, 0, PAGE_SIZE);
 108
 109         /*
 110          * Implicit barriers also ensure the zeroed page is visible to the page
 111          * table walker
 112          */
 113         pte_clear_fixmap();
 114
 115         return phys;
 116 }
 117
 118 static bool pgattr_change_is_safe(u64 old, u64 new)
 119 {
 120         /*
 121          * The following mapping attributes may be updated in live
 122          * kernel mappings without the need for break-before-make.
 123          */
 124         static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG;
 125
 126         /* creating or taking down mappings is always safe */
 127         if (old == 0 || new == 0)
 128                 return true;
 129
 130         /* live contiguous mappings may not be manipulated at all */
 131         if ((old | new) & PTE_CONT)
 132                 return false;
 133
 134         /* Transitioning from Non-Global to Global is unsafe */
 135         if (old & ~new & PTE_NG)
 136                 return false;
 137
 138         return ((old ^ new) & ~mask) == 0;
 139 }
 140
 141 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
 142                      phys_addr_t phys, pgprot_t prot)
 143 {
 144         pte_t *ptep;
 145
 146         ptep = pte_set_fixmap_offset(pmdp, addr);
 147         do {
 148                 pte_t old_pte = READ_ONCE(*ptep);
 149
 150                 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
 151
 152                 /*
 153                  * After the PTE entry has been populated once, we
 154                  * only allow updates to the permission attributes.
 155                  */
 156                 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
 157                                               READ_ONCE(pte_val(*ptep))));
 158
 159                 phys += PAGE_SIZE;
 160         } while (ptep++, addr += PAGE_SIZE, addr != end);
 161
 162         pte_clear_fixmap();
 163 }
 164
 165 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
 166                                 unsigned long end, phys_addr_t phys,
 167                                 pgprot_t prot,
 168                                 phys_addr_t (*pgtable_alloc)(int),
 169                                 int flags)
 170 {
 171         unsigned long next;
 172         pmd_t pmd = READ_ONCE(*pmdp);
 173
 174         BUG_ON(pmd_sect(pmd));
 175         if (pmd_none(pmd)) {
 176                 phys_addr_t pte_phys;
 177                 BUG_ON(!pgtable_alloc);
 178                 pte_phys = pgtable_alloc(PAGE_SHIFT);
 179                 __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
 180                 pmd = READ_ONCE(*pmdp);
 181         }
 182         BUG_ON(pmd_bad(pmd));
 183
 184         do {
 185                 pgprot_t __prot = prot;
 186
 187                 next = pte_cont_addr_end(addr, end);
 188
 189                 /* use a contiguous mapping if the range is suitably aligned */
 190                 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
 191                     (flags & NO_CONT_MAPPINGS) == 0)
 192                         __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
 193
 194                 init_pte(pmdp, addr, next, phys, __prot);
 195
 196                 phys += next - addr;
 197         } while (addr = next, addr != end);
 198 }
 199
 200 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
 201                      phys_addr_t phys, pgprot_t prot,
 202                      phys_addr_t (*pgtable_alloc)(int), int flags)
 203 {
 204         unsigned long next;
 205         pmd_t *pmdp;
 206
 207         pmdp = pmd_set_fixmap_offset(pudp, addr);
 208         do {
 209                 pmd_t old_pmd = READ_ONCE(*pmdp);
 210
 211                 next = pmd_addr_end(addr, end);
 212
 213                 /* try section mapping first */
 214                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
 215                     (flags & NO_BLOCK_MAPPINGS) == 0) {
 216                         pmd_set_huge(pmdp, phys, prot);
 217
 218                         /*
 219                          * After the PMD entry has been populated once, we
 220                          * only allow updates to the permission attributes.
 221                          */
 222                         BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
 223                                                       READ_ONCE(pmd_val(*pmdp))));
 224                 } else {
 225                         alloc_init_cont_pte(pmdp, addr, next, phys, prot,
 226                                             pgtable_alloc, flags);
 227
 228                         BUG_ON(pmd_val(old_pmd) != 0 &&
 229                                pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
 230                 }
 231                 phys += next - addr;
 232         } while (pmdp++, addr = next, addr != end);
 233
 234         pmd_clear_fixmap();
 235 }
 236
 237 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
 238                                 unsigned long end, phys_addr_t phys,
 239                                 pgprot_t prot,
 240                                 phys_addr_t (*pgtable_alloc)(int), int flags)
 241 {
 242         unsigned long next;
 243         pud_t pud = READ_ONCE(*pudp);
 244
 245         /*
 246          * Check for initial section mappings in the pgd/pud.
 247          */
 248         BUG_ON(pud_sect(pud));
 249         if (pud_none(pud)) {
 250                 phys_addr_t pmd_phys;
 251                 BUG_ON(!pgtable_alloc);
 252                 pmd_phys = pgtable_alloc(PMD_SHIFT);
 253                 __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE);
 254                 pud = READ_ONCE(*pudp);
 255         }
 256         BUG_ON(pud_bad(pud));
 257
 258         do {
 259                 pgprot_t __prot = prot;
 260
 261                 next = pmd_cont_addr_end(addr, end);
 262
 263                 /* use a contiguous mapping if the range is suitably aligned */
 264                 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
 265                     (flags & NO_CONT_MAPPINGS) == 0)
 266                         __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
 267
 268                 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags);
 269
 270                 phys += next - addr;
 271         } while (addr = next, addr != end);
 272 }
 273
 274 static inline bool use_1G_block(unsigned long addr, unsigned long next,
 275                         unsigned long phys)
 276 {
 277         if (PAGE_SHIFT != 12)
 278                 return false;
 279
 280         if (((addr | next | phys) & ~PUD_MASK) != 0)
 281                 return false;
 282
 283         return true;
 284 }
 285
 286 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
 287                            phys_addr_t phys, pgprot_t prot,
 288                            phys_addr_t (*pgtable_alloc)(int),
 289                            int flags)
 290 {
 291         unsigned long next;
 292         pud_t *pudp;
 293         p4d_t *p4dp = p4d_offset(pgdp, addr);
 294         p4d_t p4d = READ_ONCE(*p4dp);
 295
 296         if (p4d_none(p4d)) {
 297                 phys_addr_t pud_phys;
 298                 BUG_ON(!pgtable_alloc);
 299                 pud_phys = pgtable_alloc(PUD_SHIFT);
 300                 __p4d_populate(p4dp, pud_phys, PUD_TYPE_TABLE);
 301                 p4d = READ_ONCE(*p4dp);
 302         }
 303         BUG_ON(p4d_bad(p4d));
 304
 305         pudp = pud_set_fixmap_offset(p4dp, addr);
 306         do {
 307                 pud_t old_pud = READ_ONCE(*pudp);
 308
 309                 next = pud_addr_end(addr, end);
 310
 311                 /*
 312                  * For 4K granule only, attempt to put down a 1GB block
 313                  */
 314                 if (use_1G_block(addr, next, phys) &&
 315                     (flags & NO_BLOCK_MAPPINGS) == 0) {
 316                         pud_set_huge(pudp, phys, prot);
 317
 318                         /*
 319                          * After the PUD entry has been populated once, we
 320                          * only allow updates to the permission attributes.
 321                          */
 322                         BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
 323                                                       READ_ONCE(pud_val(*pudp))));
 324                 } else {
 325                         alloc_init_cont_pmd(pudp, addr, next, phys, prot,
 326                                             pgtable_alloc, flags);
 327
 328                         BUG_ON(pud_val(old_pud) != 0 &&
 329                                pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
 330                 }
 331                 phys += next - addr;
 332         } while (pudp++, addr = next, addr != end);
 333
 334         pud_clear_fixmap();
 335 }
 336
 337 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 338                                  unsigned long virt, phys_addr_t size,
 339                                  pgprot_t prot,
 340                                  phys_addr_t (*pgtable_alloc)(int),
 341                                  int flags)
 342 {
 343         unsigned long addr, end, next;
 344         pgd_t *pgdp = pgd_offset_pgd(pgdir, virt);
 345
 346         /*
 347          * If the virtual and physical address don't have the same offset
 348          * within a page, we cannot map the region as the caller expects.
 349          */
 350         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
 351                 return;
 352
 353         phys &= PAGE_MASK;
 354         addr = virt & PAGE_MASK;
 355         end = PAGE_ALIGN(virt + size);
 356
 357         do {
 358                 next = pgd_addr_end(addr, end);
 359                 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,
 360                                flags);
 361                 phys += next - addr;
 362         } while (pgdp++, addr = next, addr != end);
 363 }
 364
 365 static phys_addr_t __pgd_pgtable_alloc(int shift)
 366 {
 367         void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
 368         BUG_ON(!ptr);
 369
 370         /* Ensure the zeroed page is visible to the page table walker */
 371         dsb(ishst);
 372         return __pa(ptr);
 373 }
 374
 375 static phys_addr_t pgd_pgtable_alloc(int shift)
 376 {
 377         phys_addr_t pa = __pgd_pgtable_alloc(shift);
 378
 379         /*
 380          * Call proper page table ctor in case later we need to
 381          * call core mm functions like apply_to_page_range() on
 382          * this pre-allocated page table.
 383          *
 384          * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
 385          * folded, and if so pgtable_pmd_page_ctor() becomes nop.
 386          */
 387         if (shift == PAGE_SHIFT)
 388                 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa)));
 389         else if (shift == PMD_SHIFT)
 390                 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa)));
 391
 392         return pa;
 393 }
 394
 395 /*
 396  * This function can only be used to modify existing table entries,
 397  * without allocating new levels of table. Note that this permits the
 398  * creation of new section or page entries.
 399  */
 400 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 401                                   phys_addr_t size, pgprot_t prot)
 402 {
 403         if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
 404                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 405                         &phys, virt);
 406                 return;
 407         }
 408         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
 409                              NO_CONT_MAPPINGS);
 410 }
 411
 412 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 413                                unsigned long virt, phys_addr_t size,
 414                                pgprot_t prot, bool page_mappings_only)
 415 {
 416         int flags = 0;
 417
 418         BUG_ON(mm == &init_mm);
 419
 420         if (page_mappings_only)
 421                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 422
 423         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
 424                              pgd_pgtable_alloc, flags);
 425 }
 426
 427 static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
 428                                 phys_addr_t size, pgprot_t prot)
 429 {
 430         if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
 431                 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
 432                         &phys, virt);
 433                 return;
 434         }
 435
 436         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
 437                              NO_CONT_MAPPINGS);
 438
 439         /* flush the TLBs after updating live kernel mappings */
 440         flush_tlb_kernel_range(virt, virt + size);
 441 }
 442
 443 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
 444                                   phys_addr_t end, pgprot_t prot, int flags)
 445 {
 446         __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start,
 447                              prot, early_pgtable_alloc, flags);
 448 }
 449
 450 void __init mark_linear_text_alias_ro(void)
 451 {
 452         /*
 453          * Remove the write permissions from the linear alias of .text/.rodata
 454          */
 455         update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text),
 456                             (unsigned long)__init_begin - (unsigned long)_text,
 457                             PAGE_KERNEL_RO);
 458 }
 459
 460 static void __init map_mem(pgd_t *pgdp)
 461 {
 462         phys_addr_t kernel_start = __pa_symbol(_text);
 463         phys_addr_t kernel_end = __pa_symbol(__init_begin);
 464         struct memblock_region *reg;
 465         int flags = 0;
 466
 467         if (rodata_full || debug_pagealloc_enabled())
 468                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 469
 470         /*
 471          * Take care not to create a writable alias for the
 472          * read-only text and rodata sections of the kernel image.
 473          * So temporarily mark them as NOMAP to skip mappings in
 474          * the following for-loop
 475          */
 476         memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
 477 #ifdef CONFIG_KEXEC_CORE
 478         if (crashk_res.end)
 479                 memblock_mark_nomap(crashk_res.start,
 480                                     resource_size(&crashk_res));
 481 #endif
 482
 483         /* map all the memory banks */
 484         for_each_memblock(memory, reg) {
 485                 phys_addr_t start = reg->base;
 486                 phys_addr_t end = start + reg->size;
 487
 488                 if (start >= end)
 489                         break;
 490                 if (memblock_is_nomap(reg))
 491                         continue;
 492
 493                 __map_memblock(pgdp, start, end, PAGE_KERNEL, flags);
 494         }
 495
 496         /*
 497          * Map the linear alias of the [_text, __init_begin) interval
 498          * as non-executable now, and remove the write permission in
 499          * mark_linear_text_alias_ro() below (which will be called after
 500          * alternative patching has completed). This makes the contents
 501          * of the region accessible to subsystems such as hibernate,
 502          * but protects it from inadvertent modification or execution.
 503          * Note that contiguous mappings cannot be remapped in this way,
 504          * so we should avoid them here.
 505          */
 506         __map_memblock(pgdp, kernel_start, kernel_end,
 507                        PAGE_KERNEL, NO_CONT_MAPPINGS);
 508         memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
 509
 510 #ifdef CONFIG_KEXEC_CORE
 511         /*
 512          * Use page-level mappings here so that we can shrink the region
 513          * in page granularity and put back unused memory to buddy system
 514          * through /sys/kernel/kexec_crash_size interface.
 515          */
 516         if (crashk_res.end) {
 517                 __map_memblock(pgdp, crashk_res.start, crashk_res.end + 1,
 518                                PAGE_KERNEL,
 519                                NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
 520                 memblock_clear_nomap(crashk_res.start,
 521                                      resource_size(&crashk_res));
 522         }
 523 #endif
 524 }
 525
 526 void mark_rodata_ro(void)
 527 {
 528         unsigned long section_size;
 529
 530         /*
 531          * mark .rodata as read only. Use __init_begin rather than __end_rodata
 532          * to cover NOTES and EXCEPTION_TABLE.
 533          */
 534         section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
 535         update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
 536                             section_size, PAGE_KERNEL_RO);
 537
 538         debug_checkwx();
 539 }
 540
 541 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
 542                                       pgprot_t prot, struct vm_struct *vma,
 543                                       int flags, unsigned long vm_flags)
 544 {
 545         phys_addr_t pa_start = __pa_symbol(va_start);
 546         unsigned long size = va_end - va_start;
 547
 548         BUG_ON(!PAGE_ALIGNED(pa_start));
 549         BUG_ON(!PAGE_ALIGNED(size));
 550
 551         __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot,
 552                              early_pgtable_alloc, flags);
 553
 554         if (!(vm_flags & VM_NO_GUARD))
 555                 size += PAGE_SIZE;
 556
 557         vma->addr       = va_start;
 558         vma->phys_addr  = pa_start;
 559         vma->size       = size;
 560         vma->flags      = VM_MAP | vm_flags;
 561         vma->caller     = __builtin_return_address(0);
 562
 563         vm_area_add_early(vma);
 564 }
 565
 566 static int __init parse_rodata(char *arg)
 567 {
 568         int ret = strtobool(arg, &rodata_enabled);
 569         if (!ret) {
 570                 rodata_full = false;
 571                 return 0;
 572         }
 573
 574         /* permit 'full' in addition to boolean options */
 575         if (strcmp(arg, "full"))
 576                 return -EINVAL;
 577
 578         rodata_enabled = true;
 579         rodata_full = true;
 580         return 0;
 581 }
 582 early_param("rodata", parse_rodata);
 583
 584 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 585 static int __init map_entry_trampoline(void)
 586 {
 587         pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
 588         phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
 589
 590         /* The trampoline is always mapped and can therefore be global */
 591         pgprot_val(prot) &= ~PTE_NG;
 592
 593         /* Map only the text into the trampoline page table */
 594         memset(tramp_pg_dir, 0, PGD_SIZE);
 595         __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
 596                              prot, __pgd_pgtable_alloc, 0);
 597
 598         /* Map both the text and data into the kernel page table */
 599         __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
 600         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 601                 extern char __entry_tramp_data_start[];
 602
 603                 __set_fixmap(FIX_ENTRY_TRAMP_DATA,
 604                              __pa_symbol(__entry_tramp_data_start),
 605                              PAGE_KERNEL_RO);
 606         }
 607
 608         return 0;
 609 }
 610 core_initcall(map_entry_trampoline);
 611 #endif
 612
 613 /*
 614  * Open coded check for BTI, only for use to determine configuration
 615  * for early mappings for before the cpufeature code has run.
 616  */
 617 static bool arm64_early_this_cpu_has_bti(void)
 618 {
 619         u64 pfr1;
 620
 621         if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL))
 622                 return false;
 623
 624         pfr1 = read_sysreg_s(SYS_ID_AA64PFR1_EL1);
 625         return cpuid_feature_extract_unsigned_field(pfr1,
 626                                                     ID_AA64PFR1_BT_SHIFT);
 627 }
 628
 629 /*
 630  * Create fine-grained mappings for the kernel.
 631  */
 632 static void __init map_kernel(pgd_t *pgdp)
 633 {
 634         static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
 635                                 vmlinux_initdata, vmlinux_data;
 636
 637         /*
 638          * External debuggers may need to write directly to the text
 639          * mapping to install SW breakpoints. Allow this (only) when
 640          * explicitly requested with rodata=off.
 641          */
 642         pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
 643
 644         /*
 645          * If we have a CPU that supports BTI and a kernel built for
 646          * BTI then mark the kernel executable text as guarded pages
 647          * now so we don't have to rewrite the page tables later.
 648          */
 649         if (arm64_early_this_cpu_has_bti())
 650                 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP);
 651
 652         /*
 653          * Only rodata will be remapped with different permissions later on,
 654          * all other segments are allowed to use contiguous mappings.
 655          */
 656         map_kernel_segment(pgdp, _text, _etext, text_prot, &vmlinux_text, 0,
 657                            VM_NO_GUARD);
 658         map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL,
 659                            &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD);
 660         map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot,
 661                            &vmlinux_inittext, 0, VM_NO_GUARD);
 662         map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL,
 663                            &vmlinux_initdata, 0, VM_NO_GUARD);
 664         map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
 665
 666         if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) {
 667                 /*
 668                  * The fixmap falls in a separate pgd to the kernel, and doesn't
 669                  * live in the carveout for the swapper_pg_dir. We can simply
 670                  * re-use the existing dir for the fixmap.
 671                  */
 672                 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START),
 673                         READ_ONCE(*pgd_offset_k(FIXADDR_START)));
 674         } else if (CONFIG_PGTABLE_LEVELS > 3) {
 675                 pgd_t *bm_pgdp;
 676                 p4d_t *bm_p4dp;
 677                 pud_t *bm_pudp;
 678                 /*
 679                  * The fixmap shares its top level pgd entry with the kernel
 680                  * mapping. This can really only occur when we are running
 681                  * with 16k/4 levels, so we can simply reuse the pud level
 682                  * entry instead.
 683                  */
 684                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 685                 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START);
 686                 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START);
 687                 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START);
 688                 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
 689                 pud_clear_fixmap();
 690         } else {
 691                 BUG();
 692         }
 693
 694         kasan_copy_shadow(pgdp);
 695 }
 696
 697 void __init paging_init(void)
 698 {
 699         pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir));
 700
 701         map_kernel(pgdp);
 702         map_mem(pgdp);
 703
 704         pgd_clear_fixmap();
 705
 706         cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 707         init_mm.pgd = swapper_pg_dir;
 708
 709         memblock_free(__pa_symbol(init_pg_dir),
 710                       __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir));
 711
 712         memblock_allow_resize();
 713 }
 714
 715 /*
 716  * Check whether a kernel address is valid (derived from arch/x86/).
 717  */
 718 int kern_addr_valid(unsigned long addr)
 719 {
 720         pgd_t *pgdp;
 721         p4d_t *p4dp;
 722         pud_t *pudp, pud;
 723         pmd_t *pmdp, pmd;
 724         pte_t *ptep, pte;
 725
 726         addr = arch_kasan_reset_tag(addr);
 727         if ((((long)addr) >> VA_BITS) != -1UL)
 728                 return 0;
 729
 730         pgdp = pgd_offset_k(addr);
 731         if (pgd_none(READ_ONCE(*pgdp)))
 732                 return 0;
 733
 734         p4dp = p4d_offset(pgdp, addr);
 735         if (p4d_none(READ_ONCE(*p4dp)))
 736                 return 0;
 737
 738         pudp = pud_offset(p4dp, addr);
 739         pud = READ_ONCE(*pudp);
 740         if (pud_none(pud))
 741                 return 0;
 742
 743         if (pud_sect(pud))
 744                 return pfn_valid(pud_pfn(pud));
 745
 746         pmdp = pmd_offset(pudp, addr);
 747         pmd = READ_ONCE(*pmdp);
 748         if (pmd_none(pmd))
 749                 return 0;
 750
 751         if (pmd_sect(pmd))
 752                 return pfn_valid(pmd_pfn(pmd));
 753
 754         ptep = pte_offset_kernel(pmdp, addr);
 755         pte = READ_ONCE(*ptep);
 756         if (pte_none(pte))
 757                 return 0;
 758
 759         return pfn_valid(pte_pfn(pte));
 760 }
 761
 762 #ifdef CONFIG_MEMORY_HOTPLUG
 763 static void free_hotplug_page_range(struct page *page, size_t size)
 764 {
 765         WARN_ON(PageReserved(page));
 766         free_pages((unsigned long)page_address(page), get_order(size));
 767 }
 768
 769 static void free_hotplug_pgtable_page(struct page *page)
 770 {
 771         free_hotplug_page_range(page, PAGE_SIZE);
 772 }
 773
 774 static bool pgtable_range_aligned(unsigned long start, unsigned long end,
 775                                   unsigned long floor, unsigned long ceiling,
 776                                   unsigned long mask)
 777 {
 778         start &= mask;
 779         if (start < floor)
 780                 return false;
 781
 782         if (ceiling) {
 783                 ceiling &= mask;
 784                 if (!ceiling)
 785                         return false;
 786         }
 787
 788         if (end - 1 > ceiling - 1)
 789                 return false;
 790         return true;
 791 }
 792
 793 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr,
 794                                     unsigned long end, bool free_mapped)
 795 {
 796         pte_t *ptep, pte;
 797
 798         do {
 799                 ptep = pte_offset_kernel(pmdp, addr);
 800                 pte = READ_ONCE(*ptep);
 801                 if (pte_none(pte))
 802                         continue;
 803
 804                 WARN_ON(!pte_present(pte));
 805                 pte_clear(&init_mm, addr, ptep);
 806                 flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 807                 if (free_mapped)
 808                         free_hotplug_page_range(pte_page(pte), PAGE_SIZE);
 809         } while (addr += PAGE_SIZE, addr < end);
 810 }
 811
 812 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr,
 813                                     unsigned long end, bool free_mapped)
 814 {
 815         unsigned long next;
 816         pmd_t *pmdp, pmd;
 817
 818         do {
 819                 next = pmd_addr_end(addr, end);
 820                 pmdp = pmd_offset(pudp, addr);
 821                 pmd = READ_ONCE(*pmdp);
 822                 if (pmd_none(pmd))
 823                         continue;
 824
 825                 WARN_ON(!pmd_present(pmd));
 826                 if (pmd_sect(pmd)) {
 827                         pmd_clear(pmdp);
 828
 829                         /*
 830                          * One TLBI should be sufficient here as the PMD_SIZE
 831                          * range is mapped with a single block entry.
 832                          */
 833                         flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 834                         if (free_mapped)
 835                                 free_hotplug_page_range(pmd_page(pmd),
 836                                                         PMD_SIZE);
 837                         continue;
 838                 }
 839                 WARN_ON(!pmd_table(pmd));
 840                 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped);
 841         } while (addr = next, addr < end);
 842 }
 843
 844 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr,
 845                                     unsigned long end, bool free_mapped)
 846 {
 847         unsigned long next;
 848         pud_t *pudp, pud;
 849
 850         do {
 851                 next = pud_addr_end(addr, end);
 852                 pudp = pud_offset(p4dp, addr);
 853                 pud = READ_ONCE(*pudp);
 854                 if (pud_none(pud))
 855                         continue;
 856
 857                 WARN_ON(!pud_present(pud));
 858                 if (pud_sect(pud)) {
 859                         pud_clear(pudp);
 860
 861                         /*
 862                          * One TLBI should be sufficient here as the PUD_SIZE
 863                          * range is mapped with a single block entry.
 864                          */
 865                         flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
 866                         if (free_mapped)
 867                                 free_hotplug_page_range(pud_page(pud),
 868                                                         PUD_SIZE);
 869                         continue;
 870                 }
 871                 WARN_ON(!pud_table(pud));
 872                 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped);
 873         } while (addr = next, addr < end);
 874 }
 875
 876 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr,
 877                                     unsigned long end, bool free_mapped)
 878 {
 879         unsigned long next;
 880         p4d_t *p4dp, p4d;
 881
 882         do {
 883                 next = p4d_addr_end(addr, end);
 884                 p4dp = p4d_offset(pgdp, addr);
 885                 p4d = READ_ONCE(*p4dp);
 886                 if (p4d_none(p4d))
 887                         continue;
 888
 889                 WARN_ON(!p4d_present(p4d));
 890                 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped);
 891         } while (addr = next, addr < end);
 892 }
 893
 894 static void unmap_hotplug_range(unsigned long addr, unsigned long end,
 895                                 bool free_mapped)
 896 {
 897         unsigned long next;
 898         pgd_t *pgdp, pgd;
 899
 900         do {
 901                 next = pgd_addr_end(addr, end);
 902                 pgdp = pgd_offset_k(addr);
 903                 pgd = READ_ONCE(*pgdp);
 904                 if (pgd_none(pgd))
 905                         continue;
 906
 907                 WARN_ON(!pgd_present(pgd));
 908                 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped);
 909         } while (addr = next, addr < end);
 910 }
 911
 912 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr,
 913                                  unsigned long end, unsigned long floor,
 914                                  unsigned long ceiling)
 915 {
 916         pte_t *ptep, pte;
 917         unsigned long i, start = addr;
 918
 919         do {
 920                 ptep = pte_offset_kernel(pmdp, addr);
 921                 pte = READ_ONCE(*ptep);
 922
 923                 /*
 924                  * This is just a sanity check here which verifies that
 925                  * pte clearing has been done by earlier unmap loops.
 926                  */
 927                 WARN_ON(!pte_none(pte));
 928         } while (addr += PAGE_SIZE, addr < end);
 929
 930         if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK))
 931                 return;
 932
 933         /*
 934          * Check whether we can free the pte page if the rest of the
 935          * entries are empty. Overlap with other regions have been
 936          * handled by the floor/ceiling check.
 937          */
 938         ptep = pte_offset_kernel(pmdp, 0UL);
 939         for (i = 0; i < PTRS_PER_PTE; i++) {
 940                 if (!pte_none(READ_ONCE(ptep[i])))
 941                         return;
 942         }
 943
 944         pmd_clear(pmdp);
 945         __flush_tlb_kernel_pgtable(start);
 946         free_hotplug_pgtable_page(virt_to_page(ptep));
 947 }
 948
 949 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr,
 950                                  unsigned long end, unsigned long floor,
 951                                  unsigned long ceiling)
 952 {
 953         pmd_t *pmdp, pmd;
 954         unsigned long i, next, start = addr;
 955
 956         do {
 957                 next = pmd_addr_end(addr, end);
 958                 pmdp = pmd_offset(pudp, addr);
 959                 pmd = READ_ONCE(*pmdp);
 960                 if (pmd_none(pmd))
 961                         continue;
 962
 963                 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd));
 964                 free_empty_pte_table(pmdp, addr, next, floor, ceiling);
 965         } while (addr = next, addr < end);
 966
 967         if (CONFIG_PGTABLE_LEVELS <= 2)
 968                 return;
 969
 970         if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK))
 971                 return;
 972
 973         /*
 974          * Check whether we can free the pmd page if the rest of the
 975          * entries are empty. Overlap with other regions have been
 976          * handled by the floor/ceiling check.
 977          */
 978         pmdp = pmd_offset(pudp, 0UL);
 979         for (i = 0; i < PTRS_PER_PMD; i++) {
 980                 if (!pmd_none(READ_ONCE(pmdp[i])))
 981                         return;
 982         }
 983
 984         pud_clear(pudp);
 985         __flush_tlb_kernel_pgtable(start);
 986         free_hotplug_pgtable_page(virt_to_page(pmdp));
 987 }
 988
 989 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr,
 990                                  unsigned long end, unsigned long floor,
 991                                  unsigned long ceiling)
 992 {
 993         pud_t *pudp, pud;
 994         unsigned long i, next, start = addr;
 995
 996         do {
 997                 next = pud_addr_end(addr, end);
 998                 pudp = pud_offset(p4dp, addr);
 999                 pud = READ_ONCE(*pudp);
1000                 if (pud_none(pud))
1001                         continue;
1002
1003                 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud));
1004                 free_empty_pmd_table(pudp, addr, next, floor, ceiling);
1005         } while (addr = next, addr < end);
1006
1007         if (CONFIG_PGTABLE_LEVELS <= 3)
1008                 return;
1009
1010         if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK))
1011                 return;
1012
1013         /*
1014          * Check whether we can free the pud page if the rest of the
1015          * entries are empty. Overlap with other regions have been
1016          * handled by the floor/ceiling check.
1017          */
1018         pudp = pud_offset(p4dp, 0UL);
1019         for (i = 0; i < PTRS_PER_PUD; i++) {
1020                 if (!pud_none(READ_ONCE(pudp[i])))
1021                         return;
1022         }
1023
1024         p4d_clear(p4dp);
1025         __flush_tlb_kernel_pgtable(start);
1026         free_hotplug_pgtable_page(virt_to_page(pudp));
1027 }
1028
1029 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr,
1030                                  unsigned long end, unsigned long floor,
1031                                  unsigned long ceiling)
1032 {
1033         unsigned long next;
1034         p4d_t *p4dp, p4d;
1035
1036         do {
1037                 next = p4d_addr_end(addr, end);
1038                 p4dp = p4d_offset(pgdp, addr);
1039                 p4d = READ_ONCE(*p4dp);
1040                 if (p4d_none(p4d))
1041                         continue;
1042
1043                 WARN_ON(!p4d_present(p4d));
1044                 free_empty_pud_table(p4dp, addr, next, floor, ceiling);
1045         } while (addr = next, addr < end);
1046 }
1047
1048 static void free_empty_tables(unsigned long addr, unsigned long end,
1049                               unsigned long floor, unsigned long ceiling)
1050 {
1051         unsigned long next;
1052         pgd_t *pgdp, pgd;
1053
1054         do {
1055                 next = pgd_addr_end(addr, end);
1056                 pgdp = pgd_offset_k(addr);
1057                 pgd = READ_ONCE(*pgdp);
1058                 if (pgd_none(pgd))
1059                         continue;
1060
1061                 WARN_ON(!pgd_present(pgd));
1062                 free_empty_p4d_table(pgdp, addr, next, floor, ceiling);
1063         } while (addr = next, addr < end);
1064 }
1065 #endif
1066
1067 #ifdef CONFIG_SPARSEMEM_VMEMMAP
1068 #if !ARM64_SWAPPER_USES_SECTION_MAPS
1069 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
1070                 struct vmem_altmap *altmap)
1071 {
1072         return vmemmap_populate_basepages(start, end, node);
1073 }
1074 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
1075 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
1076                 struct vmem_altmap *altmap)
1077 {
1078         unsigned long addr = start;
1079         unsigned long next;
1080         pgd_t *pgdp;
1081         p4d_t *p4dp;
1082         pud_t *pudp;
1083         pmd_t *pmdp;
1084
1085         do {
1086                 next = pmd_addr_end(addr, end);
1087
1088                 pgdp = vmemmap_pgd_populate(addr, node);
1089                 if (!pgdp)
1090                         return -ENOMEM;
1091
1092                 p4dp = vmemmap_p4d_populate(pgdp, addr, node);
1093                 if (!p4dp)
1094                         return -ENOMEM;
1095
1096                 pudp = vmemmap_pud_populate(p4dp, addr, node);
1097                 if (!pudp)
1098                         return -ENOMEM;
1099
1100                 pmdp = pmd_offset(pudp, addr);
1101                 if (pmd_none(READ_ONCE(*pmdp))) {
1102                         void *p = NULL;
1103
1104                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
1105                         if (!p)
1106                                 return -ENOMEM;
1107
1108                         pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
1109                 } else
1110                         vmemmap_verify((pte_t *)pmdp, node, addr, next);
1111         } while (addr = next, addr != end);
1112
1113         return 0;
1114 }
1115 #endif  /* !ARM64_SWAPPER_USES_SECTION_MAPS */
1116 void vmemmap_free(unsigned long start, unsigned long end,
1117                 struct vmem_altmap *altmap)
1118 {
1119 #ifdef CONFIG_MEMORY_HOTPLUG
1120         WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END));
1121
1122         unmap_hotplug_range(start, end, true);
1123         free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END);
1124 #endif
1125 }
1126 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
1127
1128 static inline pud_t * fixmap_pud(unsigned long addr)
1129 {
1130         pgd_t *pgdp = pgd_offset_k(addr);
1131         p4d_t *p4dp = p4d_offset(pgdp, addr);
1132         p4d_t p4d = READ_ONCE(*p4dp);
1133
1134         BUG_ON(p4d_none(p4d) || p4d_bad(p4d));
1135
1136         return pud_offset_kimg(p4dp, addr);
1137 }
1138
1139 static inline pmd_t * fixmap_pmd(unsigned long addr)
1140 {
1141         pud_t *pudp = fixmap_pud(addr);
1142         pud_t pud = READ_ONCE(*pudp);
1143
1144         BUG_ON(pud_none(pud) || pud_bad(pud));
1145
1146         return pmd_offset_kimg(pudp, addr);
1147 }
1148
1149 static inline pte_t * fixmap_pte(unsigned long addr)
1150 {
1151         return &bm_pte[pte_index(addr)];
1152 }
1153
1154 /*
1155  * The p*d_populate functions call virt_to_phys implicitly so they can't be used
1156  * directly on kernel symbols (bm_p*d). This function is called too early to use
1157  * lm_alias so __p*d_populate functions must be used to populate with the
1158  * physical address from __pa_symbol.
1159  */
1160 void __init early_fixmap_init(void)
1161 {
1162         pgd_t *pgdp;
1163         p4d_t *p4dp, p4d;
1164         pud_t *pudp;
1165         pmd_t *pmdp;
1166         unsigned long addr = FIXADDR_START;
1167
1168         pgdp = pgd_offset_k(addr);
1169         p4dp = p4d_offset(pgdp, addr);
1170         p4d = READ_ONCE(*p4dp);
1171         if (CONFIG_PGTABLE_LEVELS > 3 &&
1172             !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) {
1173                 /*
1174                  * We only end up here if the kernel mapping and the fixmap
1175                  * share the top level pgd entry, which should only happen on
1176                  * 16k/4 levels configurations.
1177                  */
1178                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
1179                 pudp = pud_offset_kimg(p4dp, addr);
1180         } else {
1181                 if (p4d_none(p4d))
1182                         __p4d_populate(p4dp, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
1183                 pudp = fixmap_pud(addr);
1184         }
1185         if (pud_none(READ_ONCE(*pudp)))
1186                 __pud_populate(pudp, __pa_symbol(bm_pmd), PMD_TYPE_TABLE);
1187         pmdp = fixmap_pmd(addr);
1188         __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
1189
1190         /*
1191          * The boot-ioremap range spans multiple pmds, for which
1192          * we are not prepared:
1193          */
1194         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
1195                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
1196
1197         if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
1198              || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
1199                 WARN_ON(1);
1200                 pr_warn("pmdp %p != %p, %p\n",
1201                         pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
1202                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
1203                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
1204                         fix_to_virt(FIX_BTMAP_BEGIN));
1205                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
1206                         fix_to_virt(FIX_BTMAP_END));
1207
1208                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
1209                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
1210         }
1211 }
1212
1213 /*
1214  * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
1215  * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
1216  */
1217 void __set_fixmap(enum fixed_addresses idx,
1218                                phys_addr_t phys, pgprot_t flags)
1219 {
1220         unsigned long addr = __fix_to_virt(idx);
1221         pte_t *ptep;
1222
1223         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
1224
1225         ptep = fixmap_pte(addr);
1226
1227         if (pgprot_val(flags)) {
1228                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
1229         } else {
1230                 pte_clear(&init_mm, addr, ptep);
1231                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
1232         }
1233 }
1234
1235 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
1236 {
1237         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
1238         int offset;
1239         void *dt_virt;
1240
1241         /*
1242          * Check whether the physical FDT address is set and meets the minimum
1243          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
1244          * at least 8 bytes so that we can always access the magic and size
1245          * fields of the FDT header after mapping the first chunk, double check
1246          * here if that is indeed the case.
1247          */
1248         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
1249         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
1250                 return NULL;
1251
1252         /*
1253          * Make sure that the FDT region can be mapped without the need to
1254          * allocate additional translation table pages, so that it is safe
1255          * to call create_mapping_noalloc() this early.
1256          *
1257          * On 64k pages, the FDT will be mapped using PTEs, so we need to
1258          * be in the same PMD as the rest of the fixmap.
1259          * On 4k pages, we'll use section mappings for the FDT so we only
1260          * have to be in the same PUD.
1261          */
1262         BUILD_BUG_ON(dt_virt_base % SZ_2M);
1263
1264         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
1265                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
1266
1267         offset = dt_phys % SWAPPER_BLOCK_SIZE;
1268         dt_virt = (void *)dt_virt_base + offset;
1269
1270         /* map the first chunk so we can read the size from the header */
1271         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
1272                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
1273
1274         if (fdt_magic(dt_virt) != FDT_MAGIC)
1275                 return NULL;
1276
1277         *size = fdt_totalsize(dt_virt);
1278         if (*size > MAX_FDT_SIZE)
1279                 return NULL;
1280
1281         if (offset + *size > SWAPPER_BLOCK_SIZE)
1282                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
1283                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
1284
1285         return dt_virt;
1286 }
1287
1288 int __init arch_ioremap_p4d_supported(void)
1289 {
1290         return 0;
1291 }
1292
1293 int __init arch_ioremap_pud_supported(void)
1294 {
1295         /*
1296          * Only 4k granule supports level 1 block mappings.
1297          * SW table walks can't handle removal of intermediate entries.
1298          */
1299         return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
1300                !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
1301 }
1302
1303 int __init arch_ioremap_pmd_supported(void)
1304 {
1305         /* See arch_ioremap_pud_supported() */
1306         return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
1307 }
1308
1309 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
1310 {
1311         pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
1312
1313         /* Only allow permission changes for now */
1314         if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)),
1315                                    pud_val(new_pud)))
1316                 return 0;
1317
1318         VM_BUG_ON(phys & ~PUD_MASK);
1319         set_pud(pudp, new_pud);
1320         return 1;
1321 }
1322
1323 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
1324 {
1325         pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));
1326
1327         /* Only allow permission changes for now */
1328         if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)),
1329                                    pmd_val(new_pmd)))
1330                 return 0;
1331
1332         VM_BUG_ON(phys & ~PMD_MASK);
1333         set_pmd(pmdp, new_pmd);
1334         return 1;
1335 }
1336
1337 int pud_clear_huge(pud_t *pudp)
1338 {
1339         if (!pud_sect(READ_ONCE(*pudp)))
1340                 return 0;
1341         pud_clear(pudp);
1342         return 1;
1343 }
1344
1345 int pmd_clear_huge(pmd_t *pmdp)
1346 {
1347         if (!pmd_sect(READ_ONCE(*pmdp)))
1348                 return 0;
1349         pmd_clear(pmdp);
1350         return 1;
1351 }
1352
1353 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
1354 {
1355         pte_t *table;
1356         pmd_t pmd;
1357
1358         pmd = READ_ONCE(*pmdp);
1359
1360         if (!pmd_table(pmd)) {
1361                 VM_WARN_ON(1);
1362                 return 1;
1363         }
1364
1365         table = pte_offset_kernel(pmdp, addr);
1366         pmd_clear(pmdp);
1367         __flush_tlb_kernel_pgtable(addr);
1368         pte_free_kernel(NULL, table);
1369         return 1;
1370 }
1371
1372 int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
1373 {
1374         pmd_t *table;
1375         pmd_t *pmdp;
1376         pud_t pud;
1377         unsigned long next, end;
1378
1379         pud = READ_ONCE(*pudp);
1380
1381         if (!pud_table(pud)) {
1382                 VM_WARN_ON(1);
1383                 return 1;
1384         }
1385
1386         table = pmd_offset(pudp, addr);
1387         pmdp = table;
1388         next = addr;
1389         end = addr + PUD_SIZE;
1390         do {
1391                 pmd_free_pte_page(pmdp, next);
1392         } while (pmdp++, next += PMD_SIZE, next != end);
1393
1394         pud_clear(pudp);
1395         __flush_tlb_kernel_pgtable(addr);
1396         pmd_free(NULL, table);
1397         return 1;
1398 }
1399
1400 int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
1401 {
1402         return 0;       /* Don't attempt a block mapping */
1403 }
1404
1405 #ifdef CONFIG_MEMORY_HOTPLUG
1406 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size)
1407 {
1408         unsigned long end = start + size;
1409
1410         WARN_ON(pgdir != init_mm.pgd);
1411         WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END));
1412
1413         unmap_hotplug_range(start, end, false);
1414         free_empty_tables(start, end, PAGE_OFFSET, PAGE_END);
1415 }
1416
1417 int arch_add_memory(int nid, u64 start, u64 size,
1418                     struct mhp_params *params)
1419 {
1420         int ret, flags = 0;
1421
1422         if (rodata_full || debug_pagealloc_enabled())
1423                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
1424
1425         __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
1426                              size, params->pgprot, __pgd_pgtable_alloc,
1427                              flags);
1428
1429         memblock_clear_nomap(start, size);
1430
1431         ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
1432                            params);
1433         if (ret)
1434                 __remove_pgd_mapping(swapper_pg_dir,
1435                                      __phys_to_virt(start), size);
1436         return ret;
1437 }
1438
1439 void arch_remove_memory(int nid, u64 start, u64 size,
1440                         struct vmem_altmap *altmap)
1441 {
1442         unsigned long start_pfn = start >> PAGE_SHIFT;
1443         unsigned long nr_pages = size >> PAGE_SHIFT;
1444
1445         __remove_pages(start_pfn, nr_pages, altmap);
1446         __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size);
1447 }
1448
1449 /*
1450  * This memory hotplug notifier helps prevent boot memory from being
1451  * inadvertently removed as it blocks pfn range offlining process in
1452  * __offline_pages(). Hence this prevents both offlining as well as
1453  * removal process for boot memory which is initially always online.
1454  * In future if and when boot memory could be removed, this notifier
1455  * should be dropped and free_hotplug_page_range() should handle any
1456  * reserved pages allocated during boot.
1457  */
1458 static int prevent_bootmem_remove_notifier(struct notifier_block *nb,
1459                                            unsigned long action, void *data)
1460 {
1461         struct mem_section *ms;
1462         struct memory_notify *arg = data;
1463         unsigned long end_pfn = arg->start_pfn + arg->nr_pages;
1464         unsigned long pfn = arg->start_pfn;
1465
1466         if (action != MEM_GOING_OFFLINE)
1467                 return NOTIFY_OK;
1468
1469         for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
1470                 ms = __pfn_to_section(pfn);
1471                 if (early_section(ms))
1472                         return NOTIFY_BAD;
1473         }
1474         return NOTIFY_OK;
1475 }
1476
1477 static struct notifier_block prevent_bootmem_remove_nb = {
1478         .notifier_call = prevent_bootmem_remove_notifier,
1479 };
1480
1481 static int __init prevent_bootmem_remove_init(void)
1482 {
1483         return register_memory_notifier(&prevent_bootmem_remove_nb);
1484 }
1485 device_initcall(prevent_bootmem_remove_init);
1486 #endif