arch/arm64/mm/mmu.c

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This source file includes following definitions.
__section
phys_mem_access_prot
early_pgtable_alloc
pgattr_change_is_safe
init_pte
alloc_init_cont_pte
init_pmd
alloc_init_cont_pmd
use_1G_block
alloc_init_pud
__create_pgd_mapping
__pgd_pgtable_alloc
pgd_pgtable_alloc
create_mapping_noalloc
create_pgd_mapping
update_mapping_prot
__map_memblock
mark_linear_text_alias_ro
map_mem
mark_rodata_ro
map_kernel_segment
parse_rodata
map_entry_trampoline
map_kernel
paging_init
kern_addr_valid
vmemmap_populate
vmemmap_populate
vmemmap_free
fixmap_pud
fixmap_pmd
fixmap_pte
early_fixmap_init
__set_fixmap
fixmap_remap_fdt
arch_ioremap_p4d_supported
arch_ioremap_pud_supported
arch_ioremap_pmd_supported
pud_set_huge
pmd_set_huge
pud_clear_huge
pmd_clear_huge
pmd_free_pte_page
pud_free_pmd_page
p4d_free_pud_page
arch_add_memory
arch_remove_memory
   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/fs.h>
  21 #include <linux/io.h>
  22 #include <linux/mm.h>
  23 #include <linux/vmalloc.h>
  24 
  25 #include <asm/barrier.h>
  26 #include <asm/cputype.h>
  27 #include <asm/fixmap.h>
  28 #include <asm/kasan.h>
  29 #include <asm/kernel-pgtable.h>
  30 #include <asm/sections.h>
  31 #include <asm/setup.h>
  32 #include <linux/sizes.h>
  33 #include <asm/tlb.h>
  34 #include <asm/mmu_context.h>
  35 #include <asm/ptdump.h>
  36 #include <asm/tlbflush.h>
  37 
  38 #define NO_BLOCK_MAPPINGS       BIT(0)
  39 #define NO_CONT_MAPPINGS        BIT(1)
  40 
  41 u64 idmap_t0sz = TCR_T0SZ(VA_BITS);
  42 u64 idmap_ptrs_per_pgd = PTRS_PER_PGD;
  43 
  44 u64 __section(".mmuoff.data.write") vabits_actual;
  45 EXPORT_SYMBOL(vabits_actual);
  46 
  47 u64 kimage_voffset __ro_after_init;
  48 EXPORT_SYMBOL(kimage_voffset);
  49 
  50 /*
  51  * Empty_zero_page is a special page that is used for zero-initialized data
  52  * and COW.
  53  */
  54 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss;
  55 EXPORT_SYMBOL(empty_zero_page);
  56 
  57 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss;
  58 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused;
  59 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused;
  60 
  61 static DEFINE_SPINLOCK(swapper_pgdir_lock);
  62 
  63 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd)
  64 {
  65         pgd_t *fixmap_pgdp;
  66 
  67         spin_lock(&swapper_pgdir_lock);
  68         fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp));
  69         WRITE_ONCE(*fixmap_pgdp, pgd);
  70         /*
  71          * We need dsb(ishst) here to ensure the page-table-walker sees
  72          * our new entry before set_p?d() returns. The fixmap's
  73          * flush_tlb_kernel_range() via clear_fixmap() does this for us.
  74          */
  75         pgd_clear_fixmap();
  76         spin_unlock(&swapper_pgdir_lock);
  77 }
  78 
  79 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
  80                               unsigned long size, pgprot_t vma_prot)
  81 {
  82         if (!pfn_valid(pfn))
  83                 return pgprot_noncached(vma_prot);
  84         else if (file->f_flags & O_SYNC)
  85                 return pgprot_writecombine(vma_prot);
  86         return vma_prot;
  87 }
  88 EXPORT_SYMBOL(phys_mem_access_prot);
  89 
  90 static phys_addr_t __init early_pgtable_alloc(int shift)
  91 {
  92         phys_addr_t phys;
  93         void *ptr;
  94 
  95         phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
  96         if (!phys)
  97                 panic("Failed to allocate page table page\n");
  98 
  99         /*
 100          * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE
 101          * slot will be free, so we can (ab)use the FIX_PTE slot to initialise
 102          * any level of table.
 103          */
 104         ptr = pte_set_fixmap(phys);
 105 
 106         memset(ptr, 0, PAGE_SIZE);
 107 
 108         /*
 109          * Implicit barriers also ensure the zeroed page is visible to the page
 110          * table walker
 111          */
 112         pte_clear_fixmap();
 113 
 114         return phys;
 115 }
 116 
 117 static bool pgattr_change_is_safe(u64 old, u64 new)
 118 {
 119         /*
 120          * The following mapping attributes may be updated in live
 121          * kernel mappings without the need for break-before-make.
 122          */
 123         static const pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG;
 124 
 125         /* creating or taking down mappings is always safe */
 126         if (old == 0 || new == 0)
 127                 return true;
 128 
 129         /* live contiguous mappings may not be manipulated at all */
 130         if ((old | new) & PTE_CONT)
 131                 return false;
 132 
 133         /* Transitioning from Non-Global to Global is unsafe */
 134         if (old & ~new & PTE_NG)
 135                 return false;
 136 
 137         return ((old ^ new) & ~mask) == 0;
 138 }
 139 
 140 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
 141                      phys_addr_t phys, pgprot_t prot)
 142 {
 143         pte_t *ptep;
 144 
 145         ptep = pte_set_fixmap_offset(pmdp, addr);
 146         do {
 147                 pte_t old_pte = READ_ONCE(*ptep);
 148 
 149                 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot));
 150 
 151                 /*
 152                  * After the PTE entry has been populated once, we
 153                  * only allow updates to the permission attributes.
 154                  */
 155                 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
 156                                               READ_ONCE(pte_val(*ptep))));
 157 
 158                 phys += PAGE_SIZE;
 159         } while (ptep++, addr += PAGE_SIZE, addr != end);
 160 
 161         pte_clear_fixmap();
 162 }
 163 
 164 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
 165                                 unsigned long end, phys_addr_t phys,
 166                                 pgprot_t prot,
 167                                 phys_addr_t (*pgtable_alloc)(int),
 168                                 int flags)
 169 {
 170         unsigned long next;
 171         pmd_t pmd = READ_ONCE(*pmdp);
 172 
 173         BUG_ON(pmd_sect(pmd));
 174         if (pmd_none(pmd)) {
 175                 phys_addr_t pte_phys;
 176                 BUG_ON(!pgtable_alloc);
 177                 pte_phys = pgtable_alloc(PAGE_SHIFT);
 178                 __pmd_populate(pmdp, pte_phys, PMD_TYPE_TABLE);
 179                 pmd = READ_ONCE(*pmdp);
 180         }
 181         BUG_ON(pmd_bad(pmd));
 182 
 183         do {
 184                 pgprot_t __prot = prot;
 185 
 186                 next = pte_cont_addr_end(addr, end);
 187 
 188                 /* use a contiguous mapping if the range is suitably aligned */
 189                 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) &&
 190                     (flags & NO_CONT_MAPPINGS) == 0)
 191                         __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
 192 
 193                 init_pte(pmdp, addr, next, phys, __prot);
 194 
 195                 phys += next - addr;
 196         } while (addr = next, addr != end);
 197 }
 198 
 199 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
 200                      phys_addr_t phys, pgprot_t prot,
 201                      phys_addr_t (*pgtable_alloc)(int), int flags)
 202 {
 203         unsigned long next;
 204         pmd_t *pmdp;
 205 
 206         pmdp = pmd_set_fixmap_offset(pudp, addr);
 207         do {
 208                 pmd_t old_pmd = READ_ONCE(*pmdp);
 209 
 210                 next = pmd_addr_end(addr, end);
 211 
 212                 /* try section mapping first */
 213                 if (((addr | next | phys) & ~SECTION_MASK) == 0 &&
 214                     (flags & NO_BLOCK_MAPPINGS) == 0) {
 215                         pmd_set_huge(pmdp, phys, prot);
 216 
 217                         /*
 218                          * After the PMD entry has been populated once, we
 219                          * only allow updates to the permission attributes.
 220                          */
 221                         BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
 222                                                       READ_ONCE(pmd_val(*pmdp))));
 223                 } else {
 224                         alloc_init_cont_pte(pmdp, addr, next, phys, prot,
 225                                             pgtable_alloc, flags);
 226 
 227                         BUG_ON(pmd_val(old_pmd) != 0 &&
 228                                pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
 229                 }
 230                 phys += next - addr;
 231         } while (pmdp++, addr = next, addr != end);
 232 
 233         pmd_clear_fixmap();
 234 }
 235 
 236 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
 237                                 unsigned long end, phys_addr_t phys,
 238                                 pgprot_t prot,
 239                                 phys_addr_t (*pgtable_alloc)(int), int flags)
 240 {
 241         unsigned long next;
 242         pud_t pud = READ_ONCE(*pudp);
 243 
 244         /*
 245          * Check for initial section mappings in the pgd/pud.
 246          */
 247         BUG_ON(pud_sect(pud));
 248         if (pud_none(pud)) {
 249                 phys_addr_t pmd_phys;
 250                 BUG_ON(!pgtable_alloc);
 251                 pmd_phys = pgtable_alloc(PMD_SHIFT);
 252                 __pud_populate(pudp, pmd_phys, PUD_TYPE_TABLE);
 253                 pud = READ_ONCE(*pudp);
 254         }
 255         BUG_ON(pud_bad(pud));
 256 
 257         do {
 258                 pgprot_t __prot = prot;
 259 
 260                 next = pmd_cont_addr_end(addr, end);
 261 
 262                 /* use a contiguous mapping if the range is suitably aligned */
 263                 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) &&
 264                     (flags & NO_CONT_MAPPINGS) == 0)
 265                         __prot = __pgprot(pgprot_val(prot) | PTE_CONT);
 266 
 267                 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags);
 268 
 269                 phys += next - addr;
 270         } while (addr = next, addr != end);
 271 }
 272 
 273 static inline bool use_1G_block(unsigned long addr, unsigned long next,
 274                         unsigned long phys)
 275 {
 276         if (PAGE_SHIFT != 12)
 277                 return false;
 278 
 279         if (((addr | next | phys) & ~PUD_MASK) != 0)
 280                 return false;
 281 
 282         return true;
 283 }
 284 
 285 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
 286                            phys_addr_t phys, pgprot_t prot,
 287                            phys_addr_t (*pgtable_alloc)(int),
 288                            int flags)
 289 {
 290         unsigned long next;
 291         pud_t *pudp;
 292         pgd_t pgd = READ_ONCE(*pgdp);
 293 
 294         if (pgd_none(pgd)) {
 295                 phys_addr_t pud_phys;
 296                 BUG_ON(!pgtable_alloc);
 297                 pud_phys = pgtable_alloc(PUD_SHIFT);
 298                 __pgd_populate(pgdp, pud_phys, PUD_TYPE_TABLE);
 299                 pgd = READ_ONCE(*pgdp);
 300         }
 301         BUG_ON(pgd_bad(pgd));
 302 
 303         pudp = pud_set_fixmap_offset(pgdp, addr);
 304         do {
 305                 pud_t old_pud = READ_ONCE(*pudp);
 306 
 307                 next = pud_addr_end(addr, end);
 308 
 309                 /*
 310                  * For 4K granule only, attempt to put down a 1GB block
 311                  */
 312                 if (use_1G_block(addr, next, phys) &&
 313                     (flags & NO_BLOCK_MAPPINGS) == 0) {
 314                         pud_set_huge(pudp, phys, prot);
 315 
 316                         /*
 317                          * After the PUD entry has been populated once, we
 318                          * only allow updates to the permission attributes.
 319                          */
 320                         BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
 321                                                       READ_ONCE(pud_val(*pudp))));
 322                 } else {
 323                         alloc_init_cont_pmd(pudp, addr, next, phys, prot,
 324                                             pgtable_alloc, flags);
 325 
 326                         BUG_ON(pud_val(old_pud) != 0 &&
 327                                pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
 328                 }
 329                 phys += next - addr;
 330         } while (pudp++, addr = next, addr != end);
 331 
 332         pud_clear_fixmap();
 333 }
 334 
 335 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 336                                  unsigned long virt, phys_addr_t size,
 337                                  pgprot_t prot,
 338                                  phys_addr_t (*pgtable_alloc)(int),
 339                                  int flags)
 340 {
 341         unsigned long addr, length, end, next;
 342         pgd_t *pgdp = pgd_offset_raw(pgdir, virt);
 343 
 344         /*
 345          * If the virtual and physical address don't have the same offset
 346          * within a page, we cannot map the region as the caller expects.
 347          */
 348         if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
 349                 return;
 350 
 351         phys &= PAGE_MASK;
 352         addr = virt & PAGE_MASK;
 353         length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
 354 
 355         end = addr + length;
 356         do {
 357                 next = pgd_addr_end(addr, end);
 358                 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,
 359                                flags);
 360                 phys += next - addr;
 361         } while (pgdp++, addr = next, addr != end);
 362 }
 363 
 364 static phys_addr_t __pgd_pgtable_alloc(int shift)
 365 {
 366         void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL);
 367         BUG_ON(!ptr);
 368 
 369         /* Ensure the zeroed page is visible to the page table walker */
 370         dsb(ishst);
 371         return __pa(ptr);
 372 }
 373 
 374 static phys_addr_t pgd_pgtable_alloc(int shift)
 375 {
 376         phys_addr_t pa = __pgd_pgtable_alloc(shift);
 377 
 378         /*
 379          * Call proper page table ctor in case later we need to
 380          * call core mm functions like apply_to_page_range() on
 381          * this pre-allocated page table.
 382          *
 383          * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is
 384          * folded, and if so pgtable_pmd_page_ctor() becomes nop.
 385          */
 386         if (shift == PAGE_SHIFT)
 387                 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa)));
 388         else if (shift == PMD_SHIFT)
 389                 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa)));
 390 
 391         return pa;
 392 }
 393 
 394 /*
 395  * This function can only be used to modify existing table entries,
 396  * without allocating new levels of table. Note that this permits the
 397  * creation of new section or page entries.
 398  */
 399 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt,
 400                                   phys_addr_t size, pgprot_t prot)
 401 {
 402         if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
 403                 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n",
 404                         &phys, virt);
 405                 return;
 406         }
 407         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
 408                              NO_CONT_MAPPINGS);
 409 }
 410 
 411 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
 412                                unsigned long virt, phys_addr_t size,
 413                                pgprot_t prot, bool page_mappings_only)
 414 {
 415         int flags = 0;
 416 
 417         BUG_ON(mm == &init_mm);
 418 
 419         if (page_mappings_only)
 420                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 421 
 422         __create_pgd_mapping(mm->pgd, phys, virt, size, prot,
 423                              pgd_pgtable_alloc, flags);
 424 }
 425 
 426 static void update_mapping_prot(phys_addr_t phys, unsigned long virt,
 427                                 phys_addr_t size, pgprot_t prot)
 428 {
 429         if ((virt >= PAGE_END) && (virt < VMALLOC_START)) {
 430                 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n",
 431                         &phys, virt);
 432                 return;
 433         }
 434 
 435         __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL,
 436                              NO_CONT_MAPPINGS);
 437 
 438         /* flush the TLBs after updating live kernel mappings */
 439         flush_tlb_kernel_range(virt, virt + size);
 440 }
 441 
 442 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start,
 443                                   phys_addr_t end, pgprot_t prot, int flags)
 444 {
 445         __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start,
 446                              prot, early_pgtable_alloc, flags);
 447 }
 448 
 449 void __init mark_linear_text_alias_ro(void)
 450 {
 451         /*
 452          * Remove the write permissions from the linear alias of .text/.rodata
 453          */
 454         update_mapping_prot(__pa_symbol(_text), (unsigned long)lm_alias(_text),
 455                             (unsigned long)__init_begin - (unsigned long)_text,
 456                             PAGE_KERNEL_RO);
 457 }
 458 
 459 static void __init map_mem(pgd_t *pgdp)
 460 {
 461         phys_addr_t kernel_start = __pa_symbol(_text);
 462         phys_addr_t kernel_end = __pa_symbol(__init_begin);
 463         struct memblock_region *reg;
 464         int flags = 0;
 465 
 466         if (rodata_full || debug_pagealloc_enabled())
 467                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
 468 
 469         /*
 470          * Take care not to create a writable alias for the
 471          * read-only text and rodata sections of the kernel image.
 472          * So temporarily mark them as NOMAP to skip mappings in
 473          * the following for-loop
 474          */
 475         memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
 476 #ifdef CONFIG_KEXEC_CORE
 477         if (crashk_res.end)
 478                 memblock_mark_nomap(crashk_res.start,
 479                                     resource_size(&crashk_res));
 480 #endif
 481 
 482         /* map all the memory banks */
 483         for_each_memblock(memory, reg) {
 484                 phys_addr_t start = reg->base;
 485                 phys_addr_t end = start + reg->size;
 486 
 487                 if (start >= end)
 488                         break;
 489                 if (memblock_is_nomap(reg))
 490                         continue;
 491 
 492                 __map_memblock(pgdp, start, end, PAGE_KERNEL, flags);
 493         }
 494 
 495         /*
 496          * Map the linear alias of the [_text, __init_begin) interval
 497          * as non-executable now, and remove the write permission in
 498          * mark_linear_text_alias_ro() below (which will be called after
 499          * alternative patching has completed). This makes the contents
 500          * of the region accessible to subsystems such as hibernate,
 501          * but protects it from inadvertent modification or execution.
 502          * Note that contiguous mappings cannot be remapped in this way,
 503          * so we should avoid them here.
 504          */
 505         __map_memblock(pgdp, kernel_start, kernel_end,
 506                        PAGE_KERNEL, NO_CONT_MAPPINGS);
 507         memblock_clear_nomap(kernel_start, kernel_end - kernel_start);
 508 
 509 #ifdef CONFIG_KEXEC_CORE
 510         /*
 511          * Use page-level mappings here so that we can shrink the region
 512          * in page granularity and put back unused memory to buddy system
 513          * through /sys/kernel/kexec_crash_size interface.
 514          */
 515         if (crashk_res.end) {
 516                 __map_memblock(pgdp, crashk_res.start, crashk_res.end + 1,
 517                                PAGE_KERNEL,
 518                                NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS);
 519                 memblock_clear_nomap(crashk_res.start,
 520                                      resource_size(&crashk_res));
 521         }
 522 #endif
 523 }
 524 
 525 void mark_rodata_ro(void)
 526 {
 527         unsigned long section_size;
 528 
 529         /*
 530          * mark .rodata as read only. Use __init_begin rather than __end_rodata
 531          * to cover NOTES and EXCEPTION_TABLE.
 532          */
 533         section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata;
 534         update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata,
 535                             section_size, PAGE_KERNEL_RO);
 536 
 537         debug_checkwx();
 538 }
 539 
 540 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end,
 541                                       pgprot_t prot, struct vm_struct *vma,
 542                                       int flags, unsigned long vm_flags)
 543 {
 544         phys_addr_t pa_start = __pa_symbol(va_start);
 545         unsigned long size = va_end - va_start;
 546 
 547         BUG_ON(!PAGE_ALIGNED(pa_start));
 548         BUG_ON(!PAGE_ALIGNED(size));
 549 
 550         __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot,
 551                              early_pgtable_alloc, flags);
 552 
 553         if (!(vm_flags & VM_NO_GUARD))
 554                 size += PAGE_SIZE;
 555 
 556         vma->addr       = va_start;
 557         vma->phys_addr  = pa_start;
 558         vma->size       = size;
 559         vma->flags      = VM_MAP | vm_flags;
 560         vma->caller     = __builtin_return_address(0);
 561 
 562         vm_area_add_early(vma);
 563 }
 564 
 565 static int __init parse_rodata(char *arg)
 566 {
 567         int ret = strtobool(arg, &rodata_enabled);
 568         if (!ret) {
 569                 rodata_full = false;
 570                 return 0;
 571         }
 572 
 573         /* permit 'full' in addition to boolean options */
 574         if (strcmp(arg, "full"))
 575                 return -EINVAL;
 576 
 577         rodata_enabled = true;
 578         rodata_full = true;
 579         return 0;
 580 }
 581 early_param("rodata", parse_rodata);
 582 
 583 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
 584 static int __init map_entry_trampoline(void)
 585 {
 586         pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
 587         phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start);
 588 
 589         /* The trampoline is always mapped and can therefore be global */
 590         pgprot_val(prot) &= ~PTE_NG;
 591 
 592         /* Map only the text into the trampoline page table */
 593         memset(tramp_pg_dir, 0, PGD_SIZE);
 594         __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, PAGE_SIZE,
 595                              prot, __pgd_pgtable_alloc, 0);
 596 
 597         /* Map both the text and data into the kernel page table */
 598         __set_fixmap(FIX_ENTRY_TRAMP_TEXT, pa_start, prot);
 599         if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 600                 extern char __entry_tramp_data_start[];
 601 
 602                 __set_fixmap(FIX_ENTRY_TRAMP_DATA,
 603                              __pa_symbol(__entry_tramp_data_start),
 604                              PAGE_KERNEL_RO);
 605         }
 606 
 607         return 0;
 608 }
 609 core_initcall(map_entry_trampoline);
 610 #endif
 611 
 612 /*
 613  * Create fine-grained mappings for the kernel.
 614  */
 615 static void __init map_kernel(pgd_t *pgdp)
 616 {
 617         static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext,
 618                                 vmlinux_initdata, vmlinux_data;
 619 
 620         /*
 621          * External debuggers may need to write directly to the text
 622          * mapping to install SW breakpoints. Allow this (only) when
 623          * explicitly requested with rodata=off.
 624          */
 625         pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC;
 626 
 627         /*
 628          * Only rodata will be remapped with different permissions later on,
 629          * all other segments are allowed to use contiguous mappings.
 630          */
 631         map_kernel_segment(pgdp, _text, _etext, text_prot, &vmlinux_text, 0,
 632                            VM_NO_GUARD);
 633         map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL,
 634                            &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD);
 635         map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot,
 636                            &vmlinux_inittext, 0, VM_NO_GUARD);
 637         map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL,
 638                            &vmlinux_initdata, 0, VM_NO_GUARD);
 639         map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0);
 640 
 641         if (!READ_ONCE(pgd_val(*pgd_offset_raw(pgdp, FIXADDR_START)))) {
 642                 /*
 643                  * The fixmap falls in a separate pgd to the kernel, and doesn't
 644                  * live in the carveout for the swapper_pg_dir. We can simply
 645                  * re-use the existing dir for the fixmap.
 646                  */
 647                 set_pgd(pgd_offset_raw(pgdp, FIXADDR_START),
 648                         READ_ONCE(*pgd_offset_k(FIXADDR_START)));
 649         } else if (CONFIG_PGTABLE_LEVELS > 3) {
 650                 pgd_t *bm_pgdp;
 651                 pud_t *bm_pudp;
 652                 /*
 653                  * The fixmap shares its top level pgd entry with the kernel
 654                  * mapping. This can really only occur when we are running
 655                  * with 16k/4 levels, so we can simply reuse the pud level
 656                  * entry instead.
 657                  */
 658                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 659                 bm_pgdp = pgd_offset_raw(pgdp, FIXADDR_START);
 660                 bm_pudp = pud_set_fixmap_offset(bm_pgdp, FIXADDR_START);
 661                 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd));
 662                 pud_clear_fixmap();
 663         } else {
 664                 BUG();
 665         }
 666 
 667         kasan_copy_shadow(pgdp);
 668 }
 669 
 670 void __init paging_init(void)
 671 {
 672         pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir));
 673 
 674         map_kernel(pgdp);
 675         map_mem(pgdp);
 676 
 677         pgd_clear_fixmap();
 678 
 679         cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
 680         init_mm.pgd = swapper_pg_dir;
 681 
 682         memblock_free(__pa_symbol(init_pg_dir),
 683                       __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir));
 684 
 685         memblock_allow_resize();
 686 }
 687 
 688 /*
 689  * Check whether a kernel address is valid (derived from arch/x86/).
 690  */
 691 int kern_addr_valid(unsigned long addr)
 692 {
 693         pgd_t *pgdp;
 694         pud_t *pudp, pud;
 695         pmd_t *pmdp, pmd;
 696         pte_t *ptep, pte;
 697 
 698         if ((((long)addr) >> VA_BITS) != -1UL)
 699                 return 0;
 700 
 701         pgdp = pgd_offset_k(addr);
 702         if (pgd_none(READ_ONCE(*pgdp)))
 703                 return 0;
 704 
 705         pudp = pud_offset(pgdp, addr);
 706         pud = READ_ONCE(*pudp);
 707         if (pud_none(pud))
 708                 return 0;
 709 
 710         if (pud_sect(pud))
 711                 return pfn_valid(pud_pfn(pud));
 712 
 713         pmdp = pmd_offset(pudp, addr);
 714         pmd = READ_ONCE(*pmdp);
 715         if (pmd_none(pmd))
 716                 return 0;
 717 
 718         if (pmd_sect(pmd))
 719                 return pfn_valid(pmd_pfn(pmd));
 720 
 721         ptep = pte_offset_kernel(pmdp, addr);
 722         pte = READ_ONCE(*ptep);
 723         if (pte_none(pte))
 724                 return 0;
 725 
 726         return pfn_valid(pte_pfn(pte));
 727 }
 728 #ifdef CONFIG_SPARSEMEM_VMEMMAP
 729 #if !ARM64_SWAPPER_USES_SECTION_MAPS
 730 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 731                 struct vmem_altmap *altmap)
 732 {
 733         return vmemmap_populate_basepages(start, end, node);
 734 }
 735 #else   /* !ARM64_SWAPPER_USES_SECTION_MAPS */
 736 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 737                 struct vmem_altmap *altmap)
 738 {
 739         unsigned long addr = start;
 740         unsigned long next;
 741         pgd_t *pgdp;
 742         pud_t *pudp;
 743         pmd_t *pmdp;
 744 
 745         do {
 746                 next = pmd_addr_end(addr, end);
 747 
 748                 pgdp = vmemmap_pgd_populate(addr, node);
 749                 if (!pgdp)
 750                         return -ENOMEM;
 751 
 752                 pudp = vmemmap_pud_populate(pgdp, addr, node);
 753                 if (!pudp)
 754                         return -ENOMEM;
 755 
 756                 pmdp = pmd_offset(pudp, addr);
 757                 if (pmd_none(READ_ONCE(*pmdp))) {
 758                         void *p = NULL;
 759 
 760                         p = vmemmap_alloc_block_buf(PMD_SIZE, node);
 761                         if (!p)
 762                                 return -ENOMEM;
 763 
 764                         pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL));
 765                 } else
 766                         vmemmap_verify((pte_t *)pmdp, node, addr, next);
 767         } while (addr = next, addr != end);
 768 
 769         return 0;
 770 }
 771 #endif  /* !ARM64_SWAPPER_USES_SECTION_MAPS */
 772 void vmemmap_free(unsigned long start, unsigned long end,
 773                 struct vmem_altmap *altmap)
 774 {
 775 }
 776 #endif  /* CONFIG_SPARSEMEM_VMEMMAP */
 777 
 778 static inline pud_t * fixmap_pud(unsigned long addr)
 779 {
 780         pgd_t *pgdp = pgd_offset_k(addr);
 781         pgd_t pgd = READ_ONCE(*pgdp);
 782 
 783         BUG_ON(pgd_none(pgd) || pgd_bad(pgd));
 784 
 785         return pud_offset_kimg(pgdp, addr);
 786 }
 787 
 788 static inline pmd_t * fixmap_pmd(unsigned long addr)
 789 {
 790         pud_t *pudp = fixmap_pud(addr);
 791         pud_t pud = READ_ONCE(*pudp);
 792 
 793         BUG_ON(pud_none(pud) || pud_bad(pud));
 794 
 795         return pmd_offset_kimg(pudp, addr);
 796 }
 797 
 798 static inline pte_t * fixmap_pte(unsigned long addr)
 799 {
 800         return &bm_pte[pte_index(addr)];
 801 }
 802 
 803 /*
 804  * The p*d_populate functions call virt_to_phys implicitly so they can't be used
 805  * directly on kernel symbols (bm_p*d). This function is called too early to use
 806  * lm_alias so __p*d_populate functions must be used to populate with the
 807  * physical address from __pa_symbol.
 808  */
 809 void __init early_fixmap_init(void)
 810 {
 811         pgd_t *pgdp, pgd;
 812         pud_t *pudp;
 813         pmd_t *pmdp;
 814         unsigned long addr = FIXADDR_START;
 815 
 816         pgdp = pgd_offset_k(addr);
 817         pgd = READ_ONCE(*pgdp);
 818         if (CONFIG_PGTABLE_LEVELS > 3 &&
 819             !(pgd_none(pgd) || pgd_page_paddr(pgd) == __pa_symbol(bm_pud))) {
 820                 /*
 821                  * We only end up here if the kernel mapping and the fixmap
 822                  * share the top level pgd entry, which should only happen on
 823                  * 16k/4 levels configurations.
 824                  */
 825                 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES));
 826                 pudp = pud_offset_kimg(pgdp, addr);
 827         } else {
 828                 if (pgd_none(pgd))
 829                         __pgd_populate(pgdp, __pa_symbol(bm_pud), PUD_TYPE_TABLE);
 830                 pudp = fixmap_pud(addr);
 831         }
 832         if (pud_none(READ_ONCE(*pudp)))
 833                 __pud_populate(pudp, __pa_symbol(bm_pmd), PMD_TYPE_TABLE);
 834         pmdp = fixmap_pmd(addr);
 835         __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE);
 836 
 837         /*
 838          * The boot-ioremap range spans multiple pmds, for which
 839          * we are not prepared:
 840          */
 841         BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
 842                      != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
 843 
 844         if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)))
 845              || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) {
 846                 WARN_ON(1);
 847                 pr_warn("pmdp %p != %p, %p\n",
 848                         pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)),
 849                         fixmap_pmd(fix_to_virt(FIX_BTMAP_END)));
 850                 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
 851                         fix_to_virt(FIX_BTMAP_BEGIN));
 852                 pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
 853                         fix_to_virt(FIX_BTMAP_END));
 854 
 855                 pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
 856                 pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
 857         }
 858 }
 859 
 860 /*
 861  * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we
 862  * ever need to use IPIs for TLB broadcasting, then we're in trouble here.
 863  */
 864 void __set_fixmap(enum fixed_addresses idx,
 865                                phys_addr_t phys, pgprot_t flags)
 866 {
 867         unsigned long addr = __fix_to_virt(idx);
 868         pte_t *ptep;
 869 
 870         BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses);
 871 
 872         ptep = fixmap_pte(addr);
 873 
 874         if (pgprot_val(flags)) {
 875                 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags));
 876         } else {
 877                 pte_clear(&init_mm, addr, ptep);
 878                 flush_tlb_kernel_range(addr, addr+PAGE_SIZE);
 879         }
 880 }
 881 
 882 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot)
 883 {
 884         const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
 885         int offset;
 886         void *dt_virt;
 887 
 888         /*
 889          * Check whether the physical FDT address is set and meets the minimum
 890          * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be
 891          * at least 8 bytes so that we can always access the magic and size
 892          * fields of the FDT header after mapping the first chunk, double check
 893          * here if that is indeed the case.
 894          */
 895         BUILD_BUG_ON(MIN_FDT_ALIGN < 8);
 896         if (!dt_phys || dt_phys % MIN_FDT_ALIGN)
 897                 return NULL;
 898 
 899         /*
 900          * Make sure that the FDT region can be mapped without the need to
 901          * allocate additional translation table pages, so that it is safe
 902          * to call create_mapping_noalloc() this early.
 903          *
 904          * On 64k pages, the FDT will be mapped using PTEs, so we need to
 905          * be in the same PMD as the rest of the fixmap.
 906          * On 4k pages, we'll use section mappings for the FDT so we only
 907          * have to be in the same PUD.
 908          */
 909         BUILD_BUG_ON(dt_virt_base % SZ_2M);
 910 
 911         BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
 912                      __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
 913 
 914         offset = dt_phys % SWAPPER_BLOCK_SIZE;
 915         dt_virt = (void *)dt_virt_base + offset;
 916 
 917         /* map the first chunk so we can read the size from the header */
 918         create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE),
 919                         dt_virt_base, SWAPPER_BLOCK_SIZE, prot);
 920 
 921         if (fdt_magic(dt_virt) != FDT_MAGIC)
 922                 return NULL;
 923 
 924         *size = fdt_totalsize(dt_virt);
 925         if (*size > MAX_FDT_SIZE)
 926                 return NULL;
 927 
 928         if (offset + *size > SWAPPER_BLOCK_SIZE)
 929                 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
 930                                round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot);
 931 
 932         return dt_virt;
 933 }
 934 
 935 int __init arch_ioremap_p4d_supported(void)
 936 {
 937         return 0;
 938 }
 939 
 940 int __init arch_ioremap_pud_supported(void)
 941 {
 942         /*
 943          * Only 4k granule supports level 1 block mappings.
 944          * SW table walks can't handle removal of intermediate entries.
 945          */
 946         return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
 947                !IS_ENABLED(CONFIG_ARM64_PTDUMP_DEBUGFS);
 948 }
 949 
 950 int __init arch_ioremap_pmd_supported(void)
 951 {
 952         /* See arch_ioremap_pud_supported() */
 953         return !IS_ENABLED(CONFIG_ARM64_PTDUMP_DEBUGFS);
 954 }
 955 
 956 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
 957 {
 958         pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot));
 959 
 960         /* Only allow permission changes for now */
 961         if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)),
 962                                    pud_val(new_pud)))
 963                 return 0;
 964 
 965         VM_BUG_ON(phys & ~PUD_MASK);
 966         set_pud(pudp, new_pud);
 967         return 1;
 968 }
 969 
 970 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot)
 971 {
 972         pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot));
 973 
 974         /* Only allow permission changes for now */
 975         if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)),
 976                                    pmd_val(new_pmd)))
 977                 return 0;
 978 
 979         VM_BUG_ON(phys & ~PMD_MASK);
 980         set_pmd(pmdp, new_pmd);
 981         return 1;
 982 }
 983 
 984 int pud_clear_huge(pud_t *pudp)
 985 {
 986         if (!pud_sect(READ_ONCE(*pudp)))
 987                 return 0;
 988         pud_clear(pudp);
 989         return 1;
 990 }
 991 
 992 int pmd_clear_huge(pmd_t *pmdp)
 993 {
 994         if (!pmd_sect(READ_ONCE(*pmdp)))
 995                 return 0;
 996         pmd_clear(pmdp);
 997         return 1;
 998 }
 999 
1000 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr)
1001 {
1002         pte_t *table;
1003         pmd_t pmd;
1004 
1005         pmd = READ_ONCE(*pmdp);
1006 
1007         if (!pmd_table(pmd)) {
1008                 VM_WARN_ON(1);
1009                 return 1;
1010         }
1011 
1012         table = pte_offset_kernel(pmdp, addr);
1013         pmd_clear(pmdp);
1014         __flush_tlb_kernel_pgtable(addr);
1015         pte_free_kernel(NULL, table);
1016         return 1;
1017 }
1018 
1019 int pud_free_pmd_page(pud_t *pudp, unsigned long addr)
1020 {
1021         pmd_t *table;
1022         pmd_t *pmdp;
1023         pud_t pud;
1024         unsigned long next, end;
1025 
1026         pud = READ_ONCE(*pudp);
1027 
1028         if (!pud_table(pud)) {
1029                 VM_WARN_ON(1);
1030                 return 1;
1031         }
1032 
1033         table = pmd_offset(pudp, addr);
1034         pmdp = table;
1035         next = addr;
1036         end = addr + PUD_SIZE;
1037         do {
1038                 pmd_free_pte_page(pmdp, next);
1039         } while (pmdp++, next += PMD_SIZE, next != end);
1040 
1041         pud_clear(pudp);
1042         __flush_tlb_kernel_pgtable(addr);
1043         pmd_free(NULL, table);
1044         return 1;
1045 }
1046 
1047 int p4d_free_pud_page(p4d_t *p4d, unsigned long addr)
1048 {
1049         return 0;       /* Don't attempt a block mapping */
1050 }
1051 
1052 #ifdef CONFIG_MEMORY_HOTPLUG
1053 int arch_add_memory(int nid, u64 start, u64 size,
1054                         struct mhp_restrictions *restrictions)
1055 {
1056         int flags = 0;
1057 
1058         if (rodata_full || debug_pagealloc_enabled())
1059                 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS;
1060 
1061         __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start),
1062                              size, PAGE_KERNEL, __pgd_pgtable_alloc, flags);
1063 
1064         return __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT,
1065                            restrictions);
1066 }
1067 void arch_remove_memory(int nid, u64 start, u64 size,
1068                         struct vmem_altmap *altmap)
1069 {
1070         unsigned long start_pfn = start >> PAGE_SHIFT;
1071         unsigned long nr_pages = size >> PAGE_SHIFT;
1072 
1073         /*
1074          * FIXME: Cleanup page tables (also in arch_add_memory() in case
1075          * adding fails). Until then, this function should only be used
1076          * during memory hotplug (adding memory), not for memory
1077          * unplug. ARCH_ENABLE_MEMORY_HOTREMOVE must not be
1078          * unlocked yet.
1079          */
1080         __remove_pages(start_pfn, nr_pages, altmap);
1081 }
1082 #endif
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root/arch/arm64/mm/mmu.c

DEFINITIONS
