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/memremap.h> 21 #include <linux/memory.h> 22 #include <linux/fs.h> 23 #include <linux/io.h> 24 #include <linux/mm.h> 25 #include <linux/vmalloc.h> 26 #include <linux/set_memory.h> 27 28 #include <asm/barrier.h> 29 #include <asm/cputype.h> 30 #include <asm/fixmap.h> 31 #include <asm/kasan.h> 32 #include <asm/kernel-pgtable.h> 33 #include <asm/sections.h> 34 #include <asm/setup.h> 35 #include <linux/sizes.h> 36 #include <asm/tlb.h> 37 #include <asm/mmu_context.h> 38 #include <asm/ptdump.h> 39 #include <asm/tlbflush.h> 40 #include <asm/pgalloc.h> 41 42 #define NO_BLOCK_MAPPINGS BIT(0) 43 #define NO_CONT_MAPPINGS BIT(1) 44 #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ 45 46 int idmap_t0sz __ro_after_init; 47 48 #if VA_BITS > 48 49 u64 vabits_actual __ro_after_init = VA_BITS_MIN; 50 EXPORT_SYMBOL(vabits_actual); 51 #endif 52 53 u64 kimage_vaddr __ro_after_init = (u64)&_text; 54 EXPORT_SYMBOL(kimage_vaddr); 55 56 u64 kimage_voffset __ro_after_init; 57 EXPORT_SYMBOL(kimage_voffset); 58 59 u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 }; 60 61 /* 62 * The booting CPU updates the failed status @__early_cpu_boot_status, 63 * with MMU turned off. 64 */ 65 long __section(".mmuoff.data.write") __early_cpu_boot_status; 66 67 /* 68 * Empty_zero_page is a special page that is used for zero-initialized data 69 * and COW. 70 */ 71 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 72 EXPORT_SYMBOL(empty_zero_page); 73 74 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; 75 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; 76 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; 77 78 static DEFINE_SPINLOCK(swapper_pgdir_lock); 79 static DEFINE_MUTEX(fixmap_lock); 80 81 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 82 { 83 pgd_t *fixmap_pgdp; 84 85 spin_lock(&swapper_pgdir_lock); 86 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 87 WRITE_ONCE(*fixmap_pgdp, pgd); 88 /* 89 * We need dsb(ishst) here to ensure the page-table-walker sees 90 * our new entry before set_p?d() returns. The fixmap's 91 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 92 */ 93 pgd_clear_fixmap(); 94 spin_unlock(&swapper_pgdir_lock); 95 } 96 97 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 98 unsigned long size, pgprot_t vma_prot) 99 { 100 if (!pfn_is_map_memory(pfn)) 101 return pgprot_noncached(vma_prot); 102 else if (file->f_flags & O_SYNC) 103 return pgprot_writecombine(vma_prot); 104 return vma_prot; 105 } 106 EXPORT_SYMBOL(phys_mem_access_prot); 107 108 static phys_addr_t __init early_pgtable_alloc(int shift) 109 { 110 phys_addr_t phys; 111 void *ptr; 112 113 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 114 MEMBLOCK_ALLOC_NOLEAKTRACE); 115 if (!phys) 116 panic("Failed to allocate page table page\n"); 117 118 /* 119 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE 120 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise 121 * any level of table. 122 */ 123 ptr = pte_set_fixmap(phys); 124 125 memset(ptr, 0, PAGE_SIZE); 126 127 /* 128 * Implicit barriers also ensure the zeroed page is visible to the page 129 * table walker 130 */ 131 pte_clear_fixmap(); 132 133 return phys; 134 } 135 136 static bool pgattr_change_is_safe(u64 old, u64 new) 137 { 138 /* 139 * The following mapping attributes may be updated in live 140 * kernel mappings without the need for break-before-make. 141 */ 142 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 143 144 /* creating or taking down mappings is always safe */ 145 if (old == 0 || new == 0) 146 return true; 147 148 /* live contiguous mappings may not be manipulated at all */ 149 if ((old | new) & PTE_CONT) 150 return false; 151 152 /* Transitioning from Non-Global to Global is unsafe */ 153 if (old & ~new & PTE_NG) 154 return false; 155 156 /* 157 * Changing the memory type between Normal and Normal-Tagged is safe 158 * since Tagged is considered a permission attribute from the 159 * mismatched attribute aliases perspective. 160 */ 161 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 162 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 163 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 164 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 165 mask |= PTE_ATTRINDX_MASK; 166 167 return ((old ^ new) & ~mask) == 0; 168 } 169 170 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 171 phys_addr_t phys, pgprot_t prot) 172 { 173 pte_t *ptep; 174 175 ptep = pte_set_fixmap_offset(pmdp, addr); 176 do { 177 pte_t old_pte = READ_ONCE(*ptep); 178 179 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 180 181 /* 182 * After the PTE entry has been populated once, we 183 * only allow updates to the permission attributes. 184 */ 185 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 186 READ_ONCE(pte_val(*ptep)))); 187 188 phys += PAGE_SIZE; 189 } while (ptep++, addr += PAGE_SIZE, addr != end); 190 191 pte_clear_fixmap(); 192 } 193 194 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 195 unsigned long end, phys_addr_t phys, 196 pgprot_t prot, 197 phys_addr_t (*pgtable_alloc)(int), 198 int flags) 199 { 200 unsigned long next; 201 pmd_t pmd = READ_ONCE(*pmdp); 202 203 BUG_ON(pmd_sect(pmd)); 204 if (pmd_none(pmd)) { 205 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN; 206 phys_addr_t pte_phys; 207 208 if (flags & NO_EXEC_MAPPINGS) 209 pmdval |= PMD_TABLE_PXN; 210 BUG_ON(!pgtable_alloc); 211 pte_phys = pgtable_alloc(PAGE_SHIFT); 212 __pmd_populate(pmdp, pte_phys, pmdval); 213 pmd = READ_ONCE(*pmdp); 214 } 215 BUG_ON(pmd_bad(pmd)); 216 217 do { 218 pgprot_t __prot = prot; 219 220 next = pte_cont_addr_end(addr, end); 221 222 /* use a contiguous mapping if the range is suitably aligned */ 223 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 224 (flags & NO_CONT_MAPPINGS) == 0) 225 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 226 227 init_pte(pmdp, addr, next, phys, __prot); 228 229 phys += next - addr; 230 } while (addr = next, addr != end); 231 } 232 233 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 234 phys_addr_t phys, pgprot_t prot, 235 phys_addr_t (*pgtable_alloc)(int), int flags) 236 { 237 unsigned long next; 238 pmd_t *pmdp; 239 240 pmdp = pmd_set_fixmap_offset(pudp, addr); 241 do { 242 pmd_t old_pmd = READ_ONCE(*pmdp); 243 244 next = pmd_addr_end(addr, end); 245 246 /* try section mapping first */ 247 if (((addr | next | phys) & ~PMD_MASK) == 0 && 248 (flags & NO_BLOCK_MAPPINGS) == 0) { 249 pmd_set_huge(pmdp, phys, prot); 250 251 /* 252 * After the PMD entry has been populated once, we 253 * only allow updates to the permission attributes. 254 */ 255 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 256 READ_ONCE(pmd_val(*pmdp)))); 257 } else { 258 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 259 pgtable_alloc, flags); 260 261 BUG_ON(pmd_val(old_pmd) != 0 && 262 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 263 } 264 phys += next - addr; 265 } while (pmdp++, addr = next, addr != end); 266 267 pmd_clear_fixmap(); 268 } 269 270 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 271 unsigned long end, phys_addr_t phys, 272 pgprot_t prot, 273 phys_addr_t (*pgtable_alloc)(int), int flags) 274 { 275 unsigned long next; 276 pud_t pud = READ_ONCE(*pudp); 277 278 /* 279 * Check for initial section mappings in the pgd/pud. 280 */ 281 BUG_ON(pud_sect(pud)); 282 if (pud_none(pud)) { 283 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN; 284 phys_addr_t pmd_phys; 285 286 if (flags & NO_EXEC_MAPPINGS) 287 pudval |= PUD_TABLE_PXN; 288 BUG_ON(!pgtable_alloc); 289 pmd_phys = pgtable_alloc(PMD_SHIFT); 290 __pud_populate(pudp, pmd_phys, pudval); 291 pud = READ_ONCE(*pudp); 292 } 293 BUG_ON(pud_bad(pud)); 294 295 do { 296 pgprot_t __prot = prot; 297 298 next = pmd_cont_addr_end(addr, end); 299 300 /* use a contiguous mapping if the range is suitably aligned */ 301 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 302 (flags & NO_CONT_MAPPINGS) == 0) 303 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 304 305 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 306 307 phys += next - addr; 308 } while (addr = next, addr != end); 309 } 310 311 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 312 phys_addr_t phys, pgprot_t prot, 313 phys_addr_t (*pgtable_alloc)(int), 314 int flags) 315 { 316 unsigned long next; 317 pud_t *pudp; 318 p4d_t *p4dp = p4d_offset(pgdp, addr); 319 p4d_t p4d = READ_ONCE(*p4dp); 320 321 if (p4d_none(p4d)) { 322 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN; 323 phys_addr_t pud_phys; 324 325 if (flags & NO_EXEC_MAPPINGS) 326 p4dval |= P4D_TABLE_PXN; 327 BUG_ON(!pgtable_alloc); 328 pud_phys = pgtable_alloc(PUD_SHIFT); 329 __p4d_populate(p4dp, pud_phys, p4dval); 330 p4d = READ_ONCE(*p4dp); 331 } 332 BUG_ON(p4d_bad(p4d)); 333 334 pudp = pud_set_fixmap_offset(p4dp, addr); 335 do { 336 pud_t old_pud = READ_ONCE(*pudp); 337 338 next = pud_addr_end(addr, end); 339 340 /* 341 * For 4K granule only, attempt to put down a 1GB block 342 */ 343 if (pud_sect_supported() && 344 ((addr | next | phys) & ~PUD_MASK) == 0 && 345 (flags & NO_BLOCK_MAPPINGS) == 0) { 346 pud_set_huge(pudp, phys, prot); 347 348 /* 349 * After the PUD entry has been populated once, we 350 * only allow updates to the permission attributes. 351 */ 352 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 353 READ_ONCE(pud_val(*pudp)))); 354 } else { 355 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 356 pgtable_alloc, flags); 357 358 BUG_ON(pud_val(old_pud) != 0 && 359 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 360 } 361 phys += next - addr; 362 } while (pudp++, addr = next, addr != end); 363 364 pud_clear_fixmap(); 365 } 366 367 static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, 368 unsigned long virt, phys_addr_t size, 369 pgprot_t prot, 370 phys_addr_t (*pgtable_alloc)(int), 371 int flags) 372 { 373 unsigned long addr, end, next; 374 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 375 376 /* 377 * If the virtual and physical address don't have the same offset 378 * within a page, we cannot map the region as the caller expects. 379 */ 380 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 381 return; 382 383 phys &= PAGE_MASK; 384 addr = virt & PAGE_MASK; 385 end = PAGE_ALIGN(virt + size); 386 387 do { 388 next = pgd_addr_end(addr, end); 389 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 390 flags); 391 phys += next - addr; 392 } while (pgdp++, addr = next, addr != end); 393 } 394 395 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 396 unsigned long virt, phys_addr_t size, 397 pgprot_t prot, 398 phys_addr_t (*pgtable_alloc)(int), 399 int flags) 400 { 401 mutex_lock(&fixmap_lock); 402 __create_pgd_mapping_locked(pgdir, phys, virt, size, prot, 403 pgtable_alloc, flags); 404 mutex_unlock(&fixmap_lock); 405 } 406 407 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 408 extern __alias(__create_pgd_mapping_locked) 409 void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, 410 phys_addr_t size, pgprot_t prot, 411 phys_addr_t (*pgtable_alloc)(int), int flags); 412 #endif 413 414 static phys_addr_t __pgd_pgtable_alloc(int shift) 415 { 416 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 417 BUG_ON(!ptr); 418 419 /* Ensure the zeroed page is visible to the page table walker */ 420 dsb(ishst); 421 return __pa(ptr); 422 } 423 424 static phys_addr_t pgd_pgtable_alloc(int shift) 425 { 426 phys_addr_t pa = __pgd_pgtable_alloc(shift); 427 428 /* 429 * Call proper page table ctor in case later we need to 430 * call core mm functions like apply_to_page_range() on 431 * this pre-allocated page table. 432 * 433 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 434 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 435 */ 436 if (shift == PAGE_SHIFT) 437 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 438 else if (shift == PMD_SHIFT) 439 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 440 441 return pa; 442 } 443 444 /* 445 * This function can only be used to modify existing table entries, 446 * without allocating new levels of table. Note that this permits the 447 * creation of new section or page entries. 448 */ 449 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 450 phys_addr_t size, pgprot_t prot) 451 { 452 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 453 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 454 &phys, virt); 455 return; 456 } 457 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 458 NO_CONT_MAPPINGS); 459 } 460 461 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 462 unsigned long virt, phys_addr_t size, 463 pgprot_t prot, bool page_mappings_only) 464 { 465 int flags = 0; 466 467 BUG_ON(mm == &init_mm); 468 469 if (page_mappings_only) 470 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 471 472 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 473 pgd_pgtable_alloc, flags); 474 } 475 476 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 477 phys_addr_t size, pgprot_t prot) 478 { 479 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 480 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 481 &phys, virt); 482 return; 483 } 484 485 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 486 NO_CONT_MAPPINGS); 487 488 /* flush the TLBs after updating live kernel mappings */ 489 flush_tlb_kernel_range(virt, virt + size); 490 } 491 492 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 493 phys_addr_t end, pgprot_t prot, int flags) 494 { 495 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 496 prot, early_pgtable_alloc, flags); 497 } 498 499 void __init mark_linear_text_alias_ro(void) 500 { 501 /* 502 * Remove the write permissions from the linear alias of .text/.rodata 503 */ 504 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext), 505 (unsigned long)__init_begin - (unsigned long)_stext, 506 PAGE_KERNEL_RO); 507 } 508 509 static bool crash_mem_map __initdata; 510 511 static int __init enable_crash_mem_map(char *arg) 512 { 513 /* 514 * Proper parameter parsing is done by reserve_crashkernel(). We only 515 * need to know if the linear map has to avoid block mappings so that 516 * the crashkernel reservations can be unmapped later. 517 */ 518 crash_mem_map = true; 519 520 return 0; 521 } 522 early_param("crashkernel", enable_crash_mem_map); 523 524 static void __init map_mem(pgd_t *pgdp) 525 { 526 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 527 phys_addr_t kernel_start = __pa_symbol(_stext); 528 phys_addr_t kernel_end = __pa_symbol(__init_begin); 529 phys_addr_t start, end; 530 int flags = NO_EXEC_MAPPINGS; 531 u64 i; 532 533 /* 534 * Setting hierarchical PXNTable attributes on table entries covering 535 * the linear region is only possible if it is guaranteed that no table 536 * entries at any level are being shared between the linear region and 537 * the vmalloc region. Check whether this is true for the PGD level, in 538 * which case it is guaranteed to be true for all other levels as well. 539 */ 540 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); 541 542 if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) 543 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 544 545 /* 546 * Take care not to create a writable alias for the 547 * read-only text and rodata sections of the kernel image. 548 * So temporarily mark them as NOMAP to skip mappings in 549 * the following for-loop 550 */ 551 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 552 553 #ifdef CONFIG_KEXEC_CORE 554 if (crash_mem_map) { 555 if (defer_reserve_crashkernel()) 556 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 557 else if (crashk_res.end) 558 memblock_mark_nomap(crashk_res.start, 559 resource_size(&crashk_res)); 560 } 561 #endif 562 563 /* map all the memory banks */ 564 for_each_mem_range(i, &start, &end) { 565 if (start >= end) 566 break; 567 /* 568 * The linear map must allow allocation tags reading/writing 569 * if MTE is present. Otherwise, it has the same attributes as 570 * PAGE_KERNEL. 571 */ 572 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 573 flags); 574 } 575 576 /* 577 * Map the linear alias of the [_stext, __init_begin) interval 578 * as non-executable now, and remove the write permission in 579 * mark_linear_text_alias_ro() below (which will be called after 580 * alternative patching has completed). This makes the contents 581 * of the region accessible to subsystems such as hibernate, 582 * but protects it from inadvertent modification or execution. 583 * Note that contiguous mappings cannot be remapped in this way, 584 * so we should avoid them here. 585 */ 586 __map_memblock(pgdp, kernel_start, kernel_end, 587 PAGE_KERNEL, NO_CONT_MAPPINGS); 588 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 589 590 /* 591 * Use page-level mappings here so that we can shrink the region 592 * in page granularity and put back unused memory to buddy system 593 * through /sys/kernel/kexec_crash_size interface. 594 */ 595 #ifdef CONFIG_KEXEC_CORE 596 if (crash_mem_map && !defer_reserve_crashkernel()) { 597 if (crashk_res.end) { 598 __map_memblock(pgdp, crashk_res.start, 599 crashk_res.end + 1, 600 PAGE_KERNEL, 601 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 602 memblock_clear_nomap(crashk_res.start, 603 resource_size(&crashk_res)); 604 } 605 } 606 #endif 607 } 608 609 void mark_rodata_ro(void) 610 { 611 unsigned long section_size; 612 613 /* 614 * mark .rodata as read only. Use __init_begin rather than __end_rodata 615 * to cover NOTES and EXCEPTION_TABLE. 616 */ 617 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 618 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 619 section_size, PAGE_KERNEL_RO); 620 621 debug_checkwx(); 622 } 623 624 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 625 pgprot_t prot, struct vm_struct *vma, 626 int flags, unsigned long vm_flags) 627 { 628 phys_addr_t pa_start = __pa_symbol(va_start); 629 unsigned long size = va_end - va_start; 630 631 BUG_ON(!PAGE_ALIGNED(pa_start)); 632 BUG_ON(!PAGE_ALIGNED(size)); 633 634 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 635 early_pgtable_alloc, flags); 636 637 if (!(vm_flags & VM_NO_GUARD)) 638 size += PAGE_SIZE; 639 640 vma->addr = va_start; 641 vma->phys_addr = pa_start; 642 vma->size = size; 643 vma->flags = VM_MAP | vm_flags; 644 vma->caller = __builtin_return_address(0); 645 646 vm_area_add_early(vma); 647 } 648 649 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 650 static int __init map_entry_trampoline(void) 651 { 652 int i; 653 654 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 655 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 656 657 /* The trampoline is always mapped and can therefore be global */ 658 pgprot_val(prot) &= ~PTE_NG; 659 660 /* Map only the text into the trampoline page table */ 661 memset(tramp_pg_dir, 0, PGD_SIZE); 662 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 663 entry_tramp_text_size(), prot, 664 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 665 666 /* Map both the text and data into the kernel page table */ 667 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 668 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 669 pa_start + i * PAGE_SIZE, prot); 670 671 if (IS_ENABLED(CONFIG_RELOCATABLE)) 672 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 673 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 674 675 return 0; 676 } 677 core_initcall(map_entry_trampoline); 678 #endif 679 680 /* 681 * Open coded check for BTI, only for use to determine configuration 682 * for early mappings for before the cpufeature code has run. 683 */ 684 static bool arm64_early_this_cpu_has_bti(void) 685 { 686 u64 pfr1; 687 688 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 689 return false; 690 691 pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1); 692 return cpuid_feature_extract_unsigned_field(pfr1, 693 ID_AA64PFR1_BT_SHIFT); 694 } 695 696 /* 697 * Create fine-grained mappings for the kernel. 698 */ 699 static void __init map_kernel(pgd_t *pgdp) 700 { 701 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 702 vmlinux_initdata, vmlinux_data; 703 704 /* 705 * External debuggers may need to write directly to the text 706 * mapping to install SW breakpoints. Allow this (only) when 707 * explicitly requested with rodata=off. 708 */ 709 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 710 711 /* 712 * If we have a CPU that supports BTI and a kernel built for 713 * BTI then mark the kernel executable text as guarded pages 714 * now so we don't have to rewrite the page tables later. 715 */ 716 if (arm64_early_this_cpu_has_bti()) 717 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 718 719 /* 720 * Only rodata will be remapped with different permissions later on, 721 * all other segments are allowed to use contiguous mappings. 722 */ 723 map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0, 724 VM_NO_GUARD); 725 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 726 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 727 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 728 &vmlinux_inittext, 0, VM_NO_GUARD); 729 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 730 &vmlinux_initdata, 0, VM_NO_GUARD); 731 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 732 733 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { 734 /* 735 * The fixmap falls in a separate pgd to the kernel, and doesn't 736 * live in the carveout for the swapper_pg_dir. We can simply 737 * re-use the existing dir for the fixmap. 738 */ 739 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), 740 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 741 } else if (CONFIG_PGTABLE_LEVELS > 3) { 742 pgd_t *bm_pgdp; 743 p4d_t *bm_p4dp; 744 pud_t *bm_pudp; 745 /* 746 * The fixmap shares its top level pgd entry with the kernel 747 * mapping. This can really only occur when we are running 748 * with 16k/4 levels, so we can simply reuse the pud level 749 * entry instead. 750 */ 751 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 752 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); 753 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); 754 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); 755 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 756 pud_clear_fixmap(); 757 } else { 758 BUG(); 759 } 760 761 kasan_copy_shadow(pgdp); 762 } 763 764 static void __init create_idmap(void) 765 { 766 u64 start = __pa_symbol(__idmap_text_start); 767 u64 size = __pa_symbol(__idmap_text_end) - start; 768 pgd_t *pgd = idmap_pg_dir; 769 u64 pgd_phys; 770 771 /* check if we need an additional level of translation */ 772 if (VA_BITS < 48 && idmap_t0sz < (64 - VA_BITS_MIN)) { 773 pgd_phys = early_pgtable_alloc(PAGE_SHIFT); 774 set_pgd(&idmap_pg_dir[start >> VA_BITS], 775 __pgd(pgd_phys | P4D_TYPE_TABLE)); 776 pgd = __va(pgd_phys); 777 } 778 __create_pgd_mapping(pgd, start, start, size, PAGE_KERNEL_ROX, 779 early_pgtable_alloc, 0); 780 781 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) { 782 extern u32 __idmap_kpti_flag; 783 u64 pa = __pa_symbol(&__idmap_kpti_flag); 784 785 /* 786 * The KPTI G-to-nG conversion code needs a read-write mapping 787 * of its synchronization flag in the ID map. 788 */ 789 __create_pgd_mapping(pgd, pa, pa, sizeof(u32), PAGE_KERNEL, 790 early_pgtable_alloc, 0); 791 } 792 } 793 794 void __init paging_init(void) 795 { 796 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 797 extern pgd_t init_idmap_pg_dir[]; 798 799 idmap_t0sz = 63UL - __fls(__pa_symbol(_end) | GENMASK(VA_BITS_MIN - 1, 0)); 800 801 map_kernel(pgdp); 802 map_mem(pgdp); 803 804 pgd_clear_fixmap(); 805 806 cpu_replace_ttbr1(lm_alias(swapper_pg_dir), init_idmap_pg_dir); 807 init_mm.pgd = swapper_pg_dir; 808 809 memblock_phys_free(__pa_symbol(init_pg_dir), 810 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 811 812 memblock_allow_resize(); 813 814 create_idmap(); 815 } 816 817 /* 818 * Check whether a kernel address is valid (derived from arch/x86/). 819 */ 820 int kern_addr_valid(unsigned long addr) 821 { 822 pgd_t *pgdp; 823 p4d_t *p4dp; 824 pud_t *pudp, pud; 825 pmd_t *pmdp, pmd; 826 pte_t *ptep, pte; 827 828 addr = arch_kasan_reset_tag(addr); 829 if ((((long)addr) >> VA_BITS) != -1UL) 830 return 0; 831 832 pgdp = pgd_offset_k(addr); 833 if (pgd_none(READ_ONCE(*pgdp))) 834 return 0; 835 836 p4dp = p4d_offset(pgdp, addr); 837 if (p4d_none(READ_ONCE(*p4dp))) 838 return 0; 839 840 pudp = pud_offset(p4dp, addr); 841 pud = READ_ONCE(*pudp); 842 if (pud_none(pud)) 843 return 0; 844 845 if (pud_sect(pud)) 846 return pfn_valid(pud_pfn(pud)); 847 848 pmdp = pmd_offset(pudp, addr); 849 pmd = READ_ONCE(*pmdp); 850 if (pmd_none(pmd)) 851 return 0; 852 853 if (pmd_sect(pmd)) 854 return pfn_valid(pmd_pfn(pmd)); 855 856 ptep = pte_offset_kernel(pmdp, addr); 857 pte = READ_ONCE(*ptep); 858 if (pte_none(pte)) 859 return 0; 860 861 return pfn_valid(pte_pfn(pte)); 862 } 863 864 #ifdef CONFIG_MEMORY_HOTPLUG 865 static void free_hotplug_page_range(struct page *page, size_t size, 866 struct vmem_altmap *altmap) 867 { 868 if (altmap) { 869 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 870 } else { 871 WARN_ON(PageReserved(page)); 872 free_pages((unsigned long)page_address(page), get_order(size)); 873 } 874 } 875 876 static void free_hotplug_pgtable_page(struct page *page) 877 { 878 free_hotplug_page_range(page, PAGE_SIZE, NULL); 879 } 880 881 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 882 unsigned long floor, unsigned long ceiling, 883 unsigned long mask) 884 { 885 start &= mask; 886 if (start < floor) 887 return false; 888 889 if (ceiling) { 890 ceiling &= mask; 891 if (!ceiling) 892 return false; 893 } 894 895 if (end - 1 > ceiling - 1) 896 return false; 897 return true; 898 } 899 900 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 901 unsigned long end, bool free_mapped, 902 struct vmem_altmap *altmap) 903 { 904 pte_t *ptep, pte; 905 906 do { 907 ptep = pte_offset_kernel(pmdp, addr); 908 pte = READ_ONCE(*ptep); 909 if (pte_none(pte)) 910 continue; 911 912 WARN_ON(!pte_present(pte)); 913 pte_clear(&init_mm, addr, ptep); 914 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 915 if (free_mapped) 916 free_hotplug_page_range(pte_page(pte), 917 PAGE_SIZE, altmap); 918 } while (addr += PAGE_SIZE, addr < end); 919 } 920 921 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 922 unsigned long end, bool free_mapped, 923 struct vmem_altmap *altmap) 924 { 925 unsigned long next; 926 pmd_t *pmdp, pmd; 927 928 do { 929 next = pmd_addr_end(addr, end); 930 pmdp = pmd_offset(pudp, addr); 931 pmd = READ_ONCE(*pmdp); 932 if (pmd_none(pmd)) 933 continue; 934 935 WARN_ON(!pmd_present(pmd)); 936 if (pmd_sect(pmd)) { 937 pmd_clear(pmdp); 938 939 /* 940 * One TLBI should be sufficient here as the PMD_SIZE 941 * range is mapped with a single block entry. 942 */ 943 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 944 if (free_mapped) 945 free_hotplug_page_range(pmd_page(pmd), 946 PMD_SIZE, altmap); 947 continue; 948 } 949 WARN_ON(!pmd_table(pmd)); 950 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 951 } while (addr = next, addr < end); 952 } 953 954 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 955 unsigned long end, bool free_mapped, 956 struct vmem_altmap *altmap) 957 { 958 unsigned long next; 959 pud_t *pudp, pud; 960 961 do { 962 next = pud_addr_end(addr, end); 963 pudp = pud_offset(p4dp, addr); 964 pud = READ_ONCE(*pudp); 965 if (pud_none(pud)) 966 continue; 967 968 WARN_ON(!pud_present(pud)); 969 if (pud_sect(pud)) { 970 pud_clear(pudp); 971 972 /* 973 * One TLBI should be sufficient here as the PUD_SIZE 974 * range is mapped with a single block entry. 975 */ 976 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 977 if (free_mapped) 978 free_hotplug_page_range(pud_page(pud), 979 PUD_SIZE, altmap); 980 continue; 981 } 982 WARN_ON(!pud_table(pud)); 983 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 984 } while (addr = next, addr < end); 985 } 986 987 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 988 unsigned long end, bool free_mapped, 989 struct vmem_altmap *altmap) 990 { 991 unsigned long next; 992 p4d_t *p4dp, p4d; 993 994 do { 995 next = p4d_addr_end(addr, end); 996 p4dp = p4d_offset(pgdp, addr); 997 p4d = READ_ONCE(*p4dp); 998 if (p4d_none(p4d)) 999 continue; 1000 1001 WARN_ON(!p4d_present(p4d)); 1002 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 1003 } while (addr = next, addr < end); 1004 } 1005 1006 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 1007 bool free_mapped, struct vmem_altmap *altmap) 1008 { 1009 unsigned long next; 1010 pgd_t *pgdp, pgd; 1011 1012 /* 1013 * altmap can only be used as vmemmap mapping backing memory. 1014 * In case the backing memory itself is not being freed, then 1015 * altmap is irrelevant. Warn about this inconsistency when 1016 * encountered. 1017 */ 1018 WARN_ON(!free_mapped && altmap); 1019 1020 do { 1021 next = pgd_addr_end(addr, end); 1022 pgdp = pgd_offset_k(addr); 1023 pgd = READ_ONCE(*pgdp); 1024 if (pgd_none(pgd)) 1025 continue; 1026 1027 WARN_ON(!pgd_present(pgd)); 1028 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 1029 } while (addr = next, addr < end); 1030 } 1031 1032 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 1033 unsigned long end, unsigned long floor, 1034 unsigned long ceiling) 1035 { 1036 pte_t *ptep, pte; 1037 unsigned long i, start = addr; 1038 1039 do { 1040 ptep = pte_offset_kernel(pmdp, addr); 1041 pte = READ_ONCE(*ptep); 1042 1043 /* 1044 * This is just a sanity check here which verifies that 1045 * pte clearing has been done by earlier unmap loops. 1046 */ 1047 WARN_ON(!pte_none(pte)); 1048 } while (addr += PAGE_SIZE, addr < end); 1049 1050 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1051 return; 1052 1053 /* 1054 * Check whether we can free the pte page if the rest of the 1055 * entries are empty. Overlap with other regions have been 1056 * handled by the floor/ceiling check. 1057 */ 1058 ptep = pte_offset_kernel(pmdp, 0UL); 1059 for (i = 0; i < PTRS_PER_PTE; i++) { 1060 if (!pte_none(READ_ONCE(ptep[i]))) 1061 return; 1062 } 1063 1064 pmd_clear(pmdp); 1065 __flush_tlb_kernel_pgtable(start); 1066 free_hotplug_pgtable_page(virt_to_page(ptep)); 1067 } 1068 1069 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1070 unsigned long end, unsigned long floor, 1071 unsigned long ceiling) 1072 { 1073 pmd_t *pmdp, pmd; 1074 unsigned long i, next, start = addr; 1075 1076 do { 1077 next = pmd_addr_end(addr, end); 1078 pmdp = pmd_offset(pudp, addr); 1079 pmd = READ_ONCE(*pmdp); 1080 if (pmd_none(pmd)) 1081 continue; 1082 1083 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1084 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1085 } while (addr = next, addr < end); 1086 1087 if (CONFIG_PGTABLE_LEVELS <= 2) 1088 return; 1089 1090 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1091 return; 1092 1093 /* 1094 * Check whether we can free the pmd page if the rest of the 1095 * entries are empty. Overlap with other regions have been 1096 * handled by the floor/ceiling check. 1097 */ 1098 pmdp = pmd_offset(pudp, 0UL); 1099 for (i = 0; i < PTRS_PER_PMD; i++) { 1100 if (!pmd_none(READ_ONCE(pmdp[i]))) 1101 return; 1102 } 1103 1104 pud_clear(pudp); 1105 __flush_tlb_kernel_pgtable(start); 1106 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1107 } 1108 1109 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1110 unsigned long end, unsigned long floor, 1111 unsigned long ceiling) 1112 { 1113 pud_t *pudp, pud; 1114 unsigned long i, next, start = addr; 1115 1116 do { 1117 next = pud_addr_end(addr, end); 1118 pudp = pud_offset(p4dp, addr); 1119 pud = READ_ONCE(*pudp); 1120 if (pud_none(pud)) 1121 continue; 1122 1123 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1124 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1125 } while (addr = next, addr < end); 1126 1127 if (CONFIG_PGTABLE_LEVELS <= 3) 1128 return; 1129 1130 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1131 return; 1132 1133 /* 1134 * Check whether we can free the pud page if the rest of the 1135 * entries are empty. Overlap with other regions have been 1136 * handled by the floor/ceiling check. 1137 */ 1138 pudp = pud_offset(p4dp, 0UL); 1139 for (i = 0; i < PTRS_PER_PUD; i++) { 1140 if (!pud_none(READ_ONCE(pudp[i]))) 1141 return; 1142 } 1143 1144 p4d_clear(p4dp); 1145 __flush_tlb_kernel_pgtable(start); 1146 free_hotplug_pgtable_page(virt_to_page(pudp)); 1147 } 1148 1149 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1150 unsigned long end, unsigned long floor, 1151 unsigned long ceiling) 1152 { 1153 unsigned long next; 1154 p4d_t *p4dp, p4d; 1155 1156 do { 1157 next = p4d_addr_end(addr, end); 1158 p4dp = p4d_offset(pgdp, addr); 1159 p4d = READ_ONCE(*p4dp); 1160 if (p4d_none(p4d)) 1161 continue; 1162 1163 WARN_ON(!p4d_present(p4d)); 1164 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1165 } while (addr = next, addr < end); 1166 } 1167 1168 static void free_empty_tables(unsigned long addr, unsigned long end, 1169 unsigned long floor, unsigned long ceiling) 1170 { 1171 unsigned long next; 1172 pgd_t *pgdp, pgd; 1173 1174 do { 1175 next = pgd_addr_end(addr, end); 1176 pgdp = pgd_offset_k(addr); 1177 pgd = READ_ONCE(*pgdp); 1178 if (pgd_none(pgd)) 1179 continue; 1180 1181 WARN_ON(!pgd_present(pgd)); 1182 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1183 } while (addr = next, addr < end); 1184 } 1185 #endif 1186 1187 #if !ARM64_KERNEL_USES_PMD_MAPS 1188 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1189 struct vmem_altmap *altmap) 1190 { 1191 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1192 return vmemmap_populate_basepages(start, end, node, altmap); 1193 } 1194 #else /* !ARM64_KERNEL_USES_PMD_MAPS */ 1195 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1196 struct vmem_altmap *altmap) 1197 { 1198 unsigned long addr = start; 1199 unsigned long next; 1200 pgd_t *pgdp; 1201 p4d_t *p4dp; 1202 pud_t *pudp; 1203 pmd_t *pmdp; 1204 1205 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1206 do { 1207 next = pmd_addr_end(addr, end); 1208 1209 pgdp = vmemmap_pgd_populate(addr, node); 1210 if (!pgdp) 1211 return -ENOMEM; 1212 1213 p4dp = vmemmap_p4d_populate(pgdp, addr, node); 1214 if (!p4dp) 1215 return -ENOMEM; 1216 1217 pudp = vmemmap_pud_populate(p4dp, addr, node); 1218 if (!pudp) 1219 return -ENOMEM; 1220 1221 pmdp = pmd_offset(pudp, addr); 1222 if (pmd_none(READ_ONCE(*pmdp))) { 1223 void *p = NULL; 1224 1225 p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); 1226 if (!p) { 1227 if (vmemmap_populate_basepages(addr, next, node, altmap)) 1228 return -ENOMEM; 1229 continue; 1230 } 1231 1232 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1233 } else 1234 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1235 } while (addr = next, addr != end); 1236 1237 return 0; 1238 } 1239 #endif /* !ARM64_KERNEL_USES_PMD_MAPS */ 1240 1241 #ifdef CONFIG_MEMORY_HOTPLUG 1242 void vmemmap_free(unsigned long start, unsigned long end, 1243 struct vmem_altmap *altmap) 1244 { 1245 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1246 1247 unmap_hotplug_range(start, end, true, altmap); 1248 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1249 } 1250 #endif /* CONFIG_MEMORY_HOTPLUG */ 1251 1252 static inline pud_t *fixmap_pud(unsigned long addr) 1253 { 1254 pgd_t *pgdp = pgd_offset_k(addr); 1255 p4d_t *p4dp = p4d_offset(pgdp, addr); 1256 p4d_t p4d = READ_ONCE(*p4dp); 1257 1258 BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); 1259 1260 return pud_offset_kimg(p4dp, addr); 1261 } 1262 1263 static inline pmd_t *fixmap_pmd(unsigned long addr) 1264 { 1265 pud_t *pudp = fixmap_pud(addr); 1266 pud_t pud = READ_ONCE(*pudp); 1267 1268 BUG_ON(pud_none(pud) || pud_bad(pud)); 1269 1270 return pmd_offset_kimg(pudp, addr); 1271 } 1272 1273 static inline pte_t *fixmap_pte(unsigned long addr) 1274 { 1275 return &bm_pte[pte_index(addr)]; 1276 } 1277 1278 /* 1279 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 1280 * directly on kernel symbols (bm_p*d). This function is called too early to use 1281 * lm_alias so __p*d_populate functions must be used to populate with the 1282 * physical address from __pa_symbol. 1283 */ 1284 void __init early_fixmap_init(void) 1285 { 1286 pgd_t *pgdp; 1287 p4d_t *p4dp, p4d; 1288 pud_t *pudp; 1289 pmd_t *pmdp; 1290 unsigned long addr = FIXADDR_START; 1291 1292 pgdp = pgd_offset_k(addr); 1293 p4dp = p4d_offset(pgdp, addr); 1294 p4d = READ_ONCE(*p4dp); 1295 if (CONFIG_PGTABLE_LEVELS > 3 && 1296 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { 1297 /* 1298 * We only end up here if the kernel mapping and the fixmap 1299 * share the top level pgd entry, which should only happen on 1300 * 16k/4 levels configurations. 1301 */ 1302 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 1303 pudp = pud_offset_kimg(p4dp, addr); 1304 } else { 1305 if (p4d_none(p4d)) 1306 __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); 1307 pudp = fixmap_pud(addr); 1308 } 1309 if (pud_none(READ_ONCE(*pudp))) 1310 __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); 1311 pmdp = fixmap_pmd(addr); 1312 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 1313 1314 /* 1315 * The boot-ioremap range spans multiple pmds, for which 1316 * we are not prepared: 1317 */ 1318 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 1319 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 1320 1321 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 1322 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 1323 WARN_ON(1); 1324 pr_warn("pmdp %p != %p, %p\n", 1325 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 1326 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 1327 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 1328 fix_to_virt(FIX_BTMAP_BEGIN)); 1329 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 1330 fix_to_virt(FIX_BTMAP_END)); 1331 1332 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 1333 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 1334 } 1335 } 1336 1337 /* 1338 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 1339 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 1340 */ 1341 void __set_fixmap(enum fixed_addresses idx, 1342 phys_addr_t phys, pgprot_t flags) 1343 { 1344 unsigned long addr = __fix_to_virt(idx); 1345 pte_t *ptep; 1346 1347 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 1348 1349 ptep = fixmap_pte(addr); 1350 1351 if (pgprot_val(flags)) { 1352 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 1353 } else { 1354 pte_clear(&init_mm, addr, ptep); 1355 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 1356 } 1357 } 1358 1359 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 1360 { 1361 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 1362 int offset; 1363 void *dt_virt; 1364 1365 /* 1366 * Check whether the physical FDT address is set and meets the minimum 1367 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 1368 * at least 8 bytes so that we can always access the magic and size 1369 * fields of the FDT header after mapping the first chunk, double check 1370 * here if that is indeed the case. 1371 */ 1372 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 1373 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 1374 return NULL; 1375 1376 /* 1377 * Make sure that the FDT region can be mapped without the need to 1378 * allocate additional translation table pages, so that it is safe 1379 * to call create_mapping_noalloc() this early. 1380 * 1381 * On 64k pages, the FDT will be mapped using PTEs, so we need to 1382 * be in the same PMD as the rest of the fixmap. 1383 * On 4k pages, we'll use section mappings for the FDT so we only 1384 * have to be in the same PUD. 1385 */ 1386 BUILD_BUG_ON(dt_virt_base % SZ_2M); 1387 1388 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 1389 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 1390 1391 offset = dt_phys % SWAPPER_BLOCK_SIZE; 1392 dt_virt = (void *)dt_virt_base + offset; 1393 1394 /* map the first chunk so we can read the size from the header */ 1395 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 1396 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 1397 1398 if (fdt_magic(dt_virt) != FDT_MAGIC) 1399 return NULL; 1400 1401 *size = fdt_totalsize(dt_virt); 1402 if (*size > MAX_FDT_SIZE) 1403 return NULL; 1404 1405 if (offset + *size > SWAPPER_BLOCK_SIZE) 1406 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 1407 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 1408 1409 return dt_virt; 1410 } 1411 1412 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1413 { 1414 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1415 1416 /* Only allow permission changes for now */ 1417 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1418 pud_val(new_pud))) 1419 return 0; 1420 1421 VM_BUG_ON(phys & ~PUD_MASK); 1422 set_pud(pudp, new_pud); 1423 return 1; 1424 } 1425 1426 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1427 { 1428 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1429 1430 /* Only allow permission changes for now */ 1431 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1432 pmd_val(new_pmd))) 1433 return 0; 1434 1435 VM_BUG_ON(phys & ~PMD_MASK); 1436 set_pmd(pmdp, new_pmd); 1437 return 1; 1438 } 1439 1440 int pud_clear_huge(pud_t *pudp) 1441 { 1442 if (!pud_sect(READ_ONCE(*pudp))) 1443 return 0; 1444 pud_clear(pudp); 1445 return 1; 1446 } 1447 1448 int pmd_clear_huge(pmd_t *pmdp) 1449 { 1450 if (!pmd_sect(READ_ONCE(*pmdp))) 1451 return 0; 1452 pmd_clear(pmdp); 1453 return 1; 1454 } 1455 1456 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1457 { 1458 pte_t *table; 1459 pmd_t pmd; 1460 1461 pmd = READ_ONCE(*pmdp); 1462 1463 if (!pmd_table(pmd)) { 1464 VM_WARN_ON(1); 1465 return 1; 1466 } 1467 1468 table = pte_offset_kernel(pmdp, addr); 1469 pmd_clear(pmdp); 1470 __flush_tlb_kernel_pgtable(addr); 1471 pte_free_kernel(NULL, table); 1472 return 1; 1473 } 1474 1475 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1476 { 1477 pmd_t *table; 1478 pmd_t *pmdp; 1479 pud_t pud; 1480 unsigned long next, end; 1481 1482 pud = READ_ONCE(*pudp); 1483 1484 if (!pud_table(pud)) { 1485 VM_WARN_ON(1); 1486 return 1; 1487 } 1488 1489 table = pmd_offset(pudp, addr); 1490 pmdp = table; 1491 next = addr; 1492 end = addr + PUD_SIZE; 1493 do { 1494 pmd_free_pte_page(pmdp, next); 1495 } while (pmdp++, next += PMD_SIZE, next != end); 1496 1497 pud_clear(pudp); 1498 __flush_tlb_kernel_pgtable(addr); 1499 pmd_free(NULL, table); 1500 return 1; 1501 } 1502 1503 #ifdef CONFIG_MEMORY_HOTPLUG 1504 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1505 { 1506 unsigned long end = start + size; 1507 1508 WARN_ON(pgdir != init_mm.pgd); 1509 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1510 1511 unmap_hotplug_range(start, end, false, NULL); 1512 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1513 } 1514 1515 struct range arch_get_mappable_range(void) 1516 { 1517 struct range mhp_range; 1518 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1519 u64 end_linear_pa = __pa(PAGE_END - 1); 1520 1521 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1522 /* 1523 * Check for a wrap, it is possible because of randomized linear 1524 * mapping the start physical address is actually bigger than 1525 * the end physical address. In this case set start to zero 1526 * because [0, end_linear_pa] range must still be able to cover 1527 * all addressable physical addresses. 1528 */ 1529 if (start_linear_pa > end_linear_pa) 1530 start_linear_pa = 0; 1531 } 1532 1533 WARN_ON(start_linear_pa > end_linear_pa); 1534 1535 /* 1536 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1537 * accommodating both its ends but excluding PAGE_END. Max physical 1538 * range which can be mapped inside this linear mapping range, must 1539 * also be derived from its end points. 1540 */ 1541 mhp_range.start = start_linear_pa; 1542 mhp_range.end = end_linear_pa; 1543 1544 return mhp_range; 1545 } 1546 1547 int arch_add_memory(int nid, u64 start, u64 size, 1548 struct mhp_params *params) 1549 { 1550 int ret, flags = NO_EXEC_MAPPINGS; 1551 1552 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1553 1554 /* 1555 * KFENCE requires linear map to be mapped at page granularity, so that 1556 * it is possible to protect/unprotect single pages in the KFENCE pool. 1557 */ 1558 if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) 1559 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1560 1561 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1562 size, params->pgprot, __pgd_pgtable_alloc, 1563 flags); 1564 1565 memblock_clear_nomap(start, size); 1566 1567 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1568 params); 1569 if (ret) 1570 __remove_pgd_mapping(swapper_pg_dir, 1571 __phys_to_virt(start), size); 1572 else { 1573 max_pfn = PFN_UP(start + size); 1574 max_low_pfn = max_pfn; 1575 } 1576 1577 return ret; 1578 } 1579 1580 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1581 { 1582 unsigned long start_pfn = start >> PAGE_SHIFT; 1583 unsigned long nr_pages = size >> PAGE_SHIFT; 1584 1585 __remove_pages(start_pfn, nr_pages, altmap); 1586 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1587 } 1588 1589 /* 1590 * This memory hotplug notifier helps prevent boot memory from being 1591 * inadvertently removed as it blocks pfn range offlining process in 1592 * __offline_pages(). Hence this prevents both offlining as well as 1593 * removal process for boot memory which is initially always online. 1594 * In future if and when boot memory could be removed, this notifier 1595 * should be dropped and free_hotplug_page_range() should handle any 1596 * reserved pages allocated during boot. 1597 */ 1598 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1599 unsigned long action, void *data) 1600 { 1601 struct mem_section *ms; 1602 struct memory_notify *arg = data; 1603 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1604 unsigned long pfn = arg->start_pfn; 1605 1606 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1607 return NOTIFY_OK; 1608 1609 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1610 unsigned long start = PFN_PHYS(pfn); 1611 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1612 1613 ms = __pfn_to_section(pfn); 1614 if (!early_section(ms)) 1615 continue; 1616 1617 if (action == MEM_GOING_OFFLINE) { 1618 /* 1619 * Boot memory removal is not supported. Prevent 1620 * it via blocking any attempted offline request 1621 * for the boot memory and just report it. 1622 */ 1623 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1624 return NOTIFY_BAD; 1625 } else if (action == MEM_OFFLINE) { 1626 /* 1627 * This should have never happened. Boot memory 1628 * offlining should have been prevented by this 1629 * very notifier. Probably some memory removal 1630 * procedure might have changed which would then 1631 * require further debug. 1632 */ 1633 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1634 1635 /* 1636 * Core memory hotplug does not process a return 1637 * code from the notifier for MEM_OFFLINE events. 1638 * The error condition has been reported. Return 1639 * from here as if ignored. 1640 */ 1641 return NOTIFY_DONE; 1642 } 1643 } 1644 return NOTIFY_OK; 1645 } 1646 1647 static struct notifier_block prevent_bootmem_remove_nb = { 1648 .notifier_call = prevent_bootmem_remove_notifier, 1649 }; 1650 1651 /* 1652 * This ensures that boot memory sections on the platform are online 1653 * from early boot. Memory sections could not be prevented from being 1654 * offlined, unless for some reason they are not online to begin with. 1655 * This helps validate the basic assumption on which the above memory 1656 * event notifier works to prevent boot memory section offlining and 1657 * its possible removal. 1658 */ 1659 static void validate_bootmem_online(void) 1660 { 1661 phys_addr_t start, end, addr; 1662 struct mem_section *ms; 1663 u64 i; 1664 1665 /* 1666 * Scanning across all memblock might be expensive 1667 * on some big memory systems. Hence enable this 1668 * validation only with DEBUG_VM. 1669 */ 1670 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1671 return; 1672 1673 for_each_mem_range(i, &start, &end) { 1674 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1675 ms = __pfn_to_section(PHYS_PFN(addr)); 1676 1677 /* 1678 * All memory ranges in the system at this point 1679 * should have been marked as early sections. 1680 */ 1681 WARN_ON(!early_section(ms)); 1682 1683 /* 1684 * Memory notifier mechanism here to prevent boot 1685 * memory offlining depends on the fact that each 1686 * early section memory on the system is initially 1687 * online. Otherwise a given memory section which 1688 * is already offline will be overlooked and can 1689 * be removed completely. Call out such sections. 1690 */ 1691 if (!online_section(ms)) 1692 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1693 addr, addr + (1UL << PA_SECTION_SHIFT)); 1694 } 1695 } 1696 } 1697 1698 static int __init prevent_bootmem_remove_init(void) 1699 { 1700 int ret = 0; 1701 1702 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1703 return ret; 1704 1705 validate_bootmem_online(); 1706 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1707 if (ret) 1708 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1709 1710 return ret; 1711 } 1712 early_initcall(prevent_bootmem_remove_init); 1713 #endif 1714