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 #include <linux/kfence.h> 28 29 #include <asm/barrier.h> 30 #include <asm/cputype.h> 31 #include <asm/fixmap.h> 32 #include <asm/kasan.h> 33 #include <asm/kernel-pgtable.h> 34 #include <asm/sections.h> 35 #include <asm/setup.h> 36 #include <linux/sizes.h> 37 #include <asm/tlb.h> 38 #include <asm/mmu_context.h> 39 #include <asm/ptdump.h> 40 #include <asm/tlbflush.h> 41 #include <asm/pgalloc.h> 42 #include <asm/kfence.h> 43 44 #define NO_BLOCK_MAPPINGS BIT(0) 45 #define NO_CONT_MAPPINGS BIT(1) 46 #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ 47 48 int idmap_t0sz __ro_after_init; 49 50 #if VA_BITS > 48 51 u64 vabits_actual __ro_after_init = VA_BITS_MIN; 52 EXPORT_SYMBOL(vabits_actual); 53 #endif 54 55 u64 kimage_vaddr __ro_after_init = (u64)&_text; 56 EXPORT_SYMBOL(kimage_vaddr); 57 58 u64 kimage_voffset __ro_after_init; 59 EXPORT_SYMBOL(kimage_voffset); 60 61 u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 }; 62 63 /* 64 * The booting CPU updates the failed status @__early_cpu_boot_status, 65 * with MMU turned off. 66 */ 67 long __section(".mmuoff.data.write") __early_cpu_boot_status; 68 69 /* 70 * Empty_zero_page is a special page that is used for zero-initialized data 71 * and COW. 72 */ 73 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 74 EXPORT_SYMBOL(empty_zero_page); 75 76 static DEFINE_SPINLOCK(swapper_pgdir_lock); 77 static DEFINE_MUTEX(fixmap_lock); 78 79 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 80 { 81 pgd_t *fixmap_pgdp; 82 83 spin_lock(&swapper_pgdir_lock); 84 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 85 WRITE_ONCE(*fixmap_pgdp, pgd); 86 /* 87 * We need dsb(ishst) here to ensure the page-table-walker sees 88 * our new entry before set_p?d() returns. The fixmap's 89 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 90 */ 91 pgd_clear_fixmap(); 92 spin_unlock(&swapper_pgdir_lock); 93 } 94 95 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 96 unsigned long size, pgprot_t vma_prot) 97 { 98 if (!pfn_is_map_memory(pfn)) 99 return pgprot_noncached(vma_prot); 100 else if (file->f_flags & O_SYNC) 101 return pgprot_writecombine(vma_prot); 102 return vma_prot; 103 } 104 EXPORT_SYMBOL(phys_mem_access_prot); 105 106 static phys_addr_t __init early_pgtable_alloc(int shift) 107 { 108 phys_addr_t phys; 109 void *ptr; 110 111 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 112 MEMBLOCK_ALLOC_NOLEAKTRACE); 113 if (!phys) 114 panic("Failed to allocate page table page\n"); 115 116 /* 117 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE 118 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise 119 * any level of table. 120 */ 121 ptr = pte_set_fixmap(phys); 122 123 memset(ptr, 0, PAGE_SIZE); 124 125 /* 126 * Implicit barriers also ensure the zeroed page is visible to the page 127 * table walker 128 */ 129 pte_clear_fixmap(); 130 131 return phys; 132 } 133 134 bool pgattr_change_is_safe(u64 old, u64 new) 135 { 136 /* 137 * The following mapping attributes may be updated in live 138 * kernel mappings without the need for break-before-make. 139 */ 140 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 141 142 /* creating or taking down mappings is always safe */ 143 if (!pte_valid(__pte(old)) || !pte_valid(__pte(new))) 144 return true; 145 146 /* A live entry's pfn should not change */ 147 if (pte_pfn(__pte(old)) != pte_pfn(__pte(new))) 148 return false; 149 150 /* live contiguous mappings may not be manipulated at all */ 151 if ((old | new) & PTE_CONT) 152 return false; 153 154 /* Transitioning from Non-Global to Global is unsafe */ 155 if (old & ~new & PTE_NG) 156 return false; 157 158 /* 159 * Changing the memory type between Normal and Normal-Tagged is safe 160 * since Tagged is considered a permission attribute from the 161 * mismatched attribute aliases perspective. 162 */ 163 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 164 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 165 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 166 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 167 mask |= PTE_ATTRINDX_MASK; 168 169 return ((old ^ new) & ~mask) == 0; 170 } 171 172 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 173 phys_addr_t phys, pgprot_t prot) 174 { 175 pte_t *ptep; 176 177 ptep = pte_set_fixmap_offset(pmdp, addr); 178 do { 179 pte_t old_pte = READ_ONCE(*ptep); 180 181 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 182 183 /* 184 * After the PTE entry has been populated once, we 185 * only allow updates to the permission attributes. 186 */ 187 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 188 READ_ONCE(pte_val(*ptep)))); 189 190 phys += PAGE_SIZE; 191 } while (ptep++, addr += PAGE_SIZE, addr != end); 192 193 pte_clear_fixmap(); 194 } 195 196 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 197 unsigned long end, phys_addr_t phys, 198 pgprot_t prot, 199 phys_addr_t (*pgtable_alloc)(int), 200 int flags) 201 { 202 unsigned long next; 203 pmd_t pmd = READ_ONCE(*pmdp); 204 205 BUG_ON(pmd_sect(pmd)); 206 if (pmd_none(pmd)) { 207 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN; 208 phys_addr_t pte_phys; 209 210 if (flags & NO_EXEC_MAPPINGS) 211 pmdval |= PMD_TABLE_PXN; 212 BUG_ON(!pgtable_alloc); 213 pte_phys = pgtable_alloc(PAGE_SHIFT); 214 __pmd_populate(pmdp, pte_phys, pmdval); 215 pmd = READ_ONCE(*pmdp); 216 } 217 BUG_ON(pmd_bad(pmd)); 218 219 do { 220 pgprot_t __prot = prot; 221 222 next = pte_cont_addr_end(addr, end); 223 224 /* use a contiguous mapping if the range is suitably aligned */ 225 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 226 (flags & NO_CONT_MAPPINGS) == 0) 227 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 228 229 init_pte(pmdp, addr, next, phys, __prot); 230 231 phys += next - addr; 232 } while (addr = next, addr != end); 233 } 234 235 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 236 phys_addr_t phys, pgprot_t prot, 237 phys_addr_t (*pgtable_alloc)(int), int flags) 238 { 239 unsigned long next; 240 pmd_t *pmdp; 241 242 pmdp = pmd_set_fixmap_offset(pudp, addr); 243 do { 244 pmd_t old_pmd = READ_ONCE(*pmdp); 245 246 next = pmd_addr_end(addr, end); 247 248 /* try section mapping first */ 249 if (((addr | next | phys) & ~PMD_MASK) == 0 && 250 (flags & NO_BLOCK_MAPPINGS) == 0) { 251 pmd_set_huge(pmdp, phys, prot); 252 253 /* 254 * After the PMD entry has been populated once, we 255 * only allow updates to the permission attributes. 256 */ 257 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 258 READ_ONCE(pmd_val(*pmdp)))); 259 } else { 260 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 261 pgtable_alloc, flags); 262 263 BUG_ON(pmd_val(old_pmd) != 0 && 264 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 265 } 266 phys += next - addr; 267 } while (pmdp++, addr = next, addr != end); 268 269 pmd_clear_fixmap(); 270 } 271 272 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 273 unsigned long end, phys_addr_t phys, 274 pgprot_t prot, 275 phys_addr_t (*pgtable_alloc)(int), int flags) 276 { 277 unsigned long next; 278 pud_t pud = READ_ONCE(*pudp); 279 280 /* 281 * Check for initial section mappings in the pgd/pud. 282 */ 283 BUG_ON(pud_sect(pud)); 284 if (pud_none(pud)) { 285 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN; 286 phys_addr_t pmd_phys; 287 288 if (flags & NO_EXEC_MAPPINGS) 289 pudval |= PUD_TABLE_PXN; 290 BUG_ON(!pgtable_alloc); 291 pmd_phys = pgtable_alloc(PMD_SHIFT); 292 __pud_populate(pudp, pmd_phys, pudval); 293 pud = READ_ONCE(*pudp); 294 } 295 BUG_ON(pud_bad(pud)); 296 297 do { 298 pgprot_t __prot = prot; 299 300 next = pmd_cont_addr_end(addr, end); 301 302 /* use a contiguous mapping if the range is suitably aligned */ 303 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 304 (flags & NO_CONT_MAPPINGS) == 0) 305 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 306 307 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 308 309 phys += next - addr; 310 } while (addr = next, addr != end); 311 } 312 313 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 314 phys_addr_t phys, pgprot_t prot, 315 phys_addr_t (*pgtable_alloc)(int), 316 int flags) 317 { 318 unsigned long next; 319 pud_t *pudp; 320 p4d_t *p4dp = p4d_offset(pgdp, addr); 321 p4d_t p4d = READ_ONCE(*p4dp); 322 323 if (p4d_none(p4d)) { 324 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN; 325 phys_addr_t pud_phys; 326 327 if (flags & NO_EXEC_MAPPINGS) 328 p4dval |= P4D_TABLE_PXN; 329 BUG_ON(!pgtable_alloc); 330 pud_phys = pgtable_alloc(PUD_SHIFT); 331 __p4d_populate(p4dp, pud_phys, p4dval); 332 p4d = READ_ONCE(*p4dp); 333 } 334 BUG_ON(p4d_bad(p4d)); 335 336 pudp = pud_set_fixmap_offset(p4dp, addr); 337 do { 338 pud_t old_pud = READ_ONCE(*pudp); 339 340 next = pud_addr_end(addr, end); 341 342 /* 343 * For 4K granule only, attempt to put down a 1GB block 344 */ 345 if (pud_sect_supported() && 346 ((addr | next | phys) & ~PUD_MASK) == 0 && 347 (flags & NO_BLOCK_MAPPINGS) == 0) { 348 pud_set_huge(pudp, phys, prot); 349 350 /* 351 * After the PUD entry has been populated once, we 352 * only allow updates to the permission attributes. 353 */ 354 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 355 READ_ONCE(pud_val(*pudp)))); 356 } else { 357 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 358 pgtable_alloc, flags); 359 360 BUG_ON(pud_val(old_pud) != 0 && 361 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 362 } 363 phys += next - addr; 364 } while (pudp++, addr = next, addr != end); 365 366 pud_clear_fixmap(); 367 } 368 369 static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, 370 unsigned long virt, phys_addr_t size, 371 pgprot_t prot, 372 phys_addr_t (*pgtable_alloc)(int), 373 int flags) 374 { 375 unsigned long addr, end, next; 376 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 377 378 /* 379 * If the virtual and physical address don't have the same offset 380 * within a page, we cannot map the region as the caller expects. 381 */ 382 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 383 return; 384 385 phys &= PAGE_MASK; 386 addr = virt & PAGE_MASK; 387 end = PAGE_ALIGN(virt + size); 388 389 do { 390 next = pgd_addr_end(addr, end); 391 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 392 flags); 393 phys += next - addr; 394 } while (pgdp++, addr = next, addr != end); 395 } 396 397 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 398 unsigned long virt, phys_addr_t size, 399 pgprot_t prot, 400 phys_addr_t (*pgtable_alloc)(int), 401 int flags) 402 { 403 mutex_lock(&fixmap_lock); 404 __create_pgd_mapping_locked(pgdir, phys, virt, size, prot, 405 pgtable_alloc, flags); 406 mutex_unlock(&fixmap_lock); 407 } 408 409 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 410 extern __alias(__create_pgd_mapping_locked) 411 void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, 412 phys_addr_t size, pgprot_t prot, 413 phys_addr_t (*pgtable_alloc)(int), int flags); 414 #endif 415 416 static phys_addr_t __pgd_pgtable_alloc(int shift) 417 { 418 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 419 BUG_ON(!ptr); 420 421 /* Ensure the zeroed page is visible to the page table walker */ 422 dsb(ishst); 423 return __pa(ptr); 424 } 425 426 static phys_addr_t pgd_pgtable_alloc(int shift) 427 { 428 phys_addr_t pa = __pgd_pgtable_alloc(shift); 429 430 /* 431 * Call proper page table ctor in case later we need to 432 * call core mm functions like apply_to_page_range() on 433 * this pre-allocated page table. 434 * 435 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 436 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 437 */ 438 if (shift == PAGE_SHIFT) 439 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 440 else if (shift == PMD_SHIFT) 441 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 442 443 return pa; 444 } 445 446 /* 447 * This function can only be used to modify existing table entries, 448 * without allocating new levels of table. Note that this permits the 449 * creation of new section or page entries. 450 */ 451 void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 452 phys_addr_t size, pgprot_t prot) 453 { 454 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 455 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 456 &phys, virt); 457 return; 458 } 459 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 460 NO_CONT_MAPPINGS); 461 } 462 463 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 464 unsigned long virt, phys_addr_t size, 465 pgprot_t prot, bool page_mappings_only) 466 { 467 int flags = 0; 468 469 BUG_ON(mm == &init_mm); 470 471 if (page_mappings_only) 472 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 473 474 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 475 pgd_pgtable_alloc, flags); 476 } 477 478 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 479 phys_addr_t size, pgprot_t prot) 480 { 481 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 482 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 483 &phys, virt); 484 return; 485 } 486 487 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 488 NO_CONT_MAPPINGS); 489 490 /* flush the TLBs after updating live kernel mappings */ 491 flush_tlb_kernel_range(virt, virt + size); 492 } 493 494 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 495 phys_addr_t end, pgprot_t prot, int flags) 496 { 497 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 498 prot, early_pgtable_alloc, flags); 499 } 500 501 void __init mark_linear_text_alias_ro(void) 502 { 503 /* 504 * Remove the write permissions from the linear alias of .text/.rodata 505 */ 506 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext), 507 (unsigned long)__init_begin - (unsigned long)_stext, 508 PAGE_KERNEL_RO); 509 } 510 511 #ifdef CONFIG_KFENCE 512 513 bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL; 514 515 /* early_param() will be parsed before map_mem() below. */ 516 static int __init parse_kfence_early_init(char *arg) 517 { 518 int val; 519 520 if (get_option(&arg, &val)) 521 kfence_early_init = !!val; 522 return 0; 523 } 524 early_param("kfence.sample_interval", parse_kfence_early_init); 525 526 static phys_addr_t __init arm64_kfence_alloc_pool(void) 527 { 528 phys_addr_t kfence_pool; 529 530 if (!kfence_early_init) 531 return 0; 532 533 kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); 534 if (!kfence_pool) { 535 pr_err("failed to allocate kfence pool\n"); 536 kfence_early_init = false; 537 return 0; 538 } 539 540 /* Temporarily mark as NOMAP. */ 541 memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); 542 543 return kfence_pool; 544 } 545 546 static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) 547 { 548 if (!kfence_pool) 549 return; 550 551 /* KFENCE pool needs page-level mapping. */ 552 __map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE, 553 pgprot_tagged(PAGE_KERNEL), 554 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 555 memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); 556 __kfence_pool = phys_to_virt(kfence_pool); 557 } 558 #else /* CONFIG_KFENCE */ 559 560 static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; } 561 static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { } 562 563 #endif /* CONFIG_KFENCE */ 564 565 static void __init map_mem(pgd_t *pgdp) 566 { 567 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 568 phys_addr_t kernel_start = __pa_symbol(_stext); 569 phys_addr_t kernel_end = __pa_symbol(__init_begin); 570 phys_addr_t start, end; 571 phys_addr_t early_kfence_pool; 572 int flags = NO_EXEC_MAPPINGS; 573 u64 i; 574 575 /* 576 * Setting hierarchical PXNTable attributes on table entries covering 577 * the linear region is only possible if it is guaranteed that no table 578 * entries at any level are being shared between the linear region and 579 * the vmalloc region. Check whether this is true for the PGD level, in 580 * which case it is guaranteed to be true for all other levels as well. 581 */ 582 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); 583 584 early_kfence_pool = arm64_kfence_alloc_pool(); 585 586 if (can_set_direct_map()) 587 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 588 589 /* 590 * Take care not to create a writable alias for the 591 * read-only text and rodata sections of the kernel image. 592 * So temporarily mark them as NOMAP to skip mappings in 593 * the following for-loop 594 */ 595 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 596 597 /* map all the memory banks */ 598 for_each_mem_range(i, &start, &end) { 599 if (start >= end) 600 break; 601 /* 602 * The linear map must allow allocation tags reading/writing 603 * if MTE is present. Otherwise, it has the same attributes as 604 * PAGE_KERNEL. 605 */ 606 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 607 flags); 608 } 609 610 /* 611 * Map the linear alias of the [_stext, __init_begin) interval 612 * as non-executable now, and remove the write permission in 613 * mark_linear_text_alias_ro() below (which will be called after 614 * alternative patching has completed). This makes the contents 615 * of the region accessible to subsystems such as hibernate, 616 * but protects it from inadvertent modification or execution. 617 * Note that contiguous mappings cannot be remapped in this way, 618 * so we should avoid them here. 619 */ 620 __map_memblock(pgdp, kernel_start, kernel_end, 621 PAGE_KERNEL, NO_CONT_MAPPINGS); 622 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 623 arm64_kfence_map_pool(early_kfence_pool, pgdp); 624 } 625 626 void mark_rodata_ro(void) 627 { 628 unsigned long section_size; 629 630 /* 631 * mark .rodata as read only. Use __init_begin rather than __end_rodata 632 * to cover NOTES and EXCEPTION_TABLE. 633 */ 634 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 635 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 636 section_size, PAGE_KERNEL_RO); 637 638 debug_checkwx(); 639 } 640 641 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 642 pgprot_t prot, struct vm_struct *vma, 643 int flags, unsigned long vm_flags) 644 { 645 phys_addr_t pa_start = __pa_symbol(va_start); 646 unsigned long size = va_end - va_start; 647 648 BUG_ON(!PAGE_ALIGNED(pa_start)); 649 BUG_ON(!PAGE_ALIGNED(size)); 650 651 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 652 early_pgtable_alloc, flags); 653 654 if (!(vm_flags & VM_NO_GUARD)) 655 size += PAGE_SIZE; 656 657 vma->addr = va_start; 658 vma->phys_addr = pa_start; 659 vma->size = size; 660 vma->flags = VM_MAP | vm_flags; 661 vma->caller = __builtin_return_address(0); 662 663 vm_area_add_early(vma); 664 } 665 666 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 667 static int __init map_entry_trampoline(void) 668 { 669 int i; 670 671 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 672 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 673 674 /* The trampoline is always mapped and can therefore be global */ 675 pgprot_val(prot) &= ~PTE_NG; 676 677 /* Map only the text into the trampoline page table */ 678 memset(tramp_pg_dir, 0, PGD_SIZE); 679 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 680 entry_tramp_text_size(), prot, 681 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 682 683 /* Map both the text and data into the kernel page table */ 684 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 685 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 686 pa_start + i * PAGE_SIZE, prot); 687 688 if (IS_ENABLED(CONFIG_RELOCATABLE)) 689 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 690 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 691 692 return 0; 693 } 694 core_initcall(map_entry_trampoline); 695 #endif 696 697 /* 698 * Open coded check for BTI, only for use to determine configuration 699 * for early mappings for before the cpufeature code has run. 700 */ 701 static bool arm64_early_this_cpu_has_bti(void) 702 { 703 u64 pfr1; 704 705 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 706 return false; 707 708 pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1); 709 return cpuid_feature_extract_unsigned_field(pfr1, 710 ID_AA64PFR1_EL1_BT_SHIFT); 711 } 712 713 /* 714 * Create fine-grained mappings for the kernel. 715 */ 716 static void __init map_kernel(pgd_t *pgdp) 717 { 718 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 719 vmlinux_initdata, vmlinux_data; 720 721 /* 722 * External debuggers may need to write directly to the text 723 * mapping to install SW breakpoints. Allow this (only) when 724 * explicitly requested with rodata=off. 725 */ 726 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 727 728 /* 729 * If we have a CPU that supports BTI and a kernel built for 730 * BTI then mark the kernel executable text as guarded pages 731 * now so we don't have to rewrite the page tables later. 732 */ 733 if (arm64_early_this_cpu_has_bti()) 734 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 735 736 /* 737 * Only rodata will be remapped with different permissions later on, 738 * all other segments are allowed to use contiguous mappings. 739 */ 740 map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0, 741 VM_NO_GUARD); 742 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 743 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 744 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 745 &vmlinux_inittext, 0, VM_NO_GUARD); 746 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 747 &vmlinux_initdata, 0, VM_NO_GUARD); 748 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 749 750 fixmap_copy(pgdp); 751 kasan_copy_shadow(pgdp); 752 } 753 754 static void __init create_idmap(void) 755 { 756 u64 start = __pa_symbol(__idmap_text_start); 757 u64 size = __pa_symbol(__idmap_text_end) - start; 758 pgd_t *pgd = idmap_pg_dir; 759 u64 pgd_phys; 760 761 /* check if we need an additional level of translation */ 762 if (VA_BITS < 48 && idmap_t0sz < (64 - VA_BITS_MIN)) { 763 pgd_phys = early_pgtable_alloc(PAGE_SHIFT); 764 set_pgd(&idmap_pg_dir[start >> VA_BITS], 765 __pgd(pgd_phys | P4D_TYPE_TABLE)); 766 pgd = __va(pgd_phys); 767 } 768 __create_pgd_mapping(pgd, start, start, size, PAGE_KERNEL_ROX, 769 early_pgtable_alloc, 0); 770 771 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) { 772 extern u32 __idmap_kpti_flag; 773 u64 pa = __pa_symbol(&__idmap_kpti_flag); 774 775 /* 776 * The KPTI G-to-nG conversion code needs a read-write mapping 777 * of its synchronization flag in the ID map. 778 */ 779 __create_pgd_mapping(pgd, pa, pa, sizeof(u32), PAGE_KERNEL, 780 early_pgtable_alloc, 0); 781 } 782 } 783 784 void __init paging_init(void) 785 { 786 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 787 extern pgd_t init_idmap_pg_dir[]; 788 789 idmap_t0sz = 63UL - __fls(__pa_symbol(_end) | GENMASK(VA_BITS_MIN - 1, 0)); 790 791 map_kernel(pgdp); 792 map_mem(pgdp); 793 794 pgd_clear_fixmap(); 795 796 cpu_replace_ttbr1(lm_alias(swapper_pg_dir), init_idmap_pg_dir); 797 init_mm.pgd = swapper_pg_dir; 798 799 memblock_phys_free(__pa_symbol(init_pg_dir), 800 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 801 802 memblock_allow_resize(); 803 804 create_idmap(); 805 } 806 807 #ifdef CONFIG_MEMORY_HOTPLUG 808 static void free_hotplug_page_range(struct page *page, size_t size, 809 struct vmem_altmap *altmap) 810 { 811 if (altmap) { 812 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 813 } else { 814 WARN_ON(PageReserved(page)); 815 free_pages((unsigned long)page_address(page), get_order(size)); 816 } 817 } 818 819 static void free_hotplug_pgtable_page(struct page *page) 820 { 821 free_hotplug_page_range(page, PAGE_SIZE, NULL); 822 } 823 824 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 825 unsigned long floor, unsigned long ceiling, 826 unsigned long mask) 827 { 828 start &= mask; 829 if (start < floor) 830 return false; 831 832 if (ceiling) { 833 ceiling &= mask; 834 if (!ceiling) 835 return false; 836 } 837 838 if (end - 1 > ceiling - 1) 839 return false; 840 return true; 841 } 842 843 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 844 unsigned long end, bool free_mapped, 845 struct vmem_altmap *altmap) 846 { 847 pte_t *ptep, pte; 848 849 do { 850 ptep = pte_offset_kernel(pmdp, addr); 851 pte = READ_ONCE(*ptep); 852 if (pte_none(pte)) 853 continue; 854 855 WARN_ON(!pte_present(pte)); 856 pte_clear(&init_mm, addr, ptep); 857 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 858 if (free_mapped) 859 free_hotplug_page_range(pte_page(pte), 860 PAGE_SIZE, altmap); 861 } while (addr += PAGE_SIZE, addr < end); 862 } 863 864 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 865 unsigned long end, bool free_mapped, 866 struct vmem_altmap *altmap) 867 { 868 unsigned long next; 869 pmd_t *pmdp, pmd; 870 871 do { 872 next = pmd_addr_end(addr, end); 873 pmdp = pmd_offset(pudp, addr); 874 pmd = READ_ONCE(*pmdp); 875 if (pmd_none(pmd)) 876 continue; 877 878 WARN_ON(!pmd_present(pmd)); 879 if (pmd_sect(pmd)) { 880 pmd_clear(pmdp); 881 882 /* 883 * One TLBI should be sufficient here as the PMD_SIZE 884 * range is mapped with a single block entry. 885 */ 886 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 887 if (free_mapped) 888 free_hotplug_page_range(pmd_page(pmd), 889 PMD_SIZE, altmap); 890 continue; 891 } 892 WARN_ON(!pmd_table(pmd)); 893 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 894 } while (addr = next, addr < end); 895 } 896 897 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 898 unsigned long end, bool free_mapped, 899 struct vmem_altmap *altmap) 900 { 901 unsigned long next; 902 pud_t *pudp, pud; 903 904 do { 905 next = pud_addr_end(addr, end); 906 pudp = pud_offset(p4dp, addr); 907 pud = READ_ONCE(*pudp); 908 if (pud_none(pud)) 909 continue; 910 911 WARN_ON(!pud_present(pud)); 912 if (pud_sect(pud)) { 913 pud_clear(pudp); 914 915 /* 916 * One TLBI should be sufficient here as the PUD_SIZE 917 * range is mapped with a single block entry. 918 */ 919 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 920 if (free_mapped) 921 free_hotplug_page_range(pud_page(pud), 922 PUD_SIZE, altmap); 923 continue; 924 } 925 WARN_ON(!pud_table(pud)); 926 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 927 } while (addr = next, addr < end); 928 } 929 930 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 931 unsigned long end, bool free_mapped, 932 struct vmem_altmap *altmap) 933 { 934 unsigned long next; 935 p4d_t *p4dp, p4d; 936 937 do { 938 next = p4d_addr_end(addr, end); 939 p4dp = p4d_offset(pgdp, addr); 940 p4d = READ_ONCE(*p4dp); 941 if (p4d_none(p4d)) 942 continue; 943 944 WARN_ON(!p4d_present(p4d)); 945 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 946 } while (addr = next, addr < end); 947 } 948 949 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 950 bool free_mapped, struct vmem_altmap *altmap) 951 { 952 unsigned long next; 953 pgd_t *pgdp, pgd; 954 955 /* 956 * altmap can only be used as vmemmap mapping backing memory. 957 * In case the backing memory itself is not being freed, then 958 * altmap is irrelevant. Warn about this inconsistency when 959 * encountered. 960 */ 961 WARN_ON(!free_mapped && altmap); 962 963 do { 964 next = pgd_addr_end(addr, end); 965 pgdp = pgd_offset_k(addr); 966 pgd = READ_ONCE(*pgdp); 967 if (pgd_none(pgd)) 968 continue; 969 970 WARN_ON(!pgd_present(pgd)); 971 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 972 } while (addr = next, addr < end); 973 } 974 975 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 976 unsigned long end, unsigned long floor, 977 unsigned long ceiling) 978 { 979 pte_t *ptep, pte; 980 unsigned long i, start = addr; 981 982 do { 983 ptep = pte_offset_kernel(pmdp, addr); 984 pte = READ_ONCE(*ptep); 985 986 /* 987 * This is just a sanity check here which verifies that 988 * pte clearing has been done by earlier unmap loops. 989 */ 990 WARN_ON(!pte_none(pte)); 991 } while (addr += PAGE_SIZE, addr < end); 992 993 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 994 return; 995 996 /* 997 * Check whether we can free the pte page if the rest of the 998 * entries are empty. Overlap with other regions have been 999 * handled by the floor/ceiling check. 1000 */ 1001 ptep = pte_offset_kernel(pmdp, 0UL); 1002 for (i = 0; i < PTRS_PER_PTE; i++) { 1003 if (!pte_none(READ_ONCE(ptep[i]))) 1004 return; 1005 } 1006 1007 pmd_clear(pmdp); 1008 __flush_tlb_kernel_pgtable(start); 1009 free_hotplug_pgtable_page(virt_to_page(ptep)); 1010 } 1011 1012 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1013 unsigned long end, unsigned long floor, 1014 unsigned long ceiling) 1015 { 1016 pmd_t *pmdp, pmd; 1017 unsigned long i, next, start = addr; 1018 1019 do { 1020 next = pmd_addr_end(addr, end); 1021 pmdp = pmd_offset(pudp, addr); 1022 pmd = READ_ONCE(*pmdp); 1023 if (pmd_none(pmd)) 1024 continue; 1025 1026 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1027 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1028 } while (addr = next, addr < end); 1029 1030 if (CONFIG_PGTABLE_LEVELS <= 2) 1031 return; 1032 1033 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1034 return; 1035 1036 /* 1037 * Check whether we can free the pmd page if the rest of the 1038 * entries are empty. Overlap with other regions have been 1039 * handled by the floor/ceiling check. 1040 */ 1041 pmdp = pmd_offset(pudp, 0UL); 1042 for (i = 0; i < PTRS_PER_PMD; i++) { 1043 if (!pmd_none(READ_ONCE(pmdp[i]))) 1044 return; 1045 } 1046 1047 pud_clear(pudp); 1048 __flush_tlb_kernel_pgtable(start); 1049 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1050 } 1051 1052 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1053 unsigned long end, unsigned long floor, 1054 unsigned long ceiling) 1055 { 1056 pud_t *pudp, pud; 1057 unsigned long i, next, start = addr; 1058 1059 do { 1060 next = pud_addr_end(addr, end); 1061 pudp = pud_offset(p4dp, addr); 1062 pud = READ_ONCE(*pudp); 1063 if (pud_none(pud)) 1064 continue; 1065 1066 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1067 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1068 } while (addr = next, addr < end); 1069 1070 if (CONFIG_PGTABLE_LEVELS <= 3) 1071 return; 1072 1073 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1074 return; 1075 1076 /* 1077 * Check whether we can free the pud page if the rest of the 1078 * entries are empty. Overlap with other regions have been 1079 * handled by the floor/ceiling check. 1080 */ 1081 pudp = pud_offset(p4dp, 0UL); 1082 for (i = 0; i < PTRS_PER_PUD; i++) { 1083 if (!pud_none(READ_ONCE(pudp[i]))) 1084 return; 1085 } 1086 1087 p4d_clear(p4dp); 1088 __flush_tlb_kernel_pgtable(start); 1089 free_hotplug_pgtable_page(virt_to_page(pudp)); 1090 } 1091 1092 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1093 unsigned long end, unsigned long floor, 1094 unsigned long ceiling) 1095 { 1096 unsigned long next; 1097 p4d_t *p4dp, p4d; 1098 1099 do { 1100 next = p4d_addr_end(addr, end); 1101 p4dp = p4d_offset(pgdp, addr); 1102 p4d = READ_ONCE(*p4dp); 1103 if (p4d_none(p4d)) 1104 continue; 1105 1106 WARN_ON(!p4d_present(p4d)); 1107 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1108 } while (addr = next, addr < end); 1109 } 1110 1111 static void free_empty_tables(unsigned long addr, unsigned long end, 1112 unsigned long floor, unsigned long ceiling) 1113 { 1114 unsigned long next; 1115 pgd_t *pgdp, pgd; 1116 1117 do { 1118 next = pgd_addr_end(addr, end); 1119 pgdp = pgd_offset_k(addr); 1120 pgd = READ_ONCE(*pgdp); 1121 if (pgd_none(pgd)) 1122 continue; 1123 1124 WARN_ON(!pgd_present(pgd)); 1125 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1126 } while (addr = next, addr < end); 1127 } 1128 #endif 1129 1130 void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node, 1131 unsigned long addr, unsigned long next) 1132 { 1133 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1134 } 1135 1136 int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node, 1137 unsigned long addr, unsigned long next) 1138 { 1139 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1140 return 1; 1141 } 1142 1143 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1144 struct vmem_altmap *altmap) 1145 { 1146 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1147 1148 if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES)) 1149 return vmemmap_populate_basepages(start, end, node, altmap); 1150 else 1151 return vmemmap_populate_hugepages(start, end, node, altmap); 1152 } 1153 1154 #ifdef CONFIG_MEMORY_HOTPLUG 1155 void vmemmap_free(unsigned long start, unsigned long end, 1156 struct vmem_altmap *altmap) 1157 { 1158 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1159 1160 unmap_hotplug_range(start, end, true, altmap); 1161 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1162 } 1163 #endif /* CONFIG_MEMORY_HOTPLUG */ 1164 1165 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1166 { 1167 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1168 1169 /* Only allow permission changes for now */ 1170 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1171 pud_val(new_pud))) 1172 return 0; 1173 1174 VM_BUG_ON(phys & ~PUD_MASK); 1175 set_pud(pudp, new_pud); 1176 return 1; 1177 } 1178 1179 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1180 { 1181 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1182 1183 /* Only allow permission changes for now */ 1184 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1185 pmd_val(new_pmd))) 1186 return 0; 1187 1188 VM_BUG_ON(phys & ~PMD_MASK); 1189 set_pmd(pmdp, new_pmd); 1190 return 1; 1191 } 1192 1193 int pud_clear_huge(pud_t *pudp) 1194 { 1195 if (!pud_sect(READ_ONCE(*pudp))) 1196 return 0; 1197 pud_clear(pudp); 1198 return 1; 1199 } 1200 1201 int pmd_clear_huge(pmd_t *pmdp) 1202 { 1203 if (!pmd_sect(READ_ONCE(*pmdp))) 1204 return 0; 1205 pmd_clear(pmdp); 1206 return 1; 1207 } 1208 1209 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1210 { 1211 pte_t *table; 1212 pmd_t pmd; 1213 1214 pmd = READ_ONCE(*pmdp); 1215 1216 if (!pmd_table(pmd)) { 1217 VM_WARN_ON(1); 1218 return 1; 1219 } 1220 1221 table = pte_offset_kernel(pmdp, addr); 1222 pmd_clear(pmdp); 1223 __flush_tlb_kernel_pgtable(addr); 1224 pte_free_kernel(NULL, table); 1225 return 1; 1226 } 1227 1228 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1229 { 1230 pmd_t *table; 1231 pmd_t *pmdp; 1232 pud_t pud; 1233 unsigned long next, end; 1234 1235 pud = READ_ONCE(*pudp); 1236 1237 if (!pud_table(pud)) { 1238 VM_WARN_ON(1); 1239 return 1; 1240 } 1241 1242 table = pmd_offset(pudp, addr); 1243 pmdp = table; 1244 next = addr; 1245 end = addr + PUD_SIZE; 1246 do { 1247 pmd_free_pte_page(pmdp, next); 1248 } while (pmdp++, next += PMD_SIZE, next != end); 1249 1250 pud_clear(pudp); 1251 __flush_tlb_kernel_pgtable(addr); 1252 pmd_free(NULL, table); 1253 return 1; 1254 } 1255 1256 #ifdef CONFIG_MEMORY_HOTPLUG 1257 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1258 { 1259 unsigned long end = start + size; 1260 1261 WARN_ON(pgdir != init_mm.pgd); 1262 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1263 1264 unmap_hotplug_range(start, end, false, NULL); 1265 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1266 } 1267 1268 struct range arch_get_mappable_range(void) 1269 { 1270 struct range mhp_range; 1271 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1272 u64 end_linear_pa = __pa(PAGE_END - 1); 1273 1274 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1275 /* 1276 * Check for a wrap, it is possible because of randomized linear 1277 * mapping the start physical address is actually bigger than 1278 * the end physical address. In this case set start to zero 1279 * because [0, end_linear_pa] range must still be able to cover 1280 * all addressable physical addresses. 1281 */ 1282 if (start_linear_pa > end_linear_pa) 1283 start_linear_pa = 0; 1284 } 1285 1286 WARN_ON(start_linear_pa > end_linear_pa); 1287 1288 /* 1289 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1290 * accommodating both its ends but excluding PAGE_END. Max physical 1291 * range which can be mapped inside this linear mapping range, must 1292 * also be derived from its end points. 1293 */ 1294 mhp_range.start = start_linear_pa; 1295 mhp_range.end = end_linear_pa; 1296 1297 return mhp_range; 1298 } 1299 1300 int arch_add_memory(int nid, u64 start, u64 size, 1301 struct mhp_params *params) 1302 { 1303 int ret, flags = NO_EXEC_MAPPINGS; 1304 1305 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1306 1307 if (can_set_direct_map()) 1308 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1309 1310 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1311 size, params->pgprot, __pgd_pgtable_alloc, 1312 flags); 1313 1314 memblock_clear_nomap(start, size); 1315 1316 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1317 params); 1318 if (ret) 1319 __remove_pgd_mapping(swapper_pg_dir, 1320 __phys_to_virt(start), size); 1321 else { 1322 max_pfn = PFN_UP(start + size); 1323 max_low_pfn = max_pfn; 1324 } 1325 1326 return ret; 1327 } 1328 1329 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1330 { 1331 unsigned long start_pfn = start >> PAGE_SHIFT; 1332 unsigned long nr_pages = size >> PAGE_SHIFT; 1333 1334 __remove_pages(start_pfn, nr_pages, altmap); 1335 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1336 } 1337 1338 /* 1339 * This memory hotplug notifier helps prevent boot memory from being 1340 * inadvertently removed as it blocks pfn range offlining process in 1341 * __offline_pages(). Hence this prevents both offlining as well as 1342 * removal process for boot memory which is initially always online. 1343 * In future if and when boot memory could be removed, this notifier 1344 * should be dropped and free_hotplug_page_range() should handle any 1345 * reserved pages allocated during boot. 1346 */ 1347 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1348 unsigned long action, void *data) 1349 { 1350 struct mem_section *ms; 1351 struct memory_notify *arg = data; 1352 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1353 unsigned long pfn = arg->start_pfn; 1354 1355 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1356 return NOTIFY_OK; 1357 1358 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1359 unsigned long start = PFN_PHYS(pfn); 1360 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1361 1362 ms = __pfn_to_section(pfn); 1363 if (!early_section(ms)) 1364 continue; 1365 1366 if (action == MEM_GOING_OFFLINE) { 1367 /* 1368 * Boot memory removal is not supported. Prevent 1369 * it via blocking any attempted offline request 1370 * for the boot memory and just report it. 1371 */ 1372 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1373 return NOTIFY_BAD; 1374 } else if (action == MEM_OFFLINE) { 1375 /* 1376 * This should have never happened. Boot memory 1377 * offlining should have been prevented by this 1378 * very notifier. Probably some memory removal 1379 * procedure might have changed which would then 1380 * require further debug. 1381 */ 1382 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1383 1384 /* 1385 * Core memory hotplug does not process a return 1386 * code from the notifier for MEM_OFFLINE events. 1387 * The error condition has been reported. Return 1388 * from here as if ignored. 1389 */ 1390 return NOTIFY_DONE; 1391 } 1392 } 1393 return NOTIFY_OK; 1394 } 1395 1396 static struct notifier_block prevent_bootmem_remove_nb = { 1397 .notifier_call = prevent_bootmem_remove_notifier, 1398 }; 1399 1400 /* 1401 * This ensures that boot memory sections on the platform are online 1402 * from early boot. Memory sections could not be prevented from being 1403 * offlined, unless for some reason they are not online to begin with. 1404 * This helps validate the basic assumption on which the above memory 1405 * event notifier works to prevent boot memory section offlining and 1406 * its possible removal. 1407 */ 1408 static void validate_bootmem_online(void) 1409 { 1410 phys_addr_t start, end, addr; 1411 struct mem_section *ms; 1412 u64 i; 1413 1414 /* 1415 * Scanning across all memblock might be expensive 1416 * on some big memory systems. Hence enable this 1417 * validation only with DEBUG_VM. 1418 */ 1419 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1420 return; 1421 1422 for_each_mem_range(i, &start, &end) { 1423 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1424 ms = __pfn_to_section(PHYS_PFN(addr)); 1425 1426 /* 1427 * All memory ranges in the system at this point 1428 * should have been marked as early sections. 1429 */ 1430 WARN_ON(!early_section(ms)); 1431 1432 /* 1433 * Memory notifier mechanism here to prevent boot 1434 * memory offlining depends on the fact that each 1435 * early section memory on the system is initially 1436 * online. Otherwise a given memory section which 1437 * is already offline will be overlooked and can 1438 * be removed completely. Call out such sections. 1439 */ 1440 if (!online_section(ms)) 1441 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1442 addr, addr + (1UL << PA_SECTION_SHIFT)); 1443 } 1444 } 1445 } 1446 1447 static int __init prevent_bootmem_remove_init(void) 1448 { 1449 int ret = 0; 1450 1451 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1452 return ret; 1453 1454 validate_bootmem_online(); 1455 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1456 if (ret) 1457 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1458 1459 return ret; 1460 } 1461 early_initcall(prevent_bootmem_remove_init); 1462 #endif 1463 1464 pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) 1465 { 1466 if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) && 1467 cpus_have_const_cap(ARM64_WORKAROUND_2645198)) { 1468 /* 1469 * Break-before-make (BBM) is required for all user space mappings 1470 * when the permission changes from executable to non-executable 1471 * in cases where cpu is affected with errata #2645198. 1472 */ 1473 if (pte_user_exec(READ_ONCE(*ptep))) 1474 return ptep_clear_flush(vma, addr, ptep); 1475 } 1476 return ptep_get_and_clear(vma->vm_mm, addr, ptep); 1477 } 1478 1479 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, 1480 pte_t old_pte, pte_t pte) 1481 { 1482 set_pte_at(vma->vm_mm, addr, ptep, pte); 1483 } 1484