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 u64 kimage_voffset __ro_after_init; 49 EXPORT_SYMBOL(kimage_voffset); 50 51 u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 }; 52 53 static bool rodata_is_rw __ro_after_init = true; 54 55 /* 56 * The booting CPU updates the failed status @__early_cpu_boot_status, 57 * with MMU turned off. 58 */ 59 long __section(".mmuoff.data.write") __early_cpu_boot_status; 60 61 /* 62 * Empty_zero_page is a special page that is used for zero-initialized data 63 * and COW. 64 */ 65 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 66 EXPORT_SYMBOL(empty_zero_page); 67 68 static DEFINE_SPINLOCK(swapper_pgdir_lock); 69 static DEFINE_MUTEX(fixmap_lock); 70 71 void noinstr set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 72 { 73 pgd_t *fixmap_pgdp; 74 75 /* 76 * Don't bother with the fixmap if swapper_pg_dir is still mapped 77 * writable in the kernel mapping. 78 */ 79 if (rodata_is_rw) { 80 WRITE_ONCE(*pgdp, pgd); 81 dsb(ishst); 82 isb(); 83 return; 84 } 85 86 spin_lock(&swapper_pgdir_lock); 87 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 88 WRITE_ONCE(*fixmap_pgdp, pgd); 89 /* 90 * We need dsb(ishst) here to ensure the page-table-walker sees 91 * our new entry before set_p?d() returns. The fixmap's 92 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 93 */ 94 pgd_clear_fixmap(); 95 spin_unlock(&swapper_pgdir_lock); 96 } 97 98 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 99 unsigned long size, pgprot_t vma_prot) 100 { 101 if (!pfn_is_map_memory(pfn)) 102 return pgprot_noncached(vma_prot); 103 else if (file->f_flags & O_SYNC) 104 return pgprot_writecombine(vma_prot); 105 return vma_prot; 106 } 107 EXPORT_SYMBOL(phys_mem_access_prot); 108 109 static phys_addr_t __init early_pgtable_alloc(int shift) 110 { 111 phys_addr_t phys; 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 return phys; 119 } 120 121 bool pgattr_change_is_safe(u64 old, u64 new) 122 { 123 /* 124 * The following mapping attributes may be updated in live 125 * kernel mappings without the need for break-before-make. 126 */ 127 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 128 129 /* creating or taking down mappings is always safe */ 130 if (!pte_valid(__pte(old)) || !pte_valid(__pte(new))) 131 return true; 132 133 /* A live entry's pfn should not change */ 134 if (pte_pfn(__pte(old)) != pte_pfn(__pte(new))) 135 return false; 136 137 /* live contiguous mappings may not be manipulated at all */ 138 if ((old | new) & PTE_CONT) 139 return false; 140 141 /* Transitioning from Non-Global to Global is unsafe */ 142 if (old & ~new & PTE_NG) 143 return false; 144 145 /* 146 * Changing the memory type between Normal and Normal-Tagged is safe 147 * since Tagged is considered a permission attribute from the 148 * mismatched attribute aliases perspective. 149 */ 150 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 151 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 152 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 153 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 154 mask |= PTE_ATTRINDX_MASK; 155 156 return ((old ^ new) & ~mask) == 0; 157 } 158 159 static void init_clear_pgtable(void *table) 160 { 161 clear_page(table); 162 163 /* Ensure the zeroing is observed by page table walks. */ 164 dsb(ishst); 165 } 166 167 static void init_pte(pte_t *ptep, unsigned long addr, unsigned long end, 168 phys_addr_t phys, pgprot_t prot) 169 { 170 do { 171 pte_t old_pte = __ptep_get(ptep); 172 173 /* 174 * Required barriers to make this visible to the table walker 175 * are deferred to the end of alloc_init_cont_pte(). 176 */ 177 __set_pte_nosync(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 178 179 /* 180 * After the PTE entry has been populated once, we 181 * only allow updates to the permission attributes. 182 */ 183 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 184 pte_val(__ptep_get(ptep)))); 185 186 phys += PAGE_SIZE; 187 } while (ptep++, addr += PAGE_SIZE, addr != end); 188 } 189 190 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 191 unsigned long end, phys_addr_t phys, 192 pgprot_t prot, 193 phys_addr_t (*pgtable_alloc)(int), 194 int flags) 195 { 196 unsigned long next; 197 pmd_t pmd = READ_ONCE(*pmdp); 198 pte_t *ptep; 199 200 BUG_ON(pmd_sect(pmd)); 201 if (pmd_none(pmd)) { 202 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN; 203 phys_addr_t pte_phys; 204 205 if (flags & NO_EXEC_MAPPINGS) 206 pmdval |= PMD_TABLE_PXN; 207 BUG_ON(!pgtable_alloc); 208 pte_phys = pgtable_alloc(PAGE_SHIFT); 209 ptep = pte_set_fixmap(pte_phys); 210 init_clear_pgtable(ptep); 211 ptep += pte_index(addr); 212 __pmd_populate(pmdp, pte_phys, pmdval); 213 } else { 214 BUG_ON(pmd_bad(pmd)); 215 ptep = pte_set_fixmap_offset(pmdp, addr); 216 } 217 218 do { 219 pgprot_t __prot = prot; 220 221 next = pte_cont_addr_end(addr, end); 222 223 /* use a contiguous mapping if the range is suitably aligned */ 224 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 225 (flags & NO_CONT_MAPPINGS) == 0) 226 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 227 228 init_pte(ptep, addr, next, phys, __prot); 229 230 ptep += pte_index(next) - pte_index(addr); 231 phys += next - addr; 232 } while (addr = next, addr != end); 233 234 /* 235 * Note: barriers and maintenance necessary to clear the fixmap slot 236 * ensure that all previous pgtable writes are visible to the table 237 * walker. 238 */ 239 pte_clear_fixmap(); 240 } 241 242 static void init_pmd(pmd_t *pmdp, unsigned long addr, unsigned long end, 243 phys_addr_t phys, pgprot_t prot, 244 phys_addr_t (*pgtable_alloc)(int), int flags) 245 { 246 unsigned long next; 247 248 do { 249 pmd_t old_pmd = READ_ONCE(*pmdp); 250 251 next = pmd_addr_end(addr, end); 252 253 /* try section mapping first */ 254 if (((addr | next | phys) & ~PMD_MASK) == 0 && 255 (flags & NO_BLOCK_MAPPINGS) == 0) { 256 pmd_set_huge(pmdp, phys, prot); 257 258 /* 259 * After the PMD entry has been populated once, we 260 * only allow updates to the permission attributes. 261 */ 262 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 263 READ_ONCE(pmd_val(*pmdp)))); 264 } else { 265 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 266 pgtable_alloc, flags); 267 268 BUG_ON(pmd_val(old_pmd) != 0 && 269 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 270 } 271 phys += next - addr; 272 } while (pmdp++, addr = next, addr != end); 273 } 274 275 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 276 unsigned long end, phys_addr_t phys, 277 pgprot_t prot, 278 phys_addr_t (*pgtable_alloc)(int), int flags) 279 { 280 unsigned long next; 281 pud_t pud = READ_ONCE(*pudp); 282 pmd_t *pmdp; 283 284 /* 285 * Check for initial section mappings in the pgd/pud. 286 */ 287 BUG_ON(pud_sect(pud)); 288 if (pud_none(pud)) { 289 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN; 290 phys_addr_t pmd_phys; 291 292 if (flags & NO_EXEC_MAPPINGS) 293 pudval |= PUD_TABLE_PXN; 294 BUG_ON(!pgtable_alloc); 295 pmd_phys = pgtable_alloc(PMD_SHIFT); 296 pmdp = pmd_set_fixmap(pmd_phys); 297 init_clear_pgtable(pmdp); 298 pmdp += pmd_index(addr); 299 __pud_populate(pudp, pmd_phys, pudval); 300 } else { 301 BUG_ON(pud_bad(pud)); 302 pmdp = pmd_set_fixmap_offset(pudp, addr); 303 } 304 305 do { 306 pgprot_t __prot = prot; 307 308 next = pmd_cont_addr_end(addr, end); 309 310 /* use a contiguous mapping if the range is suitably aligned */ 311 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 312 (flags & NO_CONT_MAPPINGS) == 0) 313 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 314 315 init_pmd(pmdp, addr, next, phys, __prot, pgtable_alloc, flags); 316 317 pmdp += pmd_index(next) - pmd_index(addr); 318 phys += next - addr; 319 } while (addr = next, addr != end); 320 321 pmd_clear_fixmap(); 322 } 323 324 static void alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, 325 phys_addr_t phys, pgprot_t prot, 326 phys_addr_t (*pgtable_alloc)(int), 327 int flags) 328 { 329 unsigned long next; 330 p4d_t p4d = READ_ONCE(*p4dp); 331 pud_t *pudp; 332 333 if (p4d_none(p4d)) { 334 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN; 335 phys_addr_t pud_phys; 336 337 if (flags & NO_EXEC_MAPPINGS) 338 p4dval |= P4D_TABLE_PXN; 339 BUG_ON(!pgtable_alloc); 340 pud_phys = pgtable_alloc(PUD_SHIFT); 341 pudp = pud_set_fixmap(pud_phys); 342 init_clear_pgtable(pudp); 343 pudp += pud_index(addr); 344 __p4d_populate(p4dp, pud_phys, p4dval); 345 } else { 346 BUG_ON(p4d_bad(p4d)); 347 pudp = pud_set_fixmap_offset(p4dp, addr); 348 } 349 350 do { 351 pud_t old_pud = READ_ONCE(*pudp); 352 353 next = pud_addr_end(addr, end); 354 355 /* 356 * For 4K granule only, attempt to put down a 1GB block 357 */ 358 if (pud_sect_supported() && 359 ((addr | next | phys) & ~PUD_MASK) == 0 && 360 (flags & NO_BLOCK_MAPPINGS) == 0) { 361 pud_set_huge(pudp, phys, prot); 362 363 /* 364 * After the PUD entry has been populated once, we 365 * only allow updates to the permission attributes. 366 */ 367 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 368 READ_ONCE(pud_val(*pudp)))); 369 } else { 370 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 371 pgtable_alloc, flags); 372 373 BUG_ON(pud_val(old_pud) != 0 && 374 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 375 } 376 phys += next - addr; 377 } while (pudp++, addr = next, addr != end); 378 379 pud_clear_fixmap(); 380 } 381 382 static void alloc_init_p4d(pgd_t *pgdp, unsigned long addr, unsigned long end, 383 phys_addr_t phys, pgprot_t prot, 384 phys_addr_t (*pgtable_alloc)(int), 385 int flags) 386 { 387 unsigned long next; 388 pgd_t pgd = READ_ONCE(*pgdp); 389 p4d_t *p4dp; 390 391 if (pgd_none(pgd)) { 392 pgdval_t pgdval = PGD_TYPE_TABLE | PGD_TABLE_UXN; 393 phys_addr_t p4d_phys; 394 395 if (flags & NO_EXEC_MAPPINGS) 396 pgdval |= PGD_TABLE_PXN; 397 BUG_ON(!pgtable_alloc); 398 p4d_phys = pgtable_alloc(P4D_SHIFT); 399 p4dp = p4d_set_fixmap(p4d_phys); 400 init_clear_pgtable(p4dp); 401 p4dp += p4d_index(addr); 402 __pgd_populate(pgdp, p4d_phys, pgdval); 403 } else { 404 BUG_ON(pgd_bad(pgd)); 405 p4dp = p4d_set_fixmap_offset(pgdp, addr); 406 } 407 408 do { 409 p4d_t old_p4d = READ_ONCE(*p4dp); 410 411 next = p4d_addr_end(addr, end); 412 413 alloc_init_pud(p4dp, addr, next, phys, prot, 414 pgtable_alloc, flags); 415 416 BUG_ON(p4d_val(old_p4d) != 0 && 417 p4d_val(old_p4d) != READ_ONCE(p4d_val(*p4dp))); 418 419 phys += next - addr; 420 } while (p4dp++, addr = next, addr != end); 421 422 p4d_clear_fixmap(); 423 } 424 425 static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, 426 unsigned long virt, phys_addr_t size, 427 pgprot_t prot, 428 phys_addr_t (*pgtable_alloc)(int), 429 int flags) 430 { 431 unsigned long addr, end, next; 432 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 433 434 /* 435 * If the virtual and physical address don't have the same offset 436 * within a page, we cannot map the region as the caller expects. 437 */ 438 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 439 return; 440 441 phys &= PAGE_MASK; 442 addr = virt & PAGE_MASK; 443 end = PAGE_ALIGN(virt + size); 444 445 do { 446 next = pgd_addr_end(addr, end); 447 alloc_init_p4d(pgdp, addr, next, phys, prot, pgtable_alloc, 448 flags); 449 phys += next - addr; 450 } while (pgdp++, addr = next, addr != end); 451 } 452 453 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 454 unsigned long virt, phys_addr_t size, 455 pgprot_t prot, 456 phys_addr_t (*pgtable_alloc)(int), 457 int flags) 458 { 459 mutex_lock(&fixmap_lock); 460 __create_pgd_mapping_locked(pgdir, phys, virt, size, prot, 461 pgtable_alloc, flags); 462 mutex_unlock(&fixmap_lock); 463 } 464 465 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 466 extern __alias(__create_pgd_mapping_locked) 467 void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, 468 phys_addr_t size, pgprot_t prot, 469 phys_addr_t (*pgtable_alloc)(int), int flags); 470 #endif 471 472 static phys_addr_t __pgd_pgtable_alloc(int shift) 473 { 474 /* Page is zeroed by init_clear_pgtable() so don't duplicate effort. */ 475 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL & ~__GFP_ZERO); 476 477 BUG_ON(!ptr); 478 return __pa(ptr); 479 } 480 481 static phys_addr_t pgd_pgtable_alloc(int shift) 482 { 483 phys_addr_t pa = __pgd_pgtable_alloc(shift); 484 struct ptdesc *ptdesc = page_ptdesc(phys_to_page(pa)); 485 486 /* 487 * Call proper page table ctor in case later we need to 488 * call core mm functions like apply_to_page_range() on 489 * this pre-allocated page table. 490 * 491 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 492 * folded, and if so pagetable_pte_ctor() becomes nop. 493 */ 494 if (shift == PAGE_SHIFT) 495 BUG_ON(!pagetable_pte_ctor(ptdesc)); 496 else if (shift == PMD_SHIFT) 497 BUG_ON(!pagetable_pmd_ctor(ptdesc)); 498 499 return pa; 500 } 501 502 /* 503 * This function can only be used to modify existing table entries, 504 * without allocating new levels of table. Note that this permits the 505 * creation of new section or page entries. 506 */ 507 void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 508 phys_addr_t size, pgprot_t prot) 509 { 510 if (virt < PAGE_OFFSET) { 511 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 512 &phys, virt); 513 return; 514 } 515 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 516 NO_CONT_MAPPINGS); 517 } 518 519 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 520 unsigned long virt, phys_addr_t size, 521 pgprot_t prot, bool page_mappings_only) 522 { 523 int flags = 0; 524 525 BUG_ON(mm == &init_mm); 526 527 if (page_mappings_only) 528 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 529 530 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 531 pgd_pgtable_alloc, flags); 532 } 533 534 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 535 phys_addr_t size, pgprot_t prot) 536 { 537 if (virt < PAGE_OFFSET) { 538 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 539 &phys, virt); 540 return; 541 } 542 543 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 544 NO_CONT_MAPPINGS); 545 546 /* flush the TLBs after updating live kernel mappings */ 547 flush_tlb_kernel_range(virt, virt + size); 548 } 549 550 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 551 phys_addr_t end, pgprot_t prot, int flags) 552 { 553 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 554 prot, early_pgtable_alloc, flags); 555 } 556 557 void __init mark_linear_text_alias_ro(void) 558 { 559 /* 560 * Remove the write permissions from the linear alias of .text/.rodata 561 */ 562 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext), 563 (unsigned long)__init_begin - (unsigned long)_stext, 564 PAGE_KERNEL_RO); 565 } 566 567 #ifdef CONFIG_KFENCE 568 569 bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL; 570 571 /* early_param() will be parsed before map_mem() below. */ 572 static int __init parse_kfence_early_init(char *arg) 573 { 574 int val; 575 576 if (get_option(&arg, &val)) 577 kfence_early_init = !!val; 578 return 0; 579 } 580 early_param("kfence.sample_interval", parse_kfence_early_init); 581 582 static phys_addr_t __init arm64_kfence_alloc_pool(void) 583 { 584 phys_addr_t kfence_pool; 585 586 if (!kfence_early_init) 587 return 0; 588 589 kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); 590 if (!kfence_pool) { 591 pr_err("failed to allocate kfence pool\n"); 592 kfence_early_init = false; 593 return 0; 594 } 595 596 /* Temporarily mark as NOMAP. */ 597 memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); 598 599 return kfence_pool; 600 } 601 602 static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) 603 { 604 if (!kfence_pool) 605 return; 606 607 /* KFENCE pool needs page-level mapping. */ 608 __map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE, 609 pgprot_tagged(PAGE_KERNEL), 610 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 611 memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); 612 __kfence_pool = phys_to_virt(kfence_pool); 613 } 614 #else /* CONFIG_KFENCE */ 615 616 static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; } 617 static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { } 618 619 #endif /* CONFIG_KFENCE */ 620 621 static void __init map_mem(pgd_t *pgdp) 622 { 623 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 624 phys_addr_t kernel_start = __pa_symbol(_stext); 625 phys_addr_t kernel_end = __pa_symbol(__init_begin); 626 phys_addr_t start, end; 627 phys_addr_t early_kfence_pool; 628 int flags = NO_EXEC_MAPPINGS; 629 u64 i; 630 631 /* 632 * Setting hierarchical PXNTable attributes on table entries covering 633 * the linear region is only possible if it is guaranteed that no table 634 * entries at any level are being shared between the linear region and 635 * the vmalloc region. Check whether this is true for the PGD level, in 636 * which case it is guaranteed to be true for all other levels as well. 637 * (Unless we are running with support for LPA2, in which case the 638 * entire reduced VA space is covered by a single pgd_t which will have 639 * been populated without the PXNTable attribute by the time we get here.) 640 */ 641 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end) && 642 pgd_index(_PAGE_OFFSET(VA_BITS_MIN)) != PTRS_PER_PGD - 1); 643 644 early_kfence_pool = arm64_kfence_alloc_pool(); 645 646 if (can_set_direct_map()) 647 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 648 649 /* 650 * Take care not to create a writable alias for the 651 * read-only text and rodata sections of the kernel image. 652 * So temporarily mark them as NOMAP to skip mappings in 653 * the following for-loop 654 */ 655 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 656 657 /* map all the memory banks */ 658 for_each_mem_range(i, &start, &end) { 659 if (start >= end) 660 break; 661 /* 662 * The linear map must allow allocation tags reading/writing 663 * if MTE is present. Otherwise, it has the same attributes as 664 * PAGE_KERNEL. 665 */ 666 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 667 flags); 668 } 669 670 /* 671 * Map the linear alias of the [_stext, __init_begin) interval 672 * as non-executable now, and remove the write permission in 673 * mark_linear_text_alias_ro() below (which will be called after 674 * alternative patching has completed). This makes the contents 675 * of the region accessible to subsystems such as hibernate, 676 * but protects it from inadvertent modification or execution. 677 * Note that contiguous mappings cannot be remapped in this way, 678 * so we should avoid them here. 679 */ 680 __map_memblock(pgdp, kernel_start, kernel_end, 681 PAGE_KERNEL, NO_CONT_MAPPINGS); 682 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 683 arm64_kfence_map_pool(early_kfence_pool, pgdp); 684 } 685 686 void mark_rodata_ro(void) 687 { 688 unsigned long section_size; 689 690 /* 691 * mark .rodata as read only. Use __init_begin rather than __end_rodata 692 * to cover NOTES and EXCEPTION_TABLE. 693 */ 694 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 695 WRITE_ONCE(rodata_is_rw, false); 696 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 697 section_size, PAGE_KERNEL_RO); 698 } 699 700 static void __init declare_vma(struct vm_struct *vma, 701 void *va_start, void *va_end, 702 unsigned long vm_flags) 703 { 704 phys_addr_t pa_start = __pa_symbol(va_start); 705 unsigned long size = va_end - va_start; 706 707 BUG_ON(!PAGE_ALIGNED(pa_start)); 708 BUG_ON(!PAGE_ALIGNED(size)); 709 710 if (!(vm_flags & VM_NO_GUARD)) 711 size += PAGE_SIZE; 712 713 vma->addr = va_start; 714 vma->phys_addr = pa_start; 715 vma->size = size; 716 vma->flags = VM_MAP | vm_flags; 717 vma->caller = __builtin_return_address(0); 718 719 vm_area_add_early(vma); 720 } 721 722 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 723 static pgprot_t kernel_exec_prot(void) 724 { 725 return rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 726 } 727 728 static int __init map_entry_trampoline(void) 729 { 730 int i; 731 732 if (!arm64_kernel_unmapped_at_el0()) 733 return 0; 734 735 pgprot_t prot = kernel_exec_prot(); 736 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 737 738 /* The trampoline is always mapped and can therefore be global */ 739 pgprot_val(prot) &= ~PTE_NG; 740 741 /* Map only the text into the trampoline page table */ 742 memset(tramp_pg_dir, 0, PGD_SIZE); 743 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 744 entry_tramp_text_size(), prot, 745 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 746 747 /* Map both the text and data into the kernel page table */ 748 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 749 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 750 pa_start + i * PAGE_SIZE, prot); 751 752 if (IS_ENABLED(CONFIG_RELOCATABLE)) 753 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 754 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 755 756 return 0; 757 } 758 core_initcall(map_entry_trampoline); 759 #endif 760 761 /* 762 * Declare the VMA areas for the kernel 763 */ 764 static void __init declare_kernel_vmas(void) 765 { 766 static struct vm_struct vmlinux_seg[KERNEL_SEGMENT_COUNT]; 767 768 declare_vma(&vmlinux_seg[0], _stext, _etext, VM_NO_GUARD); 769 declare_vma(&vmlinux_seg[1], __start_rodata, __inittext_begin, VM_NO_GUARD); 770 declare_vma(&vmlinux_seg[2], __inittext_begin, __inittext_end, VM_NO_GUARD); 771 declare_vma(&vmlinux_seg[3], __initdata_begin, __initdata_end, VM_NO_GUARD); 772 declare_vma(&vmlinux_seg[4], _data, _end, 0); 773 } 774 775 void __pi_map_range(u64 *pgd, u64 start, u64 end, u64 pa, pgprot_t prot, 776 int level, pte_t *tbl, bool may_use_cont, u64 va_offset); 777 778 static u8 idmap_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init, 779 kpti_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init; 780 781 static void __init create_idmap(void) 782 { 783 u64 start = __pa_symbol(__idmap_text_start); 784 u64 end = __pa_symbol(__idmap_text_end); 785 u64 ptep = __pa_symbol(idmap_ptes); 786 787 __pi_map_range(&ptep, start, end, start, PAGE_KERNEL_ROX, 788 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false, 789 __phys_to_virt(ptep) - ptep); 790 791 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) && !arm64_use_ng_mappings) { 792 extern u32 __idmap_kpti_flag; 793 u64 pa = __pa_symbol(&__idmap_kpti_flag); 794 795 /* 796 * The KPTI G-to-nG conversion code needs a read-write mapping 797 * of its synchronization flag in the ID map. 798 */ 799 ptep = __pa_symbol(kpti_ptes); 800 __pi_map_range(&ptep, pa, pa + sizeof(u32), pa, PAGE_KERNEL, 801 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false, 802 __phys_to_virt(ptep) - ptep); 803 } 804 } 805 806 void __init paging_init(void) 807 { 808 map_mem(swapper_pg_dir); 809 810 memblock_allow_resize(); 811 812 create_idmap(); 813 declare_kernel_vmas(); 814 } 815 816 #ifdef CONFIG_MEMORY_HOTPLUG 817 static void free_hotplug_page_range(struct page *page, size_t size, 818 struct vmem_altmap *altmap) 819 { 820 if (altmap) { 821 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 822 } else { 823 WARN_ON(PageReserved(page)); 824 free_pages((unsigned long)page_address(page), get_order(size)); 825 } 826 } 827 828 static void free_hotplug_pgtable_page(struct page *page) 829 { 830 free_hotplug_page_range(page, PAGE_SIZE, NULL); 831 } 832 833 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 834 unsigned long floor, unsigned long ceiling, 835 unsigned long mask) 836 { 837 start &= mask; 838 if (start < floor) 839 return false; 840 841 if (ceiling) { 842 ceiling &= mask; 843 if (!ceiling) 844 return false; 845 } 846 847 if (end - 1 > ceiling - 1) 848 return false; 849 return true; 850 } 851 852 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 853 unsigned long end, bool free_mapped, 854 struct vmem_altmap *altmap) 855 { 856 pte_t *ptep, pte; 857 858 do { 859 ptep = pte_offset_kernel(pmdp, addr); 860 pte = __ptep_get(ptep); 861 if (pte_none(pte)) 862 continue; 863 864 WARN_ON(!pte_present(pte)); 865 __pte_clear(&init_mm, addr, ptep); 866 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 867 if (free_mapped) 868 free_hotplug_page_range(pte_page(pte), 869 PAGE_SIZE, altmap); 870 } while (addr += PAGE_SIZE, addr < end); 871 } 872 873 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 874 unsigned long end, bool free_mapped, 875 struct vmem_altmap *altmap) 876 { 877 unsigned long next; 878 pmd_t *pmdp, pmd; 879 880 do { 881 next = pmd_addr_end(addr, end); 882 pmdp = pmd_offset(pudp, addr); 883 pmd = READ_ONCE(*pmdp); 884 if (pmd_none(pmd)) 885 continue; 886 887 WARN_ON(!pmd_present(pmd)); 888 if (pmd_sect(pmd)) { 889 pmd_clear(pmdp); 890 891 /* 892 * One TLBI should be sufficient here as the PMD_SIZE 893 * range is mapped with a single block entry. 894 */ 895 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 896 if (free_mapped) 897 free_hotplug_page_range(pmd_page(pmd), 898 PMD_SIZE, altmap); 899 continue; 900 } 901 WARN_ON(!pmd_table(pmd)); 902 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 903 } while (addr = next, addr < end); 904 } 905 906 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 907 unsigned long end, bool free_mapped, 908 struct vmem_altmap *altmap) 909 { 910 unsigned long next; 911 pud_t *pudp, pud; 912 913 do { 914 next = pud_addr_end(addr, end); 915 pudp = pud_offset(p4dp, addr); 916 pud = READ_ONCE(*pudp); 917 if (pud_none(pud)) 918 continue; 919 920 WARN_ON(!pud_present(pud)); 921 if (pud_sect(pud)) { 922 pud_clear(pudp); 923 924 /* 925 * One TLBI should be sufficient here as the PUD_SIZE 926 * range is mapped with a single block entry. 927 */ 928 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 929 if (free_mapped) 930 free_hotplug_page_range(pud_page(pud), 931 PUD_SIZE, altmap); 932 continue; 933 } 934 WARN_ON(!pud_table(pud)); 935 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 936 } while (addr = next, addr < end); 937 } 938 939 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 940 unsigned long end, bool free_mapped, 941 struct vmem_altmap *altmap) 942 { 943 unsigned long next; 944 p4d_t *p4dp, p4d; 945 946 do { 947 next = p4d_addr_end(addr, end); 948 p4dp = p4d_offset(pgdp, addr); 949 p4d = READ_ONCE(*p4dp); 950 if (p4d_none(p4d)) 951 continue; 952 953 WARN_ON(!p4d_present(p4d)); 954 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 955 } while (addr = next, addr < end); 956 } 957 958 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 959 bool free_mapped, struct vmem_altmap *altmap) 960 { 961 unsigned long next; 962 pgd_t *pgdp, pgd; 963 964 /* 965 * altmap can only be used as vmemmap mapping backing memory. 966 * In case the backing memory itself is not being freed, then 967 * altmap is irrelevant. Warn about this inconsistency when 968 * encountered. 969 */ 970 WARN_ON(!free_mapped && altmap); 971 972 do { 973 next = pgd_addr_end(addr, end); 974 pgdp = pgd_offset_k(addr); 975 pgd = READ_ONCE(*pgdp); 976 if (pgd_none(pgd)) 977 continue; 978 979 WARN_ON(!pgd_present(pgd)); 980 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 981 } while (addr = next, addr < end); 982 } 983 984 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 985 unsigned long end, unsigned long floor, 986 unsigned long ceiling) 987 { 988 pte_t *ptep, pte; 989 unsigned long i, start = addr; 990 991 do { 992 ptep = pte_offset_kernel(pmdp, addr); 993 pte = __ptep_get(ptep); 994 995 /* 996 * This is just a sanity check here which verifies that 997 * pte clearing has been done by earlier unmap loops. 998 */ 999 WARN_ON(!pte_none(pte)); 1000 } while (addr += PAGE_SIZE, addr < end); 1001 1002 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1003 return; 1004 1005 /* 1006 * Check whether we can free the pte page if the rest of the 1007 * entries are empty. Overlap with other regions have been 1008 * handled by the floor/ceiling check. 1009 */ 1010 ptep = pte_offset_kernel(pmdp, 0UL); 1011 for (i = 0; i < PTRS_PER_PTE; i++) { 1012 if (!pte_none(__ptep_get(&ptep[i]))) 1013 return; 1014 } 1015 1016 pmd_clear(pmdp); 1017 __flush_tlb_kernel_pgtable(start); 1018 free_hotplug_pgtable_page(virt_to_page(ptep)); 1019 } 1020 1021 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1022 unsigned long end, unsigned long floor, 1023 unsigned long ceiling) 1024 { 1025 pmd_t *pmdp, pmd; 1026 unsigned long i, next, start = addr; 1027 1028 do { 1029 next = pmd_addr_end(addr, end); 1030 pmdp = pmd_offset(pudp, addr); 1031 pmd = READ_ONCE(*pmdp); 1032 if (pmd_none(pmd)) 1033 continue; 1034 1035 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1036 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1037 } while (addr = next, addr < end); 1038 1039 if (CONFIG_PGTABLE_LEVELS <= 2) 1040 return; 1041 1042 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1043 return; 1044 1045 /* 1046 * Check whether we can free the pmd page if the rest of the 1047 * entries are empty. Overlap with other regions have been 1048 * handled by the floor/ceiling check. 1049 */ 1050 pmdp = pmd_offset(pudp, 0UL); 1051 for (i = 0; i < PTRS_PER_PMD; i++) { 1052 if (!pmd_none(READ_ONCE(pmdp[i]))) 1053 return; 1054 } 1055 1056 pud_clear(pudp); 1057 __flush_tlb_kernel_pgtable(start); 1058 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1059 } 1060 1061 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1062 unsigned long end, unsigned long floor, 1063 unsigned long ceiling) 1064 { 1065 pud_t *pudp, pud; 1066 unsigned long i, next, start = addr; 1067 1068 do { 1069 next = pud_addr_end(addr, end); 1070 pudp = pud_offset(p4dp, addr); 1071 pud = READ_ONCE(*pudp); 1072 if (pud_none(pud)) 1073 continue; 1074 1075 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1076 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1077 } while (addr = next, addr < end); 1078 1079 if (!pgtable_l4_enabled()) 1080 return; 1081 1082 if (!pgtable_range_aligned(start, end, floor, ceiling, P4D_MASK)) 1083 return; 1084 1085 /* 1086 * Check whether we can free the pud page if the rest of the 1087 * entries are empty. Overlap with other regions have been 1088 * handled by the floor/ceiling check. 1089 */ 1090 pudp = pud_offset(p4dp, 0UL); 1091 for (i = 0; i < PTRS_PER_PUD; i++) { 1092 if (!pud_none(READ_ONCE(pudp[i]))) 1093 return; 1094 } 1095 1096 p4d_clear(p4dp); 1097 __flush_tlb_kernel_pgtable(start); 1098 free_hotplug_pgtable_page(virt_to_page(pudp)); 1099 } 1100 1101 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1102 unsigned long end, unsigned long floor, 1103 unsigned long ceiling) 1104 { 1105 p4d_t *p4dp, p4d; 1106 unsigned long i, next, start = addr; 1107 1108 do { 1109 next = p4d_addr_end(addr, end); 1110 p4dp = p4d_offset(pgdp, addr); 1111 p4d = READ_ONCE(*p4dp); 1112 if (p4d_none(p4d)) 1113 continue; 1114 1115 WARN_ON(!p4d_present(p4d)); 1116 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1117 } while (addr = next, addr < end); 1118 1119 if (!pgtable_l5_enabled()) 1120 return; 1121 1122 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1123 return; 1124 1125 /* 1126 * Check whether we can free the p4d page if the rest of the 1127 * entries are empty. Overlap with other regions have been 1128 * handled by the floor/ceiling check. 1129 */ 1130 p4dp = p4d_offset(pgdp, 0UL); 1131 for (i = 0; i < PTRS_PER_P4D; i++) { 1132 if (!p4d_none(READ_ONCE(p4dp[i]))) 1133 return; 1134 } 1135 1136 pgd_clear(pgdp); 1137 __flush_tlb_kernel_pgtable(start); 1138 free_hotplug_pgtable_page(virt_to_page(p4dp)); 1139 } 1140 1141 static void free_empty_tables(unsigned long addr, unsigned long end, 1142 unsigned long floor, unsigned long ceiling) 1143 { 1144 unsigned long next; 1145 pgd_t *pgdp, pgd; 1146 1147 do { 1148 next = pgd_addr_end(addr, end); 1149 pgdp = pgd_offset_k(addr); 1150 pgd = READ_ONCE(*pgdp); 1151 if (pgd_none(pgd)) 1152 continue; 1153 1154 WARN_ON(!pgd_present(pgd)); 1155 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1156 } while (addr = next, addr < end); 1157 } 1158 #endif 1159 1160 void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node, 1161 unsigned long addr, unsigned long next) 1162 { 1163 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1164 } 1165 1166 int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node, 1167 unsigned long addr, unsigned long next) 1168 { 1169 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1170 return 1; 1171 } 1172 1173 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1174 struct vmem_altmap *altmap) 1175 { 1176 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1177 1178 if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES)) 1179 return vmemmap_populate_basepages(start, end, node, altmap); 1180 else 1181 return vmemmap_populate_hugepages(start, end, node, altmap); 1182 } 1183 1184 #ifdef CONFIG_MEMORY_HOTPLUG 1185 void vmemmap_free(unsigned long start, unsigned long end, 1186 struct vmem_altmap *altmap) 1187 { 1188 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1189 1190 unmap_hotplug_range(start, end, true, altmap); 1191 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1192 } 1193 #endif /* CONFIG_MEMORY_HOTPLUG */ 1194 1195 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1196 { 1197 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1198 1199 /* Only allow permission changes for now */ 1200 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1201 pud_val(new_pud))) 1202 return 0; 1203 1204 VM_BUG_ON(phys & ~PUD_MASK); 1205 set_pud(pudp, new_pud); 1206 return 1; 1207 } 1208 1209 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1210 { 1211 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1212 1213 /* Only allow permission changes for now */ 1214 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1215 pmd_val(new_pmd))) 1216 return 0; 1217 1218 VM_BUG_ON(phys & ~PMD_MASK); 1219 set_pmd(pmdp, new_pmd); 1220 return 1; 1221 } 1222 1223 #ifndef __PAGETABLE_P4D_FOLDED 1224 void p4d_clear_huge(p4d_t *p4dp) 1225 { 1226 } 1227 #endif 1228 1229 int pud_clear_huge(pud_t *pudp) 1230 { 1231 if (!pud_sect(READ_ONCE(*pudp))) 1232 return 0; 1233 pud_clear(pudp); 1234 return 1; 1235 } 1236 1237 int pmd_clear_huge(pmd_t *pmdp) 1238 { 1239 if (!pmd_sect(READ_ONCE(*pmdp))) 1240 return 0; 1241 pmd_clear(pmdp); 1242 return 1; 1243 } 1244 1245 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1246 { 1247 pte_t *table; 1248 pmd_t pmd; 1249 1250 pmd = READ_ONCE(*pmdp); 1251 1252 if (!pmd_table(pmd)) { 1253 VM_WARN_ON(1); 1254 return 1; 1255 } 1256 1257 table = pte_offset_kernel(pmdp, addr); 1258 pmd_clear(pmdp); 1259 __flush_tlb_kernel_pgtable(addr); 1260 pte_free_kernel(NULL, table); 1261 return 1; 1262 } 1263 1264 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1265 { 1266 pmd_t *table; 1267 pmd_t *pmdp; 1268 pud_t pud; 1269 unsigned long next, end; 1270 1271 pud = READ_ONCE(*pudp); 1272 1273 if (!pud_table(pud)) { 1274 VM_WARN_ON(1); 1275 return 1; 1276 } 1277 1278 table = pmd_offset(pudp, addr); 1279 pmdp = table; 1280 next = addr; 1281 end = addr + PUD_SIZE; 1282 do { 1283 pmd_free_pte_page(pmdp, next); 1284 } while (pmdp++, next += PMD_SIZE, next != end); 1285 1286 pud_clear(pudp); 1287 __flush_tlb_kernel_pgtable(addr); 1288 pmd_free(NULL, table); 1289 return 1; 1290 } 1291 1292 #ifdef CONFIG_MEMORY_HOTPLUG 1293 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1294 { 1295 unsigned long end = start + size; 1296 1297 WARN_ON(pgdir != init_mm.pgd); 1298 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1299 1300 unmap_hotplug_range(start, end, false, NULL); 1301 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1302 } 1303 1304 struct range arch_get_mappable_range(void) 1305 { 1306 struct range mhp_range; 1307 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1308 u64 end_linear_pa = __pa(PAGE_END - 1); 1309 1310 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1311 /* 1312 * Check for a wrap, it is possible because of randomized linear 1313 * mapping the start physical address is actually bigger than 1314 * the end physical address. In this case set start to zero 1315 * because [0, end_linear_pa] range must still be able to cover 1316 * all addressable physical addresses. 1317 */ 1318 if (start_linear_pa > end_linear_pa) 1319 start_linear_pa = 0; 1320 } 1321 1322 WARN_ON(start_linear_pa > end_linear_pa); 1323 1324 /* 1325 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1326 * accommodating both its ends but excluding PAGE_END. Max physical 1327 * range which can be mapped inside this linear mapping range, must 1328 * also be derived from its end points. 1329 */ 1330 mhp_range.start = start_linear_pa; 1331 mhp_range.end = end_linear_pa; 1332 1333 return mhp_range; 1334 } 1335 1336 int arch_add_memory(int nid, u64 start, u64 size, 1337 struct mhp_params *params) 1338 { 1339 int ret, flags = NO_EXEC_MAPPINGS; 1340 1341 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1342 1343 if (can_set_direct_map()) 1344 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1345 1346 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1347 size, params->pgprot, __pgd_pgtable_alloc, 1348 flags); 1349 1350 memblock_clear_nomap(start, size); 1351 1352 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1353 params); 1354 if (ret) 1355 __remove_pgd_mapping(swapper_pg_dir, 1356 __phys_to_virt(start), size); 1357 else { 1358 max_pfn = PFN_UP(start + size); 1359 max_low_pfn = max_pfn; 1360 } 1361 1362 return ret; 1363 } 1364 1365 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1366 { 1367 unsigned long start_pfn = start >> PAGE_SHIFT; 1368 unsigned long nr_pages = size >> PAGE_SHIFT; 1369 1370 __remove_pages(start_pfn, nr_pages, altmap); 1371 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1372 } 1373 1374 /* 1375 * This memory hotplug notifier helps prevent boot memory from being 1376 * inadvertently removed as it blocks pfn range offlining process in 1377 * __offline_pages(). Hence this prevents both offlining as well as 1378 * removal process for boot memory which is initially always online. 1379 * In future if and when boot memory could be removed, this notifier 1380 * should be dropped and free_hotplug_page_range() should handle any 1381 * reserved pages allocated during boot. 1382 */ 1383 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1384 unsigned long action, void *data) 1385 { 1386 struct mem_section *ms; 1387 struct memory_notify *arg = data; 1388 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1389 unsigned long pfn = arg->start_pfn; 1390 1391 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1392 return NOTIFY_OK; 1393 1394 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1395 unsigned long start = PFN_PHYS(pfn); 1396 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1397 1398 ms = __pfn_to_section(pfn); 1399 if (!early_section(ms)) 1400 continue; 1401 1402 if (action == MEM_GOING_OFFLINE) { 1403 /* 1404 * Boot memory removal is not supported. Prevent 1405 * it via blocking any attempted offline request 1406 * for the boot memory and just report it. 1407 */ 1408 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1409 return NOTIFY_BAD; 1410 } else if (action == MEM_OFFLINE) { 1411 /* 1412 * This should have never happened. Boot memory 1413 * offlining should have been prevented by this 1414 * very notifier. Probably some memory removal 1415 * procedure might have changed which would then 1416 * require further debug. 1417 */ 1418 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1419 1420 /* 1421 * Core memory hotplug does not process a return 1422 * code from the notifier for MEM_OFFLINE events. 1423 * The error condition has been reported. Return 1424 * from here as if ignored. 1425 */ 1426 return NOTIFY_DONE; 1427 } 1428 } 1429 return NOTIFY_OK; 1430 } 1431 1432 static struct notifier_block prevent_bootmem_remove_nb = { 1433 .notifier_call = prevent_bootmem_remove_notifier, 1434 }; 1435 1436 /* 1437 * This ensures that boot memory sections on the platform are online 1438 * from early boot. Memory sections could not be prevented from being 1439 * offlined, unless for some reason they are not online to begin with. 1440 * This helps validate the basic assumption on which the above memory 1441 * event notifier works to prevent boot memory section offlining and 1442 * its possible removal. 1443 */ 1444 static void validate_bootmem_online(void) 1445 { 1446 phys_addr_t start, end, addr; 1447 struct mem_section *ms; 1448 u64 i; 1449 1450 /* 1451 * Scanning across all memblock might be expensive 1452 * on some big memory systems. Hence enable this 1453 * validation only with DEBUG_VM. 1454 */ 1455 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1456 return; 1457 1458 for_each_mem_range(i, &start, &end) { 1459 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1460 ms = __pfn_to_section(PHYS_PFN(addr)); 1461 1462 /* 1463 * All memory ranges in the system at this point 1464 * should have been marked as early sections. 1465 */ 1466 WARN_ON(!early_section(ms)); 1467 1468 /* 1469 * Memory notifier mechanism here to prevent boot 1470 * memory offlining depends on the fact that each 1471 * early section memory on the system is initially 1472 * online. Otherwise a given memory section which 1473 * is already offline will be overlooked and can 1474 * be removed completely. Call out such sections. 1475 */ 1476 if (!online_section(ms)) 1477 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1478 addr, addr + (1UL << PA_SECTION_SHIFT)); 1479 } 1480 } 1481 } 1482 1483 static int __init prevent_bootmem_remove_init(void) 1484 { 1485 int ret = 0; 1486 1487 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1488 return ret; 1489 1490 validate_bootmem_online(); 1491 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1492 if (ret) 1493 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1494 1495 return ret; 1496 } 1497 early_initcall(prevent_bootmem_remove_init); 1498 #endif 1499 1500 pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) 1501 { 1502 if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) { 1503 /* 1504 * Break-before-make (BBM) is required for all user space mappings 1505 * when the permission changes from executable to non-executable 1506 * in cases where cpu is affected with errata #2645198. 1507 */ 1508 if (pte_user_exec(ptep_get(ptep))) 1509 return ptep_clear_flush(vma, addr, ptep); 1510 } 1511 return ptep_get_and_clear(vma->vm_mm, addr, ptep); 1512 } 1513 1514 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, 1515 pte_t old_pte, pte_t pte) 1516 { 1517 set_pte_at(vma->vm_mm, addr, ptep, pte); 1518 } 1519 1520 /* 1521 * Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD, 1522 * avoiding the possibility of conflicting TLB entries being allocated. 1523 */ 1524 void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp) 1525 { 1526 typedef void (ttbr_replace_func)(phys_addr_t); 1527 extern ttbr_replace_func idmap_cpu_replace_ttbr1; 1528 ttbr_replace_func *replace_phys; 1529 unsigned long daif; 1530 1531 /* phys_to_ttbr() zeros lower 2 bits of ttbr with 52-bit PA */ 1532 phys_addr_t ttbr1 = phys_to_ttbr(virt_to_phys(pgdp)); 1533 1534 if (cnp) 1535 ttbr1 |= TTBR_CNP_BIT; 1536 1537 replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1); 1538 1539 cpu_install_idmap(); 1540 1541 /* 1542 * We really don't want to take *any* exceptions while TTBR1 is 1543 * in the process of being replaced so mask everything. 1544 */ 1545 daif = local_daif_save(); 1546 replace_phys(ttbr1); 1547 local_daif_restore(daif); 1548 1549 cpu_uninstall_idmap(); 1550 } 1551