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 #include <linux/pkeys.h> 29 30 #include <asm/barrier.h> 31 #include <asm/cputype.h> 32 #include <asm/fixmap.h> 33 #include <asm/kasan.h> 34 #include <asm/kernel-pgtable.h> 35 #include <asm/sections.h> 36 #include <asm/setup.h> 37 #include <linux/sizes.h> 38 #include <asm/tlb.h> 39 #include <asm/mmu_context.h> 40 #include <asm/ptdump.h> 41 #include <asm/tlbflush.h> 42 #include <asm/pgalloc.h> 43 #include <asm/kfence.h> 44 45 #define NO_BLOCK_MAPPINGS BIT(0) 46 #define NO_CONT_MAPPINGS BIT(1) 47 #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ 48 49 u64 kimage_voffset __ro_after_init; 50 EXPORT_SYMBOL(kimage_voffset); 51 52 u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 }; 53 54 static bool rodata_is_rw __ro_after_init = true; 55 56 /* 57 * The booting CPU updates the failed status @__early_cpu_boot_status, 58 * with MMU turned off. 59 */ 60 long __section(".mmuoff.data.write") __early_cpu_boot_status; 61 62 /* 63 * Empty_zero_page is a special page that is used for zero-initialized data 64 * and COW. 65 */ 66 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 67 EXPORT_SYMBOL(empty_zero_page); 68 69 static DEFINE_SPINLOCK(swapper_pgdir_lock); 70 static DEFINE_MUTEX(fixmap_lock); 71 72 void noinstr set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 73 { 74 pgd_t *fixmap_pgdp; 75 76 /* 77 * Don't bother with the fixmap if swapper_pg_dir is still mapped 78 * writable in the kernel mapping. 79 */ 80 if (rodata_is_rw) { 81 WRITE_ONCE(*pgdp, pgd); 82 dsb(ishst); 83 isb(); 84 return; 85 } 86 87 spin_lock(&swapper_pgdir_lock); 88 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 89 WRITE_ONCE(*fixmap_pgdp, pgd); 90 /* 91 * We need dsb(ishst) here to ensure the page-table-walker sees 92 * our new entry before set_p?d() returns. The fixmap's 93 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 94 */ 95 pgd_clear_fixmap(); 96 spin_unlock(&swapper_pgdir_lock); 97 } 98 99 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 100 unsigned long size, pgprot_t vma_prot) 101 { 102 if (!pfn_is_map_memory(pfn)) 103 return pgprot_noncached(vma_prot); 104 else if (file->f_flags & O_SYNC) 105 return pgprot_writecombine(vma_prot); 106 return vma_prot; 107 } 108 EXPORT_SYMBOL(phys_mem_access_prot); 109 110 static phys_addr_t __init early_pgtable_alloc(int shift) 111 { 112 phys_addr_t phys; 113 114 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 115 MEMBLOCK_ALLOC_NOLEAKTRACE); 116 if (!phys) 117 panic("Failed to allocate page table page\n"); 118 119 return phys; 120 } 121 122 bool pgattr_change_is_safe(pteval_t old, pteval_t new) 123 { 124 /* 125 * The following mapping attributes may be updated in live 126 * kernel mappings without the need for break-before-make. 127 */ 128 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG | 129 PTE_SWBITS_MASK; 130 131 /* creating or taking down mappings is always safe */ 132 if (!pte_valid(__pte(old)) || !pte_valid(__pte(new))) 133 return true; 134 135 /* A live entry's pfn should not change */ 136 if (pte_pfn(__pte(old)) != pte_pfn(__pte(new))) 137 return false; 138 139 /* live contiguous mappings may not be manipulated at all */ 140 if ((old | new) & PTE_CONT) 141 return false; 142 143 /* Transitioning from Non-Global to Global is unsafe */ 144 if (old & ~new & PTE_NG) 145 return false; 146 147 /* 148 * Changing the memory type between Normal and Normal-Tagged is safe 149 * since Tagged is considered a permission attribute from the 150 * mismatched attribute aliases perspective. 151 */ 152 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 153 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 154 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 155 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 156 mask |= PTE_ATTRINDX_MASK; 157 158 return ((old ^ new) & ~mask) == 0; 159 } 160 161 static void init_clear_pgtable(void *table) 162 { 163 clear_page(table); 164 165 /* Ensure the zeroing is observed by page table walks. */ 166 dsb(ishst); 167 } 168 169 static void init_pte(pte_t *ptep, unsigned long addr, unsigned long end, 170 phys_addr_t phys, pgprot_t prot) 171 { 172 do { 173 pte_t old_pte = __ptep_get(ptep); 174 175 /* 176 * Required barriers to make this visible to the table walker 177 * are deferred to the end of alloc_init_cont_pte(). 178 */ 179 __set_pte_nosync(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 pte_val(__ptep_get(ptep)))); 187 188 phys += PAGE_SIZE; 189 } while (ptep++, addr += PAGE_SIZE, addr != end); 190 } 191 192 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 193 unsigned long end, phys_addr_t phys, 194 pgprot_t prot, 195 phys_addr_t (*pgtable_alloc)(int), 196 int flags) 197 { 198 unsigned long next; 199 pmd_t pmd = READ_ONCE(*pmdp); 200 pte_t *ptep; 201 202 BUG_ON(pmd_sect(pmd)); 203 if (pmd_none(pmd)) { 204 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN | PMD_TABLE_AF; 205 phys_addr_t pte_phys; 206 207 if (flags & NO_EXEC_MAPPINGS) 208 pmdval |= PMD_TABLE_PXN; 209 BUG_ON(!pgtable_alloc); 210 pte_phys = pgtable_alloc(PAGE_SHIFT); 211 ptep = pte_set_fixmap(pte_phys); 212 init_clear_pgtable(ptep); 213 ptep += pte_index(addr); 214 __pmd_populate(pmdp, pte_phys, pmdval); 215 } else { 216 BUG_ON(pmd_bad(pmd)); 217 ptep = pte_set_fixmap_offset(pmdp, addr); 218 } 219 220 do { 221 pgprot_t __prot = prot; 222 223 next = pte_cont_addr_end(addr, end); 224 225 /* use a contiguous mapping if the range is suitably aligned */ 226 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 227 (flags & NO_CONT_MAPPINGS) == 0) 228 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 229 230 init_pte(ptep, addr, next, phys, __prot); 231 232 ptep += pte_index(next) - pte_index(addr); 233 phys += next - addr; 234 } while (addr = next, addr != end); 235 236 /* 237 * Note: barriers and maintenance necessary to clear the fixmap slot 238 * ensure that all previous pgtable writes are visible to the table 239 * walker. 240 */ 241 pte_clear_fixmap(); 242 } 243 244 static void init_pmd(pmd_t *pmdp, unsigned long addr, unsigned long end, 245 phys_addr_t phys, pgprot_t prot, 246 phys_addr_t (*pgtable_alloc)(int), int flags) 247 { 248 unsigned long next; 249 250 do { 251 pmd_t old_pmd = READ_ONCE(*pmdp); 252 253 next = pmd_addr_end(addr, end); 254 255 /* try section mapping first */ 256 if (((addr | next | phys) & ~PMD_MASK) == 0 && 257 (flags & NO_BLOCK_MAPPINGS) == 0) { 258 pmd_set_huge(pmdp, phys, prot); 259 260 /* 261 * After the PMD entry has been populated once, we 262 * only allow updates to the permission attributes. 263 */ 264 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 265 READ_ONCE(pmd_val(*pmdp)))); 266 } else { 267 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 268 pgtable_alloc, flags); 269 270 BUG_ON(pmd_val(old_pmd) != 0 && 271 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 272 } 273 phys += next - addr; 274 } while (pmdp++, addr = next, addr != end); 275 } 276 277 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 278 unsigned long end, phys_addr_t phys, 279 pgprot_t prot, 280 phys_addr_t (*pgtable_alloc)(int), int flags) 281 { 282 unsigned long next; 283 pud_t pud = READ_ONCE(*pudp); 284 pmd_t *pmdp; 285 286 /* 287 * Check for initial section mappings in the pgd/pud. 288 */ 289 BUG_ON(pud_sect(pud)); 290 if (pud_none(pud)) { 291 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN | PUD_TABLE_AF; 292 phys_addr_t pmd_phys; 293 294 if (flags & NO_EXEC_MAPPINGS) 295 pudval |= PUD_TABLE_PXN; 296 BUG_ON(!pgtable_alloc); 297 pmd_phys = pgtable_alloc(PMD_SHIFT); 298 pmdp = pmd_set_fixmap(pmd_phys); 299 init_clear_pgtable(pmdp); 300 pmdp += pmd_index(addr); 301 __pud_populate(pudp, pmd_phys, pudval); 302 } else { 303 BUG_ON(pud_bad(pud)); 304 pmdp = pmd_set_fixmap_offset(pudp, addr); 305 } 306 307 do { 308 pgprot_t __prot = prot; 309 310 next = pmd_cont_addr_end(addr, end); 311 312 /* use a contiguous mapping if the range is suitably aligned */ 313 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 314 (flags & NO_CONT_MAPPINGS) == 0) 315 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 316 317 init_pmd(pmdp, addr, next, phys, __prot, pgtable_alloc, flags); 318 319 pmdp += pmd_index(next) - pmd_index(addr); 320 phys += next - addr; 321 } while (addr = next, addr != end); 322 323 pmd_clear_fixmap(); 324 } 325 326 static void alloc_init_pud(p4d_t *p4dp, unsigned long addr, unsigned long end, 327 phys_addr_t phys, pgprot_t prot, 328 phys_addr_t (*pgtable_alloc)(int), 329 int flags) 330 { 331 unsigned long next; 332 p4d_t p4d = READ_ONCE(*p4dp); 333 pud_t *pudp; 334 335 if (p4d_none(p4d)) { 336 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN | P4D_TABLE_AF; 337 phys_addr_t pud_phys; 338 339 if (flags & NO_EXEC_MAPPINGS) 340 p4dval |= P4D_TABLE_PXN; 341 BUG_ON(!pgtable_alloc); 342 pud_phys = pgtable_alloc(PUD_SHIFT); 343 pudp = pud_set_fixmap(pud_phys); 344 init_clear_pgtable(pudp); 345 pudp += pud_index(addr); 346 __p4d_populate(p4dp, pud_phys, p4dval); 347 } else { 348 BUG_ON(p4d_bad(p4d)); 349 pudp = pud_set_fixmap_offset(p4dp, addr); 350 } 351 352 do { 353 pud_t old_pud = READ_ONCE(*pudp); 354 355 next = pud_addr_end(addr, end); 356 357 /* 358 * For 4K granule only, attempt to put down a 1GB block 359 */ 360 if (pud_sect_supported() && 361 ((addr | next | phys) & ~PUD_MASK) == 0 && 362 (flags & NO_BLOCK_MAPPINGS) == 0) { 363 pud_set_huge(pudp, phys, prot); 364 365 /* 366 * After the PUD entry has been populated once, we 367 * only allow updates to the permission attributes. 368 */ 369 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 370 READ_ONCE(pud_val(*pudp)))); 371 } else { 372 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 373 pgtable_alloc, flags); 374 375 BUG_ON(pud_val(old_pud) != 0 && 376 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 377 } 378 phys += next - addr; 379 } while (pudp++, addr = next, addr != end); 380 381 pud_clear_fixmap(); 382 } 383 384 static void alloc_init_p4d(pgd_t *pgdp, unsigned long addr, unsigned long end, 385 phys_addr_t phys, pgprot_t prot, 386 phys_addr_t (*pgtable_alloc)(int), 387 int flags) 388 { 389 unsigned long next; 390 pgd_t pgd = READ_ONCE(*pgdp); 391 p4d_t *p4dp; 392 393 if (pgd_none(pgd)) { 394 pgdval_t pgdval = PGD_TYPE_TABLE | PGD_TABLE_UXN | PGD_TABLE_AF; 395 phys_addr_t p4d_phys; 396 397 if (flags & NO_EXEC_MAPPINGS) 398 pgdval |= PGD_TABLE_PXN; 399 BUG_ON(!pgtable_alloc); 400 p4d_phys = pgtable_alloc(P4D_SHIFT); 401 p4dp = p4d_set_fixmap(p4d_phys); 402 init_clear_pgtable(p4dp); 403 p4dp += p4d_index(addr); 404 __pgd_populate(pgdp, p4d_phys, pgdval); 405 } else { 406 BUG_ON(pgd_bad(pgd)); 407 p4dp = p4d_set_fixmap_offset(pgdp, addr); 408 } 409 410 do { 411 p4d_t old_p4d = READ_ONCE(*p4dp); 412 413 next = p4d_addr_end(addr, end); 414 415 alloc_init_pud(p4dp, addr, next, phys, prot, 416 pgtable_alloc, flags); 417 418 BUG_ON(p4d_val(old_p4d) != 0 && 419 p4d_val(old_p4d) != READ_ONCE(p4d_val(*p4dp))); 420 421 phys += next - addr; 422 } while (p4dp++, addr = next, addr != end); 423 424 p4d_clear_fixmap(); 425 } 426 427 static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, 428 unsigned long virt, phys_addr_t size, 429 pgprot_t prot, 430 phys_addr_t (*pgtable_alloc)(int), 431 int flags) 432 { 433 unsigned long addr, end, next; 434 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 435 436 /* 437 * If the virtual and physical address don't have the same offset 438 * within a page, we cannot map the region as the caller expects. 439 */ 440 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 441 return; 442 443 phys &= PAGE_MASK; 444 addr = virt & PAGE_MASK; 445 end = PAGE_ALIGN(virt + size); 446 447 do { 448 next = pgd_addr_end(addr, end); 449 alloc_init_p4d(pgdp, addr, next, phys, prot, pgtable_alloc, 450 flags); 451 phys += next - addr; 452 } while (pgdp++, addr = next, addr != end); 453 } 454 455 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 456 unsigned long virt, phys_addr_t size, 457 pgprot_t prot, 458 phys_addr_t (*pgtable_alloc)(int), 459 int flags) 460 { 461 mutex_lock(&fixmap_lock); 462 __create_pgd_mapping_locked(pgdir, phys, virt, size, prot, 463 pgtable_alloc, flags); 464 mutex_unlock(&fixmap_lock); 465 } 466 467 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 468 extern __alias(__create_pgd_mapping_locked) 469 void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, 470 phys_addr_t size, pgprot_t prot, 471 phys_addr_t (*pgtable_alloc)(int), int flags); 472 #endif 473 474 static phys_addr_t __pgd_pgtable_alloc(int shift) 475 { 476 /* Page is zeroed by init_clear_pgtable() so don't duplicate effort. */ 477 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL & ~__GFP_ZERO); 478 479 BUG_ON(!ptr); 480 return __pa(ptr); 481 } 482 483 static phys_addr_t pgd_pgtable_alloc(int shift) 484 { 485 phys_addr_t pa = __pgd_pgtable_alloc(shift); 486 struct ptdesc *ptdesc = page_ptdesc(phys_to_page(pa)); 487 488 /* 489 * Call proper page table ctor in case later we need to 490 * call core mm functions like apply_to_page_range() on 491 * this pre-allocated page table. 492 * 493 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 494 * folded, and if so pagetable_pte_ctor() becomes nop. 495 */ 496 if (shift == PAGE_SHIFT) 497 BUG_ON(!pagetable_pte_ctor(ptdesc)); 498 else if (shift == PMD_SHIFT) 499 BUG_ON(!pagetable_pmd_ctor(ptdesc)); 500 501 return pa; 502 } 503 504 /* 505 * This function can only be used to modify existing table entries, 506 * without allocating new levels of table. Note that this permits the 507 * creation of new section or page entries. 508 */ 509 void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 510 phys_addr_t size, pgprot_t prot) 511 { 512 if (virt < PAGE_OFFSET) { 513 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 514 &phys, virt); 515 return; 516 } 517 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 518 NO_CONT_MAPPINGS); 519 } 520 521 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 522 unsigned long virt, phys_addr_t size, 523 pgprot_t prot, bool page_mappings_only) 524 { 525 int flags = 0; 526 527 BUG_ON(mm == &init_mm); 528 529 if (page_mappings_only) 530 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 531 532 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 533 pgd_pgtable_alloc, flags); 534 } 535 536 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 537 phys_addr_t size, pgprot_t prot) 538 { 539 if (virt < PAGE_OFFSET) { 540 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 541 &phys, virt); 542 return; 543 } 544 545 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 546 NO_CONT_MAPPINGS); 547 548 /* flush the TLBs after updating live kernel mappings */ 549 flush_tlb_kernel_range(virt, virt + size); 550 } 551 552 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 553 phys_addr_t end, pgprot_t prot, int flags) 554 { 555 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 556 prot, early_pgtable_alloc, flags); 557 } 558 559 void __init mark_linear_text_alias_ro(void) 560 { 561 /* 562 * Remove the write permissions from the linear alias of .text/.rodata 563 */ 564 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext), 565 (unsigned long)__init_begin - (unsigned long)_stext, 566 PAGE_KERNEL_RO); 567 } 568 569 #ifdef CONFIG_KFENCE 570 571 bool __ro_after_init kfence_early_init = !!CONFIG_KFENCE_SAMPLE_INTERVAL; 572 573 /* early_param() will be parsed before map_mem() below. */ 574 static int __init parse_kfence_early_init(char *arg) 575 { 576 int val; 577 578 if (get_option(&arg, &val)) 579 kfence_early_init = !!val; 580 return 0; 581 } 582 early_param("kfence.sample_interval", parse_kfence_early_init); 583 584 static phys_addr_t __init arm64_kfence_alloc_pool(void) 585 { 586 phys_addr_t kfence_pool; 587 588 if (!kfence_early_init) 589 return 0; 590 591 kfence_pool = memblock_phys_alloc(KFENCE_POOL_SIZE, PAGE_SIZE); 592 if (!kfence_pool) { 593 pr_err("failed to allocate kfence pool\n"); 594 kfence_early_init = false; 595 return 0; 596 } 597 598 /* Temporarily mark as NOMAP. */ 599 memblock_mark_nomap(kfence_pool, KFENCE_POOL_SIZE); 600 601 return kfence_pool; 602 } 603 604 static void __init arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) 605 { 606 if (!kfence_pool) 607 return; 608 609 /* KFENCE pool needs page-level mapping. */ 610 __map_memblock(pgdp, kfence_pool, kfence_pool + KFENCE_POOL_SIZE, 611 pgprot_tagged(PAGE_KERNEL), 612 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 613 memblock_clear_nomap(kfence_pool, KFENCE_POOL_SIZE); 614 __kfence_pool = phys_to_virt(kfence_pool); 615 } 616 #else /* CONFIG_KFENCE */ 617 618 static inline phys_addr_t arm64_kfence_alloc_pool(void) { return 0; } 619 static inline void arm64_kfence_map_pool(phys_addr_t kfence_pool, pgd_t *pgdp) { } 620 621 #endif /* CONFIG_KFENCE */ 622 623 static void __init map_mem(pgd_t *pgdp) 624 { 625 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 626 phys_addr_t kernel_start = __pa_symbol(_stext); 627 phys_addr_t kernel_end = __pa_symbol(__init_begin); 628 phys_addr_t start, end; 629 phys_addr_t early_kfence_pool; 630 int flags = NO_EXEC_MAPPINGS; 631 u64 i; 632 633 /* 634 * Setting hierarchical PXNTable attributes on table entries covering 635 * the linear region is only possible if it is guaranteed that no table 636 * entries at any level are being shared between the linear region and 637 * the vmalloc region. Check whether this is true for the PGD level, in 638 * which case it is guaranteed to be true for all other levels as well. 639 * (Unless we are running with support for LPA2, in which case the 640 * entire reduced VA space is covered by a single pgd_t which will have 641 * been populated without the PXNTable attribute by the time we get here.) 642 */ 643 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end) && 644 pgd_index(_PAGE_OFFSET(VA_BITS_MIN)) != PTRS_PER_PGD - 1); 645 646 early_kfence_pool = arm64_kfence_alloc_pool(); 647 648 if (can_set_direct_map()) 649 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 650 651 /* 652 * Take care not to create a writable alias for the 653 * read-only text and rodata sections of the kernel image. 654 * So temporarily mark them as NOMAP to skip mappings in 655 * the following for-loop 656 */ 657 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 658 659 /* map all the memory banks */ 660 for_each_mem_range(i, &start, &end) { 661 if (start >= end) 662 break; 663 /* 664 * The linear map must allow allocation tags reading/writing 665 * if MTE is present. Otherwise, it has the same attributes as 666 * PAGE_KERNEL. 667 */ 668 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 669 flags); 670 } 671 672 /* 673 * Map the linear alias of the [_stext, __init_begin) interval 674 * as non-executable now, and remove the write permission in 675 * mark_linear_text_alias_ro() below (which will be called after 676 * alternative patching has completed). This makes the contents 677 * of the region accessible to subsystems such as hibernate, 678 * but protects it from inadvertent modification or execution. 679 * Note that contiguous mappings cannot be remapped in this way, 680 * so we should avoid them here. 681 */ 682 __map_memblock(pgdp, kernel_start, kernel_end, 683 PAGE_KERNEL, NO_CONT_MAPPINGS); 684 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 685 arm64_kfence_map_pool(early_kfence_pool, pgdp); 686 } 687 688 void mark_rodata_ro(void) 689 { 690 unsigned long section_size; 691 692 /* 693 * mark .rodata as read only. Use __init_begin rather than __end_rodata 694 * to cover NOTES and EXCEPTION_TABLE. 695 */ 696 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 697 WRITE_ONCE(rodata_is_rw, false); 698 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 699 section_size, PAGE_KERNEL_RO); 700 } 701 702 static void __init declare_vma(struct vm_struct *vma, 703 void *va_start, void *va_end, 704 unsigned long vm_flags) 705 { 706 phys_addr_t pa_start = __pa_symbol(va_start); 707 unsigned long size = va_end - va_start; 708 709 BUG_ON(!PAGE_ALIGNED(pa_start)); 710 BUG_ON(!PAGE_ALIGNED(size)); 711 712 if (!(vm_flags & VM_NO_GUARD)) 713 size += PAGE_SIZE; 714 715 vma->addr = va_start; 716 vma->phys_addr = pa_start; 717 vma->size = size; 718 vma->flags = VM_MAP | vm_flags; 719 vma->caller = __builtin_return_address(0); 720 721 vm_area_add_early(vma); 722 } 723 724 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 725 static pgprot_t kernel_exec_prot(void) 726 { 727 return rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 728 } 729 730 static int __init map_entry_trampoline(void) 731 { 732 int i; 733 734 if (!arm64_kernel_unmapped_at_el0()) 735 return 0; 736 737 pgprot_t prot = kernel_exec_prot(); 738 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 739 740 /* The trampoline is always mapped and can therefore be global */ 741 pgprot_val(prot) &= ~PTE_NG; 742 743 /* Map only the text into the trampoline page table */ 744 memset(tramp_pg_dir, 0, PGD_SIZE); 745 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 746 entry_tramp_text_size(), prot, 747 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 748 749 /* Map both the text and data into the kernel page table */ 750 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 751 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 752 pa_start + i * PAGE_SIZE, prot); 753 754 if (IS_ENABLED(CONFIG_RELOCATABLE)) 755 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 756 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 757 758 return 0; 759 } 760 core_initcall(map_entry_trampoline); 761 #endif 762 763 /* 764 * Declare the VMA areas for the kernel 765 */ 766 static void __init declare_kernel_vmas(void) 767 { 768 static struct vm_struct vmlinux_seg[KERNEL_SEGMENT_COUNT]; 769 770 declare_vma(&vmlinux_seg[0], _stext, _etext, VM_NO_GUARD); 771 declare_vma(&vmlinux_seg[1], __start_rodata, __inittext_begin, VM_NO_GUARD); 772 declare_vma(&vmlinux_seg[2], __inittext_begin, __inittext_end, VM_NO_GUARD); 773 declare_vma(&vmlinux_seg[3], __initdata_begin, __initdata_end, VM_NO_GUARD); 774 declare_vma(&vmlinux_seg[4], _data, _end, 0); 775 } 776 777 void __pi_map_range(u64 *pgd, u64 start, u64 end, u64 pa, pgprot_t prot, 778 int level, pte_t *tbl, bool may_use_cont, u64 va_offset); 779 780 static u8 idmap_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init, 781 kpti_ptes[IDMAP_LEVELS - 1][PAGE_SIZE] __aligned(PAGE_SIZE) __ro_after_init; 782 783 static void __init create_idmap(void) 784 { 785 u64 start = __pa_symbol(__idmap_text_start); 786 u64 end = __pa_symbol(__idmap_text_end); 787 u64 ptep = __pa_symbol(idmap_ptes); 788 789 __pi_map_range(&ptep, start, end, start, PAGE_KERNEL_ROX, 790 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false, 791 __phys_to_virt(ptep) - ptep); 792 793 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0) && !arm64_use_ng_mappings) { 794 extern u32 __idmap_kpti_flag; 795 u64 pa = __pa_symbol(&__idmap_kpti_flag); 796 797 /* 798 * The KPTI G-to-nG conversion code needs a read-write mapping 799 * of its synchronization flag in the ID map. 800 */ 801 ptep = __pa_symbol(kpti_ptes); 802 __pi_map_range(&ptep, pa, pa + sizeof(u32), pa, PAGE_KERNEL, 803 IDMAP_ROOT_LEVEL, (pte_t *)idmap_pg_dir, false, 804 __phys_to_virt(ptep) - ptep); 805 } 806 } 807 808 void __init paging_init(void) 809 { 810 map_mem(swapper_pg_dir); 811 812 memblock_allow_resize(); 813 814 create_idmap(); 815 declare_kernel_vmas(); 816 } 817 818 #ifdef CONFIG_MEMORY_HOTPLUG 819 static void free_hotplug_page_range(struct page *page, size_t size, 820 struct vmem_altmap *altmap) 821 { 822 if (altmap) { 823 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 824 } else { 825 WARN_ON(PageReserved(page)); 826 free_pages((unsigned long)page_address(page), get_order(size)); 827 } 828 } 829 830 static void free_hotplug_pgtable_page(struct page *page) 831 { 832 free_hotplug_page_range(page, PAGE_SIZE, NULL); 833 } 834 835 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 836 unsigned long floor, unsigned long ceiling, 837 unsigned long mask) 838 { 839 start &= mask; 840 if (start < floor) 841 return false; 842 843 if (ceiling) { 844 ceiling &= mask; 845 if (!ceiling) 846 return false; 847 } 848 849 if (end - 1 > ceiling - 1) 850 return false; 851 return true; 852 } 853 854 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 855 unsigned long end, bool free_mapped, 856 struct vmem_altmap *altmap) 857 { 858 pte_t *ptep, pte; 859 860 do { 861 ptep = pte_offset_kernel(pmdp, addr); 862 pte = __ptep_get(ptep); 863 if (pte_none(pte)) 864 continue; 865 866 WARN_ON(!pte_present(pte)); 867 __pte_clear(&init_mm, addr, ptep); 868 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 869 if (free_mapped) 870 free_hotplug_page_range(pte_page(pte), 871 PAGE_SIZE, altmap); 872 } while (addr += PAGE_SIZE, addr < end); 873 } 874 875 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 876 unsigned long end, bool free_mapped, 877 struct vmem_altmap *altmap) 878 { 879 unsigned long next; 880 pmd_t *pmdp, pmd; 881 882 do { 883 next = pmd_addr_end(addr, end); 884 pmdp = pmd_offset(pudp, addr); 885 pmd = READ_ONCE(*pmdp); 886 if (pmd_none(pmd)) 887 continue; 888 889 WARN_ON(!pmd_present(pmd)); 890 if (pmd_sect(pmd)) { 891 pmd_clear(pmdp); 892 893 /* 894 * One TLBI should be sufficient here as the PMD_SIZE 895 * range is mapped with a single block entry. 896 */ 897 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 898 if (free_mapped) 899 free_hotplug_page_range(pmd_page(pmd), 900 PMD_SIZE, altmap); 901 continue; 902 } 903 WARN_ON(!pmd_table(pmd)); 904 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 905 } while (addr = next, addr < end); 906 } 907 908 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 909 unsigned long end, bool free_mapped, 910 struct vmem_altmap *altmap) 911 { 912 unsigned long next; 913 pud_t *pudp, pud; 914 915 do { 916 next = pud_addr_end(addr, end); 917 pudp = pud_offset(p4dp, addr); 918 pud = READ_ONCE(*pudp); 919 if (pud_none(pud)) 920 continue; 921 922 WARN_ON(!pud_present(pud)); 923 if (pud_sect(pud)) { 924 pud_clear(pudp); 925 926 /* 927 * One TLBI should be sufficient here as the PUD_SIZE 928 * range is mapped with a single block entry. 929 */ 930 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 931 if (free_mapped) 932 free_hotplug_page_range(pud_page(pud), 933 PUD_SIZE, altmap); 934 continue; 935 } 936 WARN_ON(!pud_table(pud)); 937 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 938 } while (addr = next, addr < end); 939 } 940 941 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 942 unsigned long end, bool free_mapped, 943 struct vmem_altmap *altmap) 944 { 945 unsigned long next; 946 p4d_t *p4dp, p4d; 947 948 do { 949 next = p4d_addr_end(addr, end); 950 p4dp = p4d_offset(pgdp, addr); 951 p4d = READ_ONCE(*p4dp); 952 if (p4d_none(p4d)) 953 continue; 954 955 WARN_ON(!p4d_present(p4d)); 956 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 957 } while (addr = next, addr < end); 958 } 959 960 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 961 bool free_mapped, struct vmem_altmap *altmap) 962 { 963 unsigned long next; 964 pgd_t *pgdp, pgd; 965 966 /* 967 * altmap can only be used as vmemmap mapping backing memory. 968 * In case the backing memory itself is not being freed, then 969 * altmap is irrelevant. Warn about this inconsistency when 970 * encountered. 971 */ 972 WARN_ON(!free_mapped && altmap); 973 974 do { 975 next = pgd_addr_end(addr, end); 976 pgdp = pgd_offset_k(addr); 977 pgd = READ_ONCE(*pgdp); 978 if (pgd_none(pgd)) 979 continue; 980 981 WARN_ON(!pgd_present(pgd)); 982 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 983 } while (addr = next, addr < end); 984 } 985 986 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 987 unsigned long end, unsigned long floor, 988 unsigned long ceiling) 989 { 990 pte_t *ptep, pte; 991 unsigned long i, start = addr; 992 993 do { 994 ptep = pte_offset_kernel(pmdp, addr); 995 pte = __ptep_get(ptep); 996 997 /* 998 * This is just a sanity check here which verifies that 999 * pte clearing has been done by earlier unmap loops. 1000 */ 1001 WARN_ON(!pte_none(pte)); 1002 } while (addr += PAGE_SIZE, addr < end); 1003 1004 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1005 return; 1006 1007 /* 1008 * Check whether we can free the pte page if the rest of the 1009 * entries are empty. Overlap with other regions have been 1010 * handled by the floor/ceiling check. 1011 */ 1012 ptep = pte_offset_kernel(pmdp, 0UL); 1013 for (i = 0; i < PTRS_PER_PTE; i++) { 1014 if (!pte_none(__ptep_get(&ptep[i]))) 1015 return; 1016 } 1017 1018 pmd_clear(pmdp); 1019 __flush_tlb_kernel_pgtable(start); 1020 free_hotplug_pgtable_page(virt_to_page(ptep)); 1021 } 1022 1023 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1024 unsigned long end, unsigned long floor, 1025 unsigned long ceiling) 1026 { 1027 pmd_t *pmdp, pmd; 1028 unsigned long i, next, start = addr; 1029 1030 do { 1031 next = pmd_addr_end(addr, end); 1032 pmdp = pmd_offset(pudp, addr); 1033 pmd = READ_ONCE(*pmdp); 1034 if (pmd_none(pmd)) 1035 continue; 1036 1037 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1038 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1039 } while (addr = next, addr < end); 1040 1041 if (CONFIG_PGTABLE_LEVELS <= 2) 1042 return; 1043 1044 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1045 return; 1046 1047 /* 1048 * Check whether we can free the pmd page if the rest of the 1049 * entries are empty. Overlap with other regions have been 1050 * handled by the floor/ceiling check. 1051 */ 1052 pmdp = pmd_offset(pudp, 0UL); 1053 for (i = 0; i < PTRS_PER_PMD; i++) { 1054 if (!pmd_none(READ_ONCE(pmdp[i]))) 1055 return; 1056 } 1057 1058 pud_clear(pudp); 1059 __flush_tlb_kernel_pgtable(start); 1060 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1061 } 1062 1063 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1064 unsigned long end, unsigned long floor, 1065 unsigned long ceiling) 1066 { 1067 pud_t *pudp, pud; 1068 unsigned long i, next, start = addr; 1069 1070 do { 1071 next = pud_addr_end(addr, end); 1072 pudp = pud_offset(p4dp, addr); 1073 pud = READ_ONCE(*pudp); 1074 if (pud_none(pud)) 1075 continue; 1076 1077 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1078 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1079 } while (addr = next, addr < end); 1080 1081 if (!pgtable_l4_enabled()) 1082 return; 1083 1084 if (!pgtable_range_aligned(start, end, floor, ceiling, P4D_MASK)) 1085 return; 1086 1087 /* 1088 * Check whether we can free the pud page if the rest of the 1089 * entries are empty. Overlap with other regions have been 1090 * handled by the floor/ceiling check. 1091 */ 1092 pudp = pud_offset(p4dp, 0UL); 1093 for (i = 0; i < PTRS_PER_PUD; i++) { 1094 if (!pud_none(READ_ONCE(pudp[i]))) 1095 return; 1096 } 1097 1098 p4d_clear(p4dp); 1099 __flush_tlb_kernel_pgtable(start); 1100 free_hotplug_pgtable_page(virt_to_page(pudp)); 1101 } 1102 1103 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1104 unsigned long end, unsigned long floor, 1105 unsigned long ceiling) 1106 { 1107 p4d_t *p4dp, p4d; 1108 unsigned long i, next, start = addr; 1109 1110 do { 1111 next = p4d_addr_end(addr, end); 1112 p4dp = p4d_offset(pgdp, addr); 1113 p4d = READ_ONCE(*p4dp); 1114 if (p4d_none(p4d)) 1115 continue; 1116 1117 WARN_ON(!p4d_present(p4d)); 1118 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1119 } while (addr = next, addr < end); 1120 1121 if (!pgtable_l5_enabled()) 1122 return; 1123 1124 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1125 return; 1126 1127 /* 1128 * Check whether we can free the p4d page if the rest of the 1129 * entries are empty. Overlap with other regions have been 1130 * handled by the floor/ceiling check. 1131 */ 1132 p4dp = p4d_offset(pgdp, 0UL); 1133 for (i = 0; i < PTRS_PER_P4D; i++) { 1134 if (!p4d_none(READ_ONCE(p4dp[i]))) 1135 return; 1136 } 1137 1138 pgd_clear(pgdp); 1139 __flush_tlb_kernel_pgtable(start); 1140 free_hotplug_pgtable_page(virt_to_page(p4dp)); 1141 } 1142 1143 static void free_empty_tables(unsigned long addr, unsigned long end, 1144 unsigned long floor, unsigned long ceiling) 1145 { 1146 unsigned long next; 1147 pgd_t *pgdp, pgd; 1148 1149 do { 1150 next = pgd_addr_end(addr, end); 1151 pgdp = pgd_offset_k(addr); 1152 pgd = READ_ONCE(*pgdp); 1153 if (pgd_none(pgd)) 1154 continue; 1155 1156 WARN_ON(!pgd_present(pgd)); 1157 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1158 } while (addr = next, addr < end); 1159 } 1160 #endif 1161 1162 void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node, 1163 unsigned long addr, unsigned long next) 1164 { 1165 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1166 } 1167 1168 int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node, 1169 unsigned long addr, unsigned long next) 1170 { 1171 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1172 1173 return pmd_sect(READ_ONCE(*pmdp)); 1174 } 1175 1176 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1177 struct vmem_altmap *altmap) 1178 { 1179 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1180 /* [start, end] should be within one section */ 1181 WARN_ON_ONCE(end - start > PAGES_PER_SECTION * sizeof(struct page)); 1182 1183 if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES) || 1184 (end - start < PAGES_PER_SECTION * sizeof(struct page))) 1185 return vmemmap_populate_basepages(start, end, node, altmap); 1186 else 1187 return vmemmap_populate_hugepages(start, end, node, altmap); 1188 } 1189 1190 #ifdef CONFIG_MEMORY_HOTPLUG 1191 void vmemmap_free(unsigned long start, unsigned long end, 1192 struct vmem_altmap *altmap) 1193 { 1194 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1195 1196 unmap_hotplug_range(start, end, true, altmap); 1197 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1198 } 1199 #endif /* CONFIG_MEMORY_HOTPLUG */ 1200 1201 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1202 { 1203 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1204 1205 /* Only allow permission changes for now */ 1206 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1207 pud_val(new_pud))) 1208 return 0; 1209 1210 VM_BUG_ON(phys & ~PUD_MASK); 1211 set_pud(pudp, new_pud); 1212 return 1; 1213 } 1214 1215 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1216 { 1217 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1218 1219 /* Only allow permission changes for now */ 1220 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1221 pmd_val(new_pmd))) 1222 return 0; 1223 1224 VM_BUG_ON(phys & ~PMD_MASK); 1225 set_pmd(pmdp, new_pmd); 1226 return 1; 1227 } 1228 1229 #ifndef __PAGETABLE_P4D_FOLDED 1230 void p4d_clear_huge(p4d_t *p4dp) 1231 { 1232 } 1233 #endif 1234 1235 int pud_clear_huge(pud_t *pudp) 1236 { 1237 if (!pud_sect(READ_ONCE(*pudp))) 1238 return 0; 1239 pud_clear(pudp); 1240 return 1; 1241 } 1242 1243 int pmd_clear_huge(pmd_t *pmdp) 1244 { 1245 if (!pmd_sect(READ_ONCE(*pmdp))) 1246 return 0; 1247 pmd_clear(pmdp); 1248 return 1; 1249 } 1250 1251 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1252 { 1253 pte_t *table; 1254 pmd_t pmd; 1255 1256 pmd = READ_ONCE(*pmdp); 1257 1258 if (!pmd_table(pmd)) { 1259 VM_WARN_ON(1); 1260 return 1; 1261 } 1262 1263 table = pte_offset_kernel(pmdp, addr); 1264 pmd_clear(pmdp); 1265 __flush_tlb_kernel_pgtable(addr); 1266 pte_free_kernel(NULL, table); 1267 return 1; 1268 } 1269 1270 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1271 { 1272 pmd_t *table; 1273 pmd_t *pmdp; 1274 pud_t pud; 1275 unsigned long next, end; 1276 1277 pud = READ_ONCE(*pudp); 1278 1279 if (!pud_table(pud)) { 1280 VM_WARN_ON(1); 1281 return 1; 1282 } 1283 1284 table = pmd_offset(pudp, addr); 1285 pmdp = table; 1286 next = addr; 1287 end = addr + PUD_SIZE; 1288 do { 1289 pmd_free_pte_page(pmdp, next); 1290 } while (pmdp++, next += PMD_SIZE, next != end); 1291 1292 pud_clear(pudp); 1293 __flush_tlb_kernel_pgtable(addr); 1294 pmd_free(NULL, table); 1295 return 1; 1296 } 1297 1298 #ifdef CONFIG_MEMORY_HOTPLUG 1299 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1300 { 1301 unsigned long end = start + size; 1302 1303 WARN_ON(pgdir != init_mm.pgd); 1304 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1305 1306 unmap_hotplug_range(start, end, false, NULL); 1307 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1308 } 1309 1310 struct range arch_get_mappable_range(void) 1311 { 1312 struct range mhp_range; 1313 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1314 u64 end_linear_pa = __pa(PAGE_END - 1); 1315 1316 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1317 /* 1318 * Check for a wrap, it is possible because of randomized linear 1319 * mapping the start physical address is actually bigger than 1320 * the end physical address. In this case set start to zero 1321 * because [0, end_linear_pa] range must still be able to cover 1322 * all addressable physical addresses. 1323 */ 1324 if (start_linear_pa > end_linear_pa) 1325 start_linear_pa = 0; 1326 } 1327 1328 WARN_ON(start_linear_pa > end_linear_pa); 1329 1330 /* 1331 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1332 * accommodating both its ends but excluding PAGE_END. Max physical 1333 * range which can be mapped inside this linear mapping range, must 1334 * also be derived from its end points. 1335 */ 1336 mhp_range.start = start_linear_pa; 1337 mhp_range.end = end_linear_pa; 1338 1339 return mhp_range; 1340 } 1341 1342 int arch_add_memory(int nid, u64 start, u64 size, 1343 struct mhp_params *params) 1344 { 1345 int ret, flags = NO_EXEC_MAPPINGS; 1346 1347 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1348 1349 if (can_set_direct_map()) 1350 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1351 1352 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1353 size, params->pgprot, __pgd_pgtable_alloc, 1354 flags); 1355 1356 memblock_clear_nomap(start, size); 1357 1358 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1359 params); 1360 if (ret) 1361 __remove_pgd_mapping(swapper_pg_dir, 1362 __phys_to_virt(start), size); 1363 else { 1364 /* Address of hotplugged memory can be smaller */ 1365 max_pfn = max(max_pfn, PFN_UP(start + size)); 1366 max_low_pfn = max_pfn; 1367 } 1368 1369 return ret; 1370 } 1371 1372 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1373 { 1374 unsigned long start_pfn = start >> PAGE_SHIFT; 1375 unsigned long nr_pages = size >> PAGE_SHIFT; 1376 1377 __remove_pages(start_pfn, nr_pages, altmap); 1378 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1379 } 1380 1381 /* 1382 * This memory hotplug notifier helps prevent boot memory from being 1383 * inadvertently removed as it blocks pfn range offlining process in 1384 * __offline_pages(). Hence this prevents both offlining as well as 1385 * removal process for boot memory which is initially always online. 1386 * In future if and when boot memory could be removed, this notifier 1387 * should be dropped and free_hotplug_page_range() should handle any 1388 * reserved pages allocated during boot. 1389 */ 1390 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1391 unsigned long action, void *data) 1392 { 1393 struct mem_section *ms; 1394 struct memory_notify *arg = data; 1395 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1396 unsigned long pfn = arg->start_pfn; 1397 1398 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1399 return NOTIFY_OK; 1400 1401 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1402 unsigned long start = PFN_PHYS(pfn); 1403 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1404 1405 ms = __pfn_to_section(pfn); 1406 if (!early_section(ms)) 1407 continue; 1408 1409 if (action == MEM_GOING_OFFLINE) { 1410 /* 1411 * Boot memory removal is not supported. Prevent 1412 * it via blocking any attempted offline request 1413 * for the boot memory and just report it. 1414 */ 1415 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1416 return NOTIFY_BAD; 1417 } else if (action == MEM_OFFLINE) { 1418 /* 1419 * This should have never happened. Boot memory 1420 * offlining should have been prevented by this 1421 * very notifier. Probably some memory removal 1422 * procedure might have changed which would then 1423 * require further debug. 1424 */ 1425 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1426 1427 /* 1428 * Core memory hotplug does not process a return 1429 * code from the notifier for MEM_OFFLINE events. 1430 * The error condition has been reported. Return 1431 * from here as if ignored. 1432 */ 1433 return NOTIFY_DONE; 1434 } 1435 } 1436 return NOTIFY_OK; 1437 } 1438 1439 static struct notifier_block prevent_bootmem_remove_nb = { 1440 .notifier_call = prevent_bootmem_remove_notifier, 1441 }; 1442 1443 /* 1444 * This ensures that boot memory sections on the platform are online 1445 * from early boot. Memory sections could not be prevented from being 1446 * offlined, unless for some reason they are not online to begin with. 1447 * This helps validate the basic assumption on which the above memory 1448 * event notifier works to prevent boot memory section offlining and 1449 * its possible removal. 1450 */ 1451 static void validate_bootmem_online(void) 1452 { 1453 phys_addr_t start, end, addr; 1454 struct mem_section *ms; 1455 u64 i; 1456 1457 /* 1458 * Scanning across all memblock might be expensive 1459 * on some big memory systems. Hence enable this 1460 * validation only with DEBUG_VM. 1461 */ 1462 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1463 return; 1464 1465 for_each_mem_range(i, &start, &end) { 1466 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1467 ms = __pfn_to_section(PHYS_PFN(addr)); 1468 1469 /* 1470 * All memory ranges in the system at this point 1471 * should have been marked as early sections. 1472 */ 1473 WARN_ON(!early_section(ms)); 1474 1475 /* 1476 * Memory notifier mechanism here to prevent boot 1477 * memory offlining depends on the fact that each 1478 * early section memory on the system is initially 1479 * online. Otherwise a given memory section which 1480 * is already offline will be overlooked and can 1481 * be removed completely. Call out such sections. 1482 */ 1483 if (!online_section(ms)) 1484 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1485 addr, addr + (1UL << PA_SECTION_SHIFT)); 1486 } 1487 } 1488 } 1489 1490 static int __init prevent_bootmem_remove_init(void) 1491 { 1492 int ret = 0; 1493 1494 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1495 return ret; 1496 1497 validate_bootmem_online(); 1498 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1499 if (ret) 1500 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1501 1502 return ret; 1503 } 1504 early_initcall(prevent_bootmem_remove_init); 1505 #endif 1506 1507 pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) 1508 { 1509 if (alternative_has_cap_unlikely(ARM64_WORKAROUND_2645198)) { 1510 /* 1511 * Break-before-make (BBM) is required for all user space mappings 1512 * when the permission changes from executable to non-executable 1513 * in cases where cpu is affected with errata #2645198. 1514 */ 1515 if (pte_user_exec(ptep_get(ptep))) 1516 return ptep_clear_flush(vma, addr, ptep); 1517 } 1518 return ptep_get_and_clear(vma->vm_mm, addr, ptep); 1519 } 1520 1521 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, 1522 pte_t old_pte, pte_t pte) 1523 { 1524 set_pte_at(vma->vm_mm, addr, ptep, pte); 1525 } 1526 1527 /* 1528 * Atomically replaces the active TTBR1_EL1 PGD with a new VA-compatible PGD, 1529 * avoiding the possibility of conflicting TLB entries being allocated. 1530 */ 1531 void __cpu_replace_ttbr1(pgd_t *pgdp, bool cnp) 1532 { 1533 typedef void (ttbr_replace_func)(phys_addr_t); 1534 extern ttbr_replace_func idmap_cpu_replace_ttbr1; 1535 ttbr_replace_func *replace_phys; 1536 unsigned long daif; 1537 1538 /* phys_to_ttbr() zeros lower 2 bits of ttbr with 52-bit PA */ 1539 phys_addr_t ttbr1 = phys_to_ttbr(virt_to_phys(pgdp)); 1540 1541 if (cnp) 1542 ttbr1 |= TTBR_CNP_BIT; 1543 1544 replace_phys = (void *)__pa_symbol(idmap_cpu_replace_ttbr1); 1545 1546 cpu_install_idmap(); 1547 1548 /* 1549 * We really don't want to take *any* exceptions while TTBR1 is 1550 * in the process of being replaced so mask everything. 1551 */ 1552 daif = local_daif_save(); 1553 replace_phys(ttbr1); 1554 local_daif_restore(daif); 1555 1556 cpu_uninstall_idmap(); 1557 } 1558 1559 #ifdef CONFIG_ARCH_HAS_PKEYS 1560 int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, unsigned long init_val) 1561 { 1562 u64 new_por; 1563 u64 old_por; 1564 1565 if (!system_supports_poe()) 1566 return -ENOSPC; 1567 1568 /* 1569 * This code should only be called with valid 'pkey' 1570 * values originating from in-kernel users. Complain 1571 * if a bad value is observed. 1572 */ 1573 if (WARN_ON_ONCE(pkey >= arch_max_pkey())) 1574 return -EINVAL; 1575 1576 /* Set the bits we need in POR: */ 1577 new_por = POE_RWX; 1578 if (init_val & PKEY_DISABLE_WRITE) 1579 new_por &= ~POE_W; 1580 if (init_val & PKEY_DISABLE_ACCESS) 1581 new_por &= ~POE_RW; 1582 if (init_val & PKEY_DISABLE_READ) 1583 new_por &= ~POE_R; 1584 if (init_val & PKEY_DISABLE_EXECUTE) 1585 new_por &= ~POE_X; 1586 1587 /* Shift the bits in to the correct place in POR for pkey: */ 1588 new_por = POR_ELx_PERM_PREP(pkey, new_por); 1589 1590 /* Get old POR and mask off any old bits in place: */ 1591 old_por = read_sysreg_s(SYS_POR_EL0); 1592 old_por &= ~(POE_MASK << POR_ELx_PERM_SHIFT(pkey)); 1593 1594 /* Write old part along with new part: */ 1595 write_sysreg_s(old_por | new_por, SYS_POR_EL0); 1596 1597 return 0; 1598 } 1599 #endif 1600