1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Based on arch/arm/mm/mmu.c 4 * 5 * Copyright (C) 1995-2005 Russell King 6 * Copyright (C) 2012 ARM Ltd. 7 */ 8 9 #include <linux/cache.h> 10 #include <linux/export.h> 11 #include <linux/kernel.h> 12 #include <linux/errno.h> 13 #include <linux/init.h> 14 #include <linux/ioport.h> 15 #include <linux/kexec.h> 16 #include <linux/libfdt.h> 17 #include <linux/mman.h> 18 #include <linux/nodemask.h> 19 #include <linux/memblock.h> 20 #include <linux/memremap.h> 21 #include <linux/memory.h> 22 #include <linux/fs.h> 23 #include <linux/io.h> 24 #include <linux/mm.h> 25 #include <linux/vmalloc.h> 26 #include <linux/set_memory.h> 27 28 #include <asm/barrier.h> 29 #include <asm/cputype.h> 30 #include <asm/fixmap.h> 31 #include <asm/kasan.h> 32 #include <asm/kernel-pgtable.h> 33 #include <asm/sections.h> 34 #include <asm/setup.h> 35 #include <linux/sizes.h> 36 #include <asm/tlb.h> 37 #include <asm/mmu_context.h> 38 #include <asm/ptdump.h> 39 #include <asm/tlbflush.h> 40 #include <asm/pgalloc.h> 41 42 #define NO_BLOCK_MAPPINGS BIT(0) 43 #define NO_CONT_MAPPINGS BIT(1) 44 #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ 45 46 u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN); 47 u64 idmap_ptrs_per_pgd = PTRS_PER_PGD; 48 49 u64 __section(".mmuoff.data.write") vabits_actual; 50 EXPORT_SYMBOL(vabits_actual); 51 52 u64 kimage_voffset __ro_after_init; 53 EXPORT_SYMBOL(kimage_voffset); 54 55 /* 56 * Empty_zero_page is a special page that is used for zero-initialized data 57 * and COW. 58 */ 59 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 60 EXPORT_SYMBOL(empty_zero_page); 61 62 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; 63 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; 64 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; 65 66 static DEFINE_SPINLOCK(swapper_pgdir_lock); 67 static DEFINE_MUTEX(fixmap_lock); 68 69 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 70 { 71 pgd_t *fixmap_pgdp; 72 73 spin_lock(&swapper_pgdir_lock); 74 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 75 WRITE_ONCE(*fixmap_pgdp, pgd); 76 /* 77 * We need dsb(ishst) here to ensure the page-table-walker sees 78 * our new entry before set_p?d() returns. The fixmap's 79 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 80 */ 81 pgd_clear_fixmap(); 82 spin_unlock(&swapper_pgdir_lock); 83 } 84 85 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 86 unsigned long size, pgprot_t vma_prot) 87 { 88 if (!pfn_is_map_memory(pfn)) 89 return pgprot_noncached(vma_prot); 90 else if (file->f_flags & O_SYNC) 91 return pgprot_writecombine(vma_prot); 92 return vma_prot; 93 } 94 EXPORT_SYMBOL(phys_mem_access_prot); 95 96 static phys_addr_t __init early_pgtable_alloc(int shift) 97 { 98 phys_addr_t phys; 99 void *ptr; 100 101 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 102 MEMBLOCK_ALLOC_NOLEAKTRACE); 103 if (!phys) 104 panic("Failed to allocate page table page\n"); 105 106 /* 107 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE 108 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise 109 * any level of table. 110 */ 111 ptr = pte_set_fixmap(phys); 112 113 memset(ptr, 0, PAGE_SIZE); 114 115 /* 116 * Implicit barriers also ensure the zeroed page is visible to the page 117 * table walker 118 */ 119 pte_clear_fixmap(); 120 121 return phys; 122 } 123 124 static bool pgattr_change_is_safe(u64 old, u64 new) 125 { 126 /* 127 * The following mapping attributes may be updated in live 128 * kernel mappings without the need for break-before-make. 129 */ 130 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 131 132 /* creating or taking down mappings is always safe */ 133 if (old == 0 || new == 0) 134 return true; 135 136 /* live contiguous mappings may not be manipulated at all */ 137 if ((old | new) & PTE_CONT) 138 return false; 139 140 /* Transitioning from Non-Global to Global is unsafe */ 141 if (old & ~new & PTE_NG) 142 return false; 143 144 /* 145 * Changing the memory type between Normal and Normal-Tagged is safe 146 * since Tagged is considered a permission attribute from the 147 * mismatched attribute aliases perspective. 148 */ 149 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 150 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 151 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 152 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 153 mask |= PTE_ATTRINDX_MASK; 154 155 return ((old ^ new) & ~mask) == 0; 156 } 157 158 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 159 phys_addr_t phys, pgprot_t prot) 160 { 161 pte_t *ptep; 162 163 ptep = pte_set_fixmap_offset(pmdp, addr); 164 do { 165 pte_t old_pte = READ_ONCE(*ptep); 166 167 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 168 169 /* 170 * After the PTE entry has been populated once, we 171 * only allow updates to the permission attributes. 172 */ 173 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 174 READ_ONCE(pte_val(*ptep)))); 175 176 phys += PAGE_SIZE; 177 } while (ptep++, addr += PAGE_SIZE, addr != end); 178 179 pte_clear_fixmap(); 180 } 181 182 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 183 unsigned long end, phys_addr_t phys, 184 pgprot_t prot, 185 phys_addr_t (*pgtable_alloc)(int), 186 int flags) 187 { 188 unsigned long next; 189 pmd_t pmd = READ_ONCE(*pmdp); 190 191 BUG_ON(pmd_sect(pmd)); 192 if (pmd_none(pmd)) { 193 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN; 194 phys_addr_t pte_phys; 195 196 if (flags & NO_EXEC_MAPPINGS) 197 pmdval |= PMD_TABLE_PXN; 198 BUG_ON(!pgtable_alloc); 199 pte_phys = pgtable_alloc(PAGE_SHIFT); 200 __pmd_populate(pmdp, pte_phys, pmdval); 201 pmd = READ_ONCE(*pmdp); 202 } 203 BUG_ON(pmd_bad(pmd)); 204 205 do { 206 pgprot_t __prot = prot; 207 208 next = pte_cont_addr_end(addr, end); 209 210 /* use a contiguous mapping if the range is suitably aligned */ 211 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 212 (flags & NO_CONT_MAPPINGS) == 0) 213 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 214 215 init_pte(pmdp, addr, next, phys, __prot); 216 217 phys += next - addr; 218 } while (addr = next, addr != end); 219 } 220 221 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 222 phys_addr_t phys, pgprot_t prot, 223 phys_addr_t (*pgtable_alloc)(int), int flags) 224 { 225 unsigned long next; 226 pmd_t *pmdp; 227 228 pmdp = pmd_set_fixmap_offset(pudp, addr); 229 do { 230 pmd_t old_pmd = READ_ONCE(*pmdp); 231 232 next = pmd_addr_end(addr, end); 233 234 /* try section mapping first */ 235 if (((addr | next | phys) & ~PMD_MASK) == 0 && 236 (flags & NO_BLOCK_MAPPINGS) == 0) { 237 pmd_set_huge(pmdp, phys, prot); 238 239 /* 240 * After the PMD entry has been populated once, we 241 * only allow updates to the permission attributes. 242 */ 243 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 244 READ_ONCE(pmd_val(*pmdp)))); 245 } else { 246 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 247 pgtable_alloc, flags); 248 249 BUG_ON(pmd_val(old_pmd) != 0 && 250 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 251 } 252 phys += next - addr; 253 } while (pmdp++, addr = next, addr != end); 254 255 pmd_clear_fixmap(); 256 } 257 258 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 259 unsigned long end, phys_addr_t phys, 260 pgprot_t prot, 261 phys_addr_t (*pgtable_alloc)(int), int flags) 262 { 263 unsigned long next; 264 pud_t pud = READ_ONCE(*pudp); 265 266 /* 267 * Check for initial section mappings in the pgd/pud. 268 */ 269 BUG_ON(pud_sect(pud)); 270 if (pud_none(pud)) { 271 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN; 272 phys_addr_t pmd_phys; 273 274 if (flags & NO_EXEC_MAPPINGS) 275 pudval |= PUD_TABLE_PXN; 276 BUG_ON(!pgtable_alloc); 277 pmd_phys = pgtable_alloc(PMD_SHIFT); 278 __pud_populate(pudp, pmd_phys, pudval); 279 pud = READ_ONCE(*pudp); 280 } 281 BUG_ON(pud_bad(pud)); 282 283 do { 284 pgprot_t __prot = prot; 285 286 next = pmd_cont_addr_end(addr, end); 287 288 /* use a contiguous mapping if the range is suitably aligned */ 289 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 290 (flags & NO_CONT_MAPPINGS) == 0) 291 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 292 293 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 294 295 phys += next - addr; 296 } while (addr = next, addr != end); 297 } 298 299 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 300 phys_addr_t phys, pgprot_t prot, 301 phys_addr_t (*pgtable_alloc)(int), 302 int flags) 303 { 304 unsigned long next; 305 pud_t *pudp; 306 p4d_t *p4dp = p4d_offset(pgdp, addr); 307 p4d_t p4d = READ_ONCE(*p4dp); 308 309 if (p4d_none(p4d)) { 310 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN; 311 phys_addr_t pud_phys; 312 313 if (flags & NO_EXEC_MAPPINGS) 314 p4dval |= P4D_TABLE_PXN; 315 BUG_ON(!pgtable_alloc); 316 pud_phys = pgtable_alloc(PUD_SHIFT); 317 __p4d_populate(p4dp, pud_phys, p4dval); 318 p4d = READ_ONCE(*p4dp); 319 } 320 BUG_ON(p4d_bad(p4d)); 321 322 /* 323 * No need for locking during early boot. And it doesn't work as 324 * expected with KASLR enabled. 325 */ 326 if (system_state != SYSTEM_BOOTING) 327 mutex_lock(&fixmap_lock); 328 pudp = pud_set_fixmap_offset(p4dp, addr); 329 do { 330 pud_t old_pud = READ_ONCE(*pudp); 331 332 next = pud_addr_end(addr, end); 333 334 /* 335 * For 4K granule only, attempt to put down a 1GB block 336 */ 337 if (pud_sect_supported() && 338 ((addr | next | phys) & ~PUD_MASK) == 0 && 339 (flags & NO_BLOCK_MAPPINGS) == 0) { 340 pud_set_huge(pudp, phys, prot); 341 342 /* 343 * After the PUD entry has been populated once, we 344 * only allow updates to the permission attributes. 345 */ 346 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 347 READ_ONCE(pud_val(*pudp)))); 348 } else { 349 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 350 pgtable_alloc, flags); 351 352 BUG_ON(pud_val(old_pud) != 0 && 353 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 354 } 355 phys += next - addr; 356 } while (pudp++, addr = next, addr != end); 357 358 pud_clear_fixmap(); 359 if (system_state != SYSTEM_BOOTING) 360 mutex_unlock(&fixmap_lock); 361 } 362 363 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 364 unsigned long virt, phys_addr_t size, 365 pgprot_t prot, 366 phys_addr_t (*pgtable_alloc)(int), 367 int flags) 368 { 369 unsigned long addr, end, next; 370 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 371 372 /* 373 * If the virtual and physical address don't have the same offset 374 * within a page, we cannot map the region as the caller expects. 375 */ 376 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 377 return; 378 379 phys &= PAGE_MASK; 380 addr = virt & PAGE_MASK; 381 end = PAGE_ALIGN(virt + size); 382 383 do { 384 next = pgd_addr_end(addr, end); 385 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 386 flags); 387 phys += next - addr; 388 } while (pgdp++, addr = next, addr != end); 389 } 390 391 static phys_addr_t __pgd_pgtable_alloc(int shift) 392 { 393 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 394 BUG_ON(!ptr); 395 396 /* Ensure the zeroed page is visible to the page table walker */ 397 dsb(ishst); 398 return __pa(ptr); 399 } 400 401 static phys_addr_t pgd_pgtable_alloc(int shift) 402 { 403 phys_addr_t pa = __pgd_pgtable_alloc(shift); 404 405 /* 406 * Call proper page table ctor in case later we need to 407 * call core mm functions like apply_to_page_range() on 408 * this pre-allocated page table. 409 * 410 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 411 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 412 */ 413 if (shift == PAGE_SHIFT) 414 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 415 else if (shift == PMD_SHIFT) 416 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 417 418 return pa; 419 } 420 421 /* 422 * This function can only be used to modify existing table entries, 423 * without allocating new levels of table. Note that this permits the 424 * creation of new section or page entries. 425 */ 426 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 427 phys_addr_t size, pgprot_t prot) 428 { 429 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 430 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 431 &phys, virt); 432 return; 433 } 434 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 435 NO_CONT_MAPPINGS); 436 } 437 438 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 439 unsigned long virt, phys_addr_t size, 440 pgprot_t prot, bool page_mappings_only) 441 { 442 int flags = 0; 443 444 BUG_ON(mm == &init_mm); 445 446 if (page_mappings_only) 447 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 448 449 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 450 pgd_pgtable_alloc, flags); 451 } 452 453 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 454 phys_addr_t size, pgprot_t prot) 455 { 456 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 457 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 458 &phys, virt); 459 return; 460 } 461 462 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 463 NO_CONT_MAPPINGS); 464 465 /* flush the TLBs after updating live kernel mappings */ 466 flush_tlb_kernel_range(virt, virt + size); 467 } 468 469 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 470 phys_addr_t end, pgprot_t prot, int flags) 471 { 472 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 473 prot, early_pgtable_alloc, flags); 474 } 475 476 void __init mark_linear_text_alias_ro(void) 477 { 478 /* 479 * Remove the write permissions from the linear alias of .text/.rodata 480 */ 481 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext), 482 (unsigned long)__init_begin - (unsigned long)_stext, 483 PAGE_KERNEL_RO); 484 } 485 486 static bool crash_mem_map __initdata; 487 488 static int __init enable_crash_mem_map(char *arg) 489 { 490 /* 491 * Proper parameter parsing is done by reserve_crashkernel(). We only 492 * need to know if the linear map has to avoid block mappings so that 493 * the crashkernel reservations can be unmapped later. 494 */ 495 crash_mem_map = true; 496 497 return 0; 498 } 499 early_param("crashkernel", enable_crash_mem_map); 500 501 static void __init map_mem(pgd_t *pgdp) 502 { 503 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 504 phys_addr_t kernel_start = __pa_symbol(_stext); 505 phys_addr_t kernel_end = __pa_symbol(__init_begin); 506 phys_addr_t start, end; 507 int flags = NO_EXEC_MAPPINGS; 508 u64 i; 509 510 /* 511 * Setting hierarchical PXNTable attributes on table entries covering 512 * the linear region is only possible if it is guaranteed that no table 513 * entries at any level are being shared between the linear region and 514 * the vmalloc region. Check whether this is true for the PGD level, in 515 * which case it is guaranteed to be true for all other levels as well. 516 */ 517 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); 518 519 if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) 520 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 521 522 /* 523 * Take care not to create a writable alias for the 524 * read-only text and rodata sections of the kernel image. 525 * So temporarily mark them as NOMAP to skip mappings in 526 * the following for-loop 527 */ 528 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 529 530 #ifdef CONFIG_KEXEC_CORE 531 if (crash_mem_map) { 532 if (IS_ENABLED(CONFIG_ZONE_DMA) || 533 IS_ENABLED(CONFIG_ZONE_DMA32)) 534 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 535 else if (crashk_res.end) 536 memblock_mark_nomap(crashk_res.start, 537 resource_size(&crashk_res)); 538 } 539 #endif 540 541 /* map all the memory banks */ 542 for_each_mem_range(i, &start, &end) { 543 if (start >= end) 544 break; 545 /* 546 * The linear map must allow allocation tags reading/writing 547 * if MTE is present. Otherwise, it has the same attributes as 548 * PAGE_KERNEL. 549 */ 550 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 551 flags); 552 } 553 554 /* 555 * Map the linear alias of the [_stext, __init_begin) interval 556 * as non-executable now, and remove the write permission in 557 * mark_linear_text_alias_ro() below (which will be called after 558 * alternative patching has completed). This makes the contents 559 * of the region accessible to subsystems such as hibernate, 560 * but protects it from inadvertent modification or execution. 561 * Note that contiguous mappings cannot be remapped in this way, 562 * so we should avoid them here. 563 */ 564 __map_memblock(pgdp, kernel_start, kernel_end, 565 PAGE_KERNEL, NO_CONT_MAPPINGS); 566 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 567 568 /* 569 * Use page-level mappings here so that we can shrink the region 570 * in page granularity and put back unused memory to buddy system 571 * through /sys/kernel/kexec_crash_size interface. 572 */ 573 #ifdef CONFIG_KEXEC_CORE 574 if (crash_mem_map && 575 !IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) { 576 if (crashk_res.end) { 577 __map_memblock(pgdp, crashk_res.start, 578 crashk_res.end + 1, 579 PAGE_KERNEL, 580 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 581 memblock_clear_nomap(crashk_res.start, 582 resource_size(&crashk_res)); 583 } 584 } 585 #endif 586 } 587 588 void mark_rodata_ro(void) 589 { 590 unsigned long section_size; 591 592 /* 593 * mark .rodata as read only. Use __init_begin rather than __end_rodata 594 * to cover NOTES and EXCEPTION_TABLE. 595 */ 596 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 597 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 598 section_size, PAGE_KERNEL_RO); 599 600 debug_checkwx(); 601 } 602 603 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 604 pgprot_t prot, struct vm_struct *vma, 605 int flags, unsigned long vm_flags) 606 { 607 phys_addr_t pa_start = __pa_symbol(va_start); 608 unsigned long size = va_end - va_start; 609 610 BUG_ON(!PAGE_ALIGNED(pa_start)); 611 BUG_ON(!PAGE_ALIGNED(size)); 612 613 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 614 early_pgtable_alloc, flags); 615 616 if (!(vm_flags & VM_NO_GUARD)) 617 size += PAGE_SIZE; 618 619 vma->addr = va_start; 620 vma->phys_addr = pa_start; 621 vma->size = size; 622 vma->flags = VM_MAP | vm_flags; 623 vma->caller = __builtin_return_address(0); 624 625 vm_area_add_early(vma); 626 } 627 628 static int __init parse_rodata(char *arg) 629 { 630 int ret = strtobool(arg, &rodata_enabled); 631 if (!ret) { 632 rodata_full = false; 633 return 0; 634 } 635 636 /* permit 'full' in addition to boolean options */ 637 if (strcmp(arg, "full")) 638 return -EINVAL; 639 640 rodata_enabled = true; 641 rodata_full = true; 642 return 0; 643 } 644 early_param("rodata", parse_rodata); 645 646 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 647 static int __init map_entry_trampoline(void) 648 { 649 int i; 650 651 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 652 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 653 654 /* The trampoline is always mapped and can therefore be global */ 655 pgprot_val(prot) &= ~PTE_NG; 656 657 /* Map only the text into the trampoline page table */ 658 memset(tramp_pg_dir, 0, PGD_SIZE); 659 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 660 entry_tramp_text_size(), prot, 661 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 662 663 /* Map both the text and data into the kernel page table */ 664 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 665 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 666 pa_start + i * PAGE_SIZE, prot); 667 668 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 669 extern char __entry_tramp_data_start[]; 670 671 __set_fixmap(FIX_ENTRY_TRAMP_DATA, 672 __pa_symbol(__entry_tramp_data_start), 673 PAGE_KERNEL_RO); 674 } 675 676 return 0; 677 } 678 core_initcall(map_entry_trampoline); 679 #endif 680 681 /* 682 * Open coded check for BTI, only for use to determine configuration 683 * for early mappings for before the cpufeature code has run. 684 */ 685 static bool arm64_early_this_cpu_has_bti(void) 686 { 687 u64 pfr1; 688 689 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 690 return false; 691 692 pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1); 693 return cpuid_feature_extract_unsigned_field(pfr1, 694 ID_AA64PFR1_BT_SHIFT); 695 } 696 697 /* 698 * Create fine-grained mappings for the kernel. 699 */ 700 static void __init map_kernel(pgd_t *pgdp) 701 { 702 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 703 vmlinux_initdata, vmlinux_data; 704 705 /* 706 * External debuggers may need to write directly to the text 707 * mapping to install SW breakpoints. Allow this (only) when 708 * explicitly requested with rodata=off. 709 */ 710 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 711 712 /* 713 * If we have a CPU that supports BTI and a kernel built for 714 * BTI then mark the kernel executable text as guarded pages 715 * now so we don't have to rewrite the page tables later. 716 */ 717 if (arm64_early_this_cpu_has_bti()) 718 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 719 720 /* 721 * Only rodata will be remapped with different permissions later on, 722 * all other segments are allowed to use contiguous mappings. 723 */ 724 map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0, 725 VM_NO_GUARD); 726 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 727 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 728 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 729 &vmlinux_inittext, 0, VM_NO_GUARD); 730 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 731 &vmlinux_initdata, 0, VM_NO_GUARD); 732 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 733 734 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { 735 /* 736 * The fixmap falls in a separate pgd to the kernel, and doesn't 737 * live in the carveout for the swapper_pg_dir. We can simply 738 * re-use the existing dir for the fixmap. 739 */ 740 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), 741 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 742 } else if (CONFIG_PGTABLE_LEVELS > 3) { 743 pgd_t *bm_pgdp; 744 p4d_t *bm_p4dp; 745 pud_t *bm_pudp; 746 /* 747 * The fixmap shares its top level pgd entry with the kernel 748 * mapping. This can really only occur when we are running 749 * with 16k/4 levels, so we can simply reuse the pud level 750 * entry instead. 751 */ 752 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 753 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); 754 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); 755 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); 756 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 757 pud_clear_fixmap(); 758 } else { 759 BUG(); 760 } 761 762 kasan_copy_shadow(pgdp); 763 } 764 765 void __init paging_init(void) 766 { 767 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 768 769 map_kernel(pgdp); 770 map_mem(pgdp); 771 772 pgd_clear_fixmap(); 773 774 cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); 775 init_mm.pgd = swapper_pg_dir; 776 777 memblock_phys_free(__pa_symbol(init_pg_dir), 778 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 779 780 memblock_allow_resize(); 781 } 782 783 /* 784 * Check whether a kernel address is valid (derived from arch/x86/). 785 */ 786 int kern_addr_valid(unsigned long addr) 787 { 788 pgd_t *pgdp; 789 p4d_t *p4dp; 790 pud_t *pudp, pud; 791 pmd_t *pmdp, pmd; 792 pte_t *ptep, pte; 793 794 addr = arch_kasan_reset_tag(addr); 795 if ((((long)addr) >> VA_BITS) != -1UL) 796 return 0; 797 798 pgdp = pgd_offset_k(addr); 799 if (pgd_none(READ_ONCE(*pgdp))) 800 return 0; 801 802 p4dp = p4d_offset(pgdp, addr); 803 if (p4d_none(READ_ONCE(*p4dp))) 804 return 0; 805 806 pudp = pud_offset(p4dp, addr); 807 pud = READ_ONCE(*pudp); 808 if (pud_none(pud)) 809 return 0; 810 811 if (pud_sect(pud)) 812 return pfn_valid(pud_pfn(pud)); 813 814 pmdp = pmd_offset(pudp, addr); 815 pmd = READ_ONCE(*pmdp); 816 if (pmd_none(pmd)) 817 return 0; 818 819 if (pmd_sect(pmd)) 820 return pfn_valid(pmd_pfn(pmd)); 821 822 ptep = pte_offset_kernel(pmdp, addr); 823 pte = READ_ONCE(*ptep); 824 if (pte_none(pte)) 825 return 0; 826 827 return pfn_valid(pte_pfn(pte)); 828 } 829 830 #ifdef CONFIG_MEMORY_HOTPLUG 831 static void free_hotplug_page_range(struct page *page, size_t size, 832 struct vmem_altmap *altmap) 833 { 834 if (altmap) { 835 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 836 } else { 837 WARN_ON(PageReserved(page)); 838 free_pages((unsigned long)page_address(page), get_order(size)); 839 } 840 } 841 842 static void free_hotplug_pgtable_page(struct page *page) 843 { 844 free_hotplug_page_range(page, PAGE_SIZE, NULL); 845 } 846 847 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 848 unsigned long floor, unsigned long ceiling, 849 unsigned long mask) 850 { 851 start &= mask; 852 if (start < floor) 853 return false; 854 855 if (ceiling) { 856 ceiling &= mask; 857 if (!ceiling) 858 return false; 859 } 860 861 if (end - 1 > ceiling - 1) 862 return false; 863 return true; 864 } 865 866 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 867 unsigned long end, bool free_mapped, 868 struct vmem_altmap *altmap) 869 { 870 pte_t *ptep, pte; 871 872 do { 873 ptep = pte_offset_kernel(pmdp, addr); 874 pte = READ_ONCE(*ptep); 875 if (pte_none(pte)) 876 continue; 877 878 WARN_ON(!pte_present(pte)); 879 pte_clear(&init_mm, addr, ptep); 880 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 881 if (free_mapped) 882 free_hotplug_page_range(pte_page(pte), 883 PAGE_SIZE, altmap); 884 } while (addr += PAGE_SIZE, addr < end); 885 } 886 887 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 888 unsigned long end, bool free_mapped, 889 struct vmem_altmap *altmap) 890 { 891 unsigned long next; 892 pmd_t *pmdp, pmd; 893 894 do { 895 next = pmd_addr_end(addr, end); 896 pmdp = pmd_offset(pudp, addr); 897 pmd = READ_ONCE(*pmdp); 898 if (pmd_none(pmd)) 899 continue; 900 901 WARN_ON(!pmd_present(pmd)); 902 if (pmd_sect(pmd)) { 903 pmd_clear(pmdp); 904 905 /* 906 * One TLBI should be sufficient here as the PMD_SIZE 907 * range is mapped with a single block entry. 908 */ 909 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 910 if (free_mapped) 911 free_hotplug_page_range(pmd_page(pmd), 912 PMD_SIZE, altmap); 913 continue; 914 } 915 WARN_ON(!pmd_table(pmd)); 916 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 917 } while (addr = next, addr < end); 918 } 919 920 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 921 unsigned long end, bool free_mapped, 922 struct vmem_altmap *altmap) 923 { 924 unsigned long next; 925 pud_t *pudp, pud; 926 927 do { 928 next = pud_addr_end(addr, end); 929 pudp = pud_offset(p4dp, addr); 930 pud = READ_ONCE(*pudp); 931 if (pud_none(pud)) 932 continue; 933 934 WARN_ON(!pud_present(pud)); 935 if (pud_sect(pud)) { 936 pud_clear(pudp); 937 938 /* 939 * One TLBI should be sufficient here as the PUD_SIZE 940 * range is mapped with a single block entry. 941 */ 942 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 943 if (free_mapped) 944 free_hotplug_page_range(pud_page(pud), 945 PUD_SIZE, altmap); 946 continue; 947 } 948 WARN_ON(!pud_table(pud)); 949 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 950 } while (addr = next, addr < end); 951 } 952 953 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 954 unsigned long end, bool free_mapped, 955 struct vmem_altmap *altmap) 956 { 957 unsigned long next; 958 p4d_t *p4dp, p4d; 959 960 do { 961 next = p4d_addr_end(addr, end); 962 p4dp = p4d_offset(pgdp, addr); 963 p4d = READ_ONCE(*p4dp); 964 if (p4d_none(p4d)) 965 continue; 966 967 WARN_ON(!p4d_present(p4d)); 968 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 969 } while (addr = next, addr < end); 970 } 971 972 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 973 bool free_mapped, struct vmem_altmap *altmap) 974 { 975 unsigned long next; 976 pgd_t *pgdp, pgd; 977 978 /* 979 * altmap can only be used as vmemmap mapping backing memory. 980 * In case the backing memory itself is not being freed, then 981 * altmap is irrelevant. Warn about this inconsistency when 982 * encountered. 983 */ 984 WARN_ON(!free_mapped && altmap); 985 986 do { 987 next = pgd_addr_end(addr, end); 988 pgdp = pgd_offset_k(addr); 989 pgd = READ_ONCE(*pgdp); 990 if (pgd_none(pgd)) 991 continue; 992 993 WARN_ON(!pgd_present(pgd)); 994 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 995 } while (addr = next, addr < end); 996 } 997 998 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 999 unsigned long end, unsigned long floor, 1000 unsigned long ceiling) 1001 { 1002 pte_t *ptep, pte; 1003 unsigned long i, start = addr; 1004 1005 do { 1006 ptep = pte_offset_kernel(pmdp, addr); 1007 pte = READ_ONCE(*ptep); 1008 1009 /* 1010 * This is just a sanity check here which verifies that 1011 * pte clearing has been done by earlier unmap loops. 1012 */ 1013 WARN_ON(!pte_none(pte)); 1014 } while (addr += PAGE_SIZE, addr < end); 1015 1016 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1017 return; 1018 1019 /* 1020 * Check whether we can free the pte page if the rest of the 1021 * entries are empty. Overlap with other regions have been 1022 * handled by the floor/ceiling check. 1023 */ 1024 ptep = pte_offset_kernel(pmdp, 0UL); 1025 for (i = 0; i < PTRS_PER_PTE; i++) { 1026 if (!pte_none(READ_ONCE(ptep[i]))) 1027 return; 1028 } 1029 1030 pmd_clear(pmdp); 1031 __flush_tlb_kernel_pgtable(start); 1032 free_hotplug_pgtable_page(virt_to_page(ptep)); 1033 } 1034 1035 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1036 unsigned long end, unsigned long floor, 1037 unsigned long ceiling) 1038 { 1039 pmd_t *pmdp, pmd; 1040 unsigned long i, next, start = addr; 1041 1042 do { 1043 next = pmd_addr_end(addr, end); 1044 pmdp = pmd_offset(pudp, addr); 1045 pmd = READ_ONCE(*pmdp); 1046 if (pmd_none(pmd)) 1047 continue; 1048 1049 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1050 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1051 } while (addr = next, addr < end); 1052 1053 if (CONFIG_PGTABLE_LEVELS <= 2) 1054 return; 1055 1056 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1057 return; 1058 1059 /* 1060 * Check whether we can free the pmd page if the rest of the 1061 * entries are empty. Overlap with other regions have been 1062 * handled by the floor/ceiling check. 1063 */ 1064 pmdp = pmd_offset(pudp, 0UL); 1065 for (i = 0; i < PTRS_PER_PMD; i++) { 1066 if (!pmd_none(READ_ONCE(pmdp[i]))) 1067 return; 1068 } 1069 1070 pud_clear(pudp); 1071 __flush_tlb_kernel_pgtable(start); 1072 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1073 } 1074 1075 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1076 unsigned long end, unsigned long floor, 1077 unsigned long ceiling) 1078 { 1079 pud_t *pudp, pud; 1080 unsigned long i, next, start = addr; 1081 1082 do { 1083 next = pud_addr_end(addr, end); 1084 pudp = pud_offset(p4dp, addr); 1085 pud = READ_ONCE(*pudp); 1086 if (pud_none(pud)) 1087 continue; 1088 1089 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1090 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1091 } while (addr = next, addr < end); 1092 1093 if (CONFIG_PGTABLE_LEVELS <= 3) 1094 return; 1095 1096 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1097 return; 1098 1099 /* 1100 * Check whether we can free the pud page if the rest of the 1101 * entries are empty. Overlap with other regions have been 1102 * handled by the floor/ceiling check. 1103 */ 1104 pudp = pud_offset(p4dp, 0UL); 1105 for (i = 0; i < PTRS_PER_PUD; i++) { 1106 if (!pud_none(READ_ONCE(pudp[i]))) 1107 return; 1108 } 1109 1110 p4d_clear(p4dp); 1111 __flush_tlb_kernel_pgtable(start); 1112 free_hotplug_pgtable_page(virt_to_page(pudp)); 1113 } 1114 1115 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1116 unsigned long end, unsigned long floor, 1117 unsigned long ceiling) 1118 { 1119 unsigned long next; 1120 p4d_t *p4dp, p4d; 1121 1122 do { 1123 next = p4d_addr_end(addr, end); 1124 p4dp = p4d_offset(pgdp, addr); 1125 p4d = READ_ONCE(*p4dp); 1126 if (p4d_none(p4d)) 1127 continue; 1128 1129 WARN_ON(!p4d_present(p4d)); 1130 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1131 } while (addr = next, addr < end); 1132 } 1133 1134 static void free_empty_tables(unsigned long addr, unsigned long end, 1135 unsigned long floor, unsigned long ceiling) 1136 { 1137 unsigned long next; 1138 pgd_t *pgdp, pgd; 1139 1140 do { 1141 next = pgd_addr_end(addr, end); 1142 pgdp = pgd_offset_k(addr); 1143 pgd = READ_ONCE(*pgdp); 1144 if (pgd_none(pgd)) 1145 continue; 1146 1147 WARN_ON(!pgd_present(pgd)); 1148 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1149 } while (addr = next, addr < end); 1150 } 1151 #endif 1152 1153 #if !ARM64_KERNEL_USES_PMD_MAPS 1154 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1155 struct vmem_altmap *altmap) 1156 { 1157 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1158 return vmemmap_populate_basepages(start, end, node, altmap); 1159 } 1160 #else /* !ARM64_KERNEL_USES_PMD_MAPS */ 1161 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1162 struct vmem_altmap *altmap) 1163 { 1164 unsigned long addr = start; 1165 unsigned long next; 1166 pgd_t *pgdp; 1167 p4d_t *p4dp; 1168 pud_t *pudp; 1169 pmd_t *pmdp; 1170 1171 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1172 do { 1173 next = pmd_addr_end(addr, end); 1174 1175 pgdp = vmemmap_pgd_populate(addr, node); 1176 if (!pgdp) 1177 return -ENOMEM; 1178 1179 p4dp = vmemmap_p4d_populate(pgdp, addr, node); 1180 if (!p4dp) 1181 return -ENOMEM; 1182 1183 pudp = vmemmap_pud_populate(p4dp, addr, node); 1184 if (!pudp) 1185 return -ENOMEM; 1186 1187 pmdp = pmd_offset(pudp, addr); 1188 if (pmd_none(READ_ONCE(*pmdp))) { 1189 void *p = NULL; 1190 1191 p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); 1192 if (!p) { 1193 if (vmemmap_populate_basepages(addr, next, node, altmap)) 1194 return -ENOMEM; 1195 continue; 1196 } 1197 1198 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1199 } else 1200 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1201 } while (addr = next, addr != end); 1202 1203 return 0; 1204 } 1205 #endif /* !ARM64_KERNEL_USES_PMD_MAPS */ 1206 1207 #ifdef CONFIG_MEMORY_HOTPLUG 1208 void vmemmap_free(unsigned long start, unsigned long end, 1209 struct vmem_altmap *altmap) 1210 { 1211 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1212 1213 unmap_hotplug_range(start, end, true, altmap); 1214 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1215 } 1216 #endif /* CONFIG_MEMORY_HOTPLUG */ 1217 1218 static inline pud_t *fixmap_pud(unsigned long addr) 1219 { 1220 pgd_t *pgdp = pgd_offset_k(addr); 1221 p4d_t *p4dp = p4d_offset(pgdp, addr); 1222 p4d_t p4d = READ_ONCE(*p4dp); 1223 1224 BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); 1225 1226 return pud_offset_kimg(p4dp, addr); 1227 } 1228 1229 static inline pmd_t *fixmap_pmd(unsigned long addr) 1230 { 1231 pud_t *pudp = fixmap_pud(addr); 1232 pud_t pud = READ_ONCE(*pudp); 1233 1234 BUG_ON(pud_none(pud) || pud_bad(pud)); 1235 1236 return pmd_offset_kimg(pudp, addr); 1237 } 1238 1239 static inline pte_t *fixmap_pte(unsigned long addr) 1240 { 1241 return &bm_pte[pte_index(addr)]; 1242 } 1243 1244 /* 1245 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 1246 * directly on kernel symbols (bm_p*d). This function is called too early to use 1247 * lm_alias so __p*d_populate functions must be used to populate with the 1248 * physical address from __pa_symbol. 1249 */ 1250 void __init early_fixmap_init(void) 1251 { 1252 pgd_t *pgdp; 1253 p4d_t *p4dp, p4d; 1254 pud_t *pudp; 1255 pmd_t *pmdp; 1256 unsigned long addr = FIXADDR_START; 1257 1258 pgdp = pgd_offset_k(addr); 1259 p4dp = p4d_offset(pgdp, addr); 1260 p4d = READ_ONCE(*p4dp); 1261 if (CONFIG_PGTABLE_LEVELS > 3 && 1262 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { 1263 /* 1264 * We only end up here if the kernel mapping and the fixmap 1265 * share the top level pgd entry, which should only happen on 1266 * 16k/4 levels configurations. 1267 */ 1268 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 1269 pudp = pud_offset_kimg(p4dp, addr); 1270 } else { 1271 if (p4d_none(p4d)) 1272 __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); 1273 pudp = fixmap_pud(addr); 1274 } 1275 if (pud_none(READ_ONCE(*pudp))) 1276 __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); 1277 pmdp = fixmap_pmd(addr); 1278 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 1279 1280 /* 1281 * The boot-ioremap range spans multiple pmds, for which 1282 * we are not prepared: 1283 */ 1284 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 1285 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 1286 1287 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 1288 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 1289 WARN_ON(1); 1290 pr_warn("pmdp %p != %p, %p\n", 1291 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 1292 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 1293 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 1294 fix_to_virt(FIX_BTMAP_BEGIN)); 1295 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 1296 fix_to_virt(FIX_BTMAP_END)); 1297 1298 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 1299 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 1300 } 1301 } 1302 1303 /* 1304 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 1305 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 1306 */ 1307 void __set_fixmap(enum fixed_addresses idx, 1308 phys_addr_t phys, pgprot_t flags) 1309 { 1310 unsigned long addr = __fix_to_virt(idx); 1311 pte_t *ptep; 1312 1313 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 1314 1315 ptep = fixmap_pte(addr); 1316 1317 if (pgprot_val(flags)) { 1318 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 1319 } else { 1320 pte_clear(&init_mm, addr, ptep); 1321 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 1322 } 1323 } 1324 1325 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 1326 { 1327 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 1328 int offset; 1329 void *dt_virt; 1330 1331 /* 1332 * Check whether the physical FDT address is set and meets the minimum 1333 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 1334 * at least 8 bytes so that we can always access the magic and size 1335 * fields of the FDT header after mapping the first chunk, double check 1336 * here if that is indeed the case. 1337 */ 1338 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 1339 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 1340 return NULL; 1341 1342 /* 1343 * Make sure that the FDT region can be mapped without the need to 1344 * allocate additional translation table pages, so that it is safe 1345 * to call create_mapping_noalloc() this early. 1346 * 1347 * On 64k pages, the FDT will be mapped using PTEs, so we need to 1348 * be in the same PMD as the rest of the fixmap. 1349 * On 4k pages, we'll use section mappings for the FDT so we only 1350 * have to be in the same PUD. 1351 */ 1352 BUILD_BUG_ON(dt_virt_base % SZ_2M); 1353 1354 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 1355 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 1356 1357 offset = dt_phys % SWAPPER_BLOCK_SIZE; 1358 dt_virt = (void *)dt_virt_base + offset; 1359 1360 /* map the first chunk so we can read the size from the header */ 1361 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 1362 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 1363 1364 if (fdt_magic(dt_virt) != FDT_MAGIC) 1365 return NULL; 1366 1367 *size = fdt_totalsize(dt_virt); 1368 if (*size > MAX_FDT_SIZE) 1369 return NULL; 1370 1371 if (offset + *size > SWAPPER_BLOCK_SIZE) 1372 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 1373 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 1374 1375 return dt_virt; 1376 } 1377 1378 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1379 { 1380 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1381 1382 /* Only allow permission changes for now */ 1383 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1384 pud_val(new_pud))) 1385 return 0; 1386 1387 VM_BUG_ON(phys & ~PUD_MASK); 1388 set_pud(pudp, new_pud); 1389 return 1; 1390 } 1391 1392 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1393 { 1394 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1395 1396 /* Only allow permission changes for now */ 1397 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1398 pmd_val(new_pmd))) 1399 return 0; 1400 1401 VM_BUG_ON(phys & ~PMD_MASK); 1402 set_pmd(pmdp, new_pmd); 1403 return 1; 1404 } 1405 1406 int pud_clear_huge(pud_t *pudp) 1407 { 1408 if (!pud_sect(READ_ONCE(*pudp))) 1409 return 0; 1410 pud_clear(pudp); 1411 return 1; 1412 } 1413 1414 int pmd_clear_huge(pmd_t *pmdp) 1415 { 1416 if (!pmd_sect(READ_ONCE(*pmdp))) 1417 return 0; 1418 pmd_clear(pmdp); 1419 return 1; 1420 } 1421 1422 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1423 { 1424 pte_t *table; 1425 pmd_t pmd; 1426 1427 pmd = READ_ONCE(*pmdp); 1428 1429 if (!pmd_table(pmd)) { 1430 VM_WARN_ON(1); 1431 return 1; 1432 } 1433 1434 table = pte_offset_kernel(pmdp, addr); 1435 pmd_clear(pmdp); 1436 __flush_tlb_kernel_pgtable(addr); 1437 pte_free_kernel(NULL, table); 1438 return 1; 1439 } 1440 1441 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1442 { 1443 pmd_t *table; 1444 pmd_t *pmdp; 1445 pud_t pud; 1446 unsigned long next, end; 1447 1448 pud = READ_ONCE(*pudp); 1449 1450 if (!pud_table(pud)) { 1451 VM_WARN_ON(1); 1452 return 1; 1453 } 1454 1455 table = pmd_offset(pudp, addr); 1456 pmdp = table; 1457 next = addr; 1458 end = addr + PUD_SIZE; 1459 do { 1460 pmd_free_pte_page(pmdp, next); 1461 } while (pmdp++, next += PMD_SIZE, next != end); 1462 1463 pud_clear(pudp); 1464 __flush_tlb_kernel_pgtable(addr); 1465 pmd_free(NULL, table); 1466 return 1; 1467 } 1468 1469 #ifdef CONFIG_MEMORY_HOTPLUG 1470 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1471 { 1472 unsigned long end = start + size; 1473 1474 WARN_ON(pgdir != init_mm.pgd); 1475 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1476 1477 unmap_hotplug_range(start, end, false, NULL); 1478 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1479 } 1480 1481 struct range arch_get_mappable_range(void) 1482 { 1483 struct range mhp_range; 1484 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1485 u64 end_linear_pa = __pa(PAGE_END - 1); 1486 1487 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1488 /* 1489 * Check for a wrap, it is possible because of randomized linear 1490 * mapping the start physical address is actually bigger than 1491 * the end physical address. In this case set start to zero 1492 * because [0, end_linear_pa] range must still be able to cover 1493 * all addressable physical addresses. 1494 */ 1495 if (start_linear_pa > end_linear_pa) 1496 start_linear_pa = 0; 1497 } 1498 1499 WARN_ON(start_linear_pa > end_linear_pa); 1500 1501 /* 1502 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1503 * accommodating both its ends but excluding PAGE_END. Max physical 1504 * range which can be mapped inside this linear mapping range, must 1505 * also be derived from its end points. 1506 */ 1507 mhp_range.start = start_linear_pa; 1508 mhp_range.end = end_linear_pa; 1509 1510 return mhp_range; 1511 } 1512 1513 int arch_add_memory(int nid, u64 start, u64 size, 1514 struct mhp_params *params) 1515 { 1516 int ret, flags = NO_EXEC_MAPPINGS; 1517 1518 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1519 1520 /* 1521 * KFENCE requires linear map to be mapped at page granularity, so that 1522 * it is possible to protect/unprotect single pages in the KFENCE pool. 1523 */ 1524 if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) 1525 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1526 1527 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1528 size, params->pgprot, __pgd_pgtable_alloc, 1529 flags); 1530 1531 memblock_clear_nomap(start, size); 1532 1533 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1534 params); 1535 if (ret) 1536 __remove_pgd_mapping(swapper_pg_dir, 1537 __phys_to_virt(start), size); 1538 else { 1539 max_pfn = PFN_UP(start + size); 1540 max_low_pfn = max_pfn; 1541 } 1542 1543 return ret; 1544 } 1545 1546 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1547 { 1548 unsigned long start_pfn = start >> PAGE_SHIFT; 1549 unsigned long nr_pages = size >> PAGE_SHIFT; 1550 1551 __remove_pages(start_pfn, nr_pages, altmap); 1552 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1553 } 1554 1555 /* 1556 * This memory hotplug notifier helps prevent boot memory from being 1557 * inadvertently removed as it blocks pfn range offlining process in 1558 * __offline_pages(). Hence this prevents both offlining as well as 1559 * removal process for boot memory which is initially always online. 1560 * In future if and when boot memory could be removed, this notifier 1561 * should be dropped and free_hotplug_page_range() should handle any 1562 * reserved pages allocated during boot. 1563 */ 1564 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1565 unsigned long action, void *data) 1566 { 1567 struct mem_section *ms; 1568 struct memory_notify *arg = data; 1569 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1570 unsigned long pfn = arg->start_pfn; 1571 1572 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1573 return NOTIFY_OK; 1574 1575 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1576 unsigned long start = PFN_PHYS(pfn); 1577 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1578 1579 ms = __pfn_to_section(pfn); 1580 if (!early_section(ms)) 1581 continue; 1582 1583 if (action == MEM_GOING_OFFLINE) { 1584 /* 1585 * Boot memory removal is not supported. Prevent 1586 * it via blocking any attempted offline request 1587 * for the boot memory and just report it. 1588 */ 1589 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1590 return NOTIFY_BAD; 1591 } else if (action == MEM_OFFLINE) { 1592 /* 1593 * This should have never happened. Boot memory 1594 * offlining should have been prevented by this 1595 * very notifier. Probably some memory removal 1596 * procedure might have changed which would then 1597 * require further debug. 1598 */ 1599 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1600 1601 /* 1602 * Core memory hotplug does not process a return 1603 * code from the notifier for MEM_OFFLINE events. 1604 * The error condition has been reported. Return 1605 * from here as if ignored. 1606 */ 1607 return NOTIFY_DONE; 1608 } 1609 } 1610 return NOTIFY_OK; 1611 } 1612 1613 static struct notifier_block prevent_bootmem_remove_nb = { 1614 .notifier_call = prevent_bootmem_remove_notifier, 1615 }; 1616 1617 /* 1618 * This ensures that boot memory sections on the platform are online 1619 * from early boot. Memory sections could not be prevented from being 1620 * offlined, unless for some reason they are not online to begin with. 1621 * This helps validate the basic assumption on which the above memory 1622 * event notifier works to prevent boot memory section offlining and 1623 * its possible removal. 1624 */ 1625 static void validate_bootmem_online(void) 1626 { 1627 phys_addr_t start, end, addr; 1628 struct mem_section *ms; 1629 u64 i; 1630 1631 /* 1632 * Scanning across all memblock might be expensive 1633 * on some big memory systems. Hence enable this 1634 * validation only with DEBUG_VM. 1635 */ 1636 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1637 return; 1638 1639 for_each_mem_range(i, &start, &end) { 1640 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1641 ms = __pfn_to_section(PHYS_PFN(addr)); 1642 1643 /* 1644 * All memory ranges in the system at this point 1645 * should have been marked as early sections. 1646 */ 1647 WARN_ON(!early_section(ms)); 1648 1649 /* 1650 * Memory notifier mechanism here to prevent boot 1651 * memory offlining depends on the fact that each 1652 * early section memory on the system is initially 1653 * online. Otherwise a given memory section which 1654 * is already offline will be overlooked and can 1655 * be removed completely. Call out such sections. 1656 */ 1657 if (!online_section(ms)) 1658 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1659 addr, addr + (1UL << PA_SECTION_SHIFT)); 1660 } 1661 } 1662 } 1663 1664 static int __init prevent_bootmem_remove_init(void) 1665 { 1666 int ret = 0; 1667 1668 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1669 return ret; 1670 1671 validate_bootmem_online(); 1672 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1673 if (ret) 1674 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1675 1676 return ret; 1677 } 1678 early_initcall(prevent_bootmem_remove_init); 1679 #endif 1680