1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Based on arch/arm/mm/mmu.c 4 * 5 * Copyright (C) 1995-2005 Russell King 6 * Copyright (C) 2012 ARM Ltd. 7 */ 8 9 #include <linux/cache.h> 10 #include <linux/export.h> 11 #include <linux/kernel.h> 12 #include <linux/errno.h> 13 #include <linux/init.h> 14 #include <linux/ioport.h> 15 #include <linux/kexec.h> 16 #include <linux/libfdt.h> 17 #include <linux/mman.h> 18 #include <linux/nodemask.h> 19 #include <linux/memblock.h> 20 #include <linux/memremap.h> 21 #include <linux/memory.h> 22 #include <linux/fs.h> 23 #include <linux/io.h> 24 #include <linux/mm.h> 25 #include <linux/vmalloc.h> 26 #include <linux/set_memory.h> 27 28 #include <asm/barrier.h> 29 #include <asm/cputype.h> 30 #include <asm/fixmap.h> 31 #include <asm/kasan.h> 32 #include <asm/kernel-pgtable.h> 33 #include <asm/sections.h> 34 #include <asm/setup.h> 35 #include <linux/sizes.h> 36 #include <asm/tlb.h> 37 #include <asm/mmu_context.h> 38 #include <asm/ptdump.h> 39 #include <asm/tlbflush.h> 40 #include <asm/pgalloc.h> 41 42 #define NO_BLOCK_MAPPINGS BIT(0) 43 #define NO_CONT_MAPPINGS BIT(1) 44 #define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */ 45 46 int idmap_t0sz __ro_after_init; 47 48 #if VA_BITS > 48 49 u64 vabits_actual __ro_after_init = VA_BITS_MIN; 50 EXPORT_SYMBOL(vabits_actual); 51 #endif 52 53 u64 kimage_vaddr __ro_after_init = (u64)&_text; 54 EXPORT_SYMBOL(kimage_vaddr); 55 56 u64 kimage_voffset __ro_after_init; 57 EXPORT_SYMBOL(kimage_voffset); 58 59 u32 __boot_cpu_mode[] = { BOOT_CPU_MODE_EL2, BOOT_CPU_MODE_EL1 }; 60 61 /* 62 * The booting CPU updates the failed status @__early_cpu_boot_status, 63 * with MMU turned off. 64 */ 65 long __section(".mmuoff.data.write") __early_cpu_boot_status; 66 67 /* 68 * Empty_zero_page is a special page that is used for zero-initialized data 69 * and COW. 70 */ 71 unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; 72 EXPORT_SYMBOL(empty_zero_page); 73 74 static pte_t bm_pte[PTRS_PER_PTE] __page_aligned_bss; 75 static pmd_t bm_pmd[PTRS_PER_PMD] __page_aligned_bss __maybe_unused; 76 static pud_t bm_pud[PTRS_PER_PUD] __page_aligned_bss __maybe_unused; 77 78 static DEFINE_SPINLOCK(swapper_pgdir_lock); 79 static DEFINE_MUTEX(fixmap_lock); 80 81 void set_swapper_pgd(pgd_t *pgdp, pgd_t pgd) 82 { 83 pgd_t *fixmap_pgdp; 84 85 spin_lock(&swapper_pgdir_lock); 86 fixmap_pgdp = pgd_set_fixmap(__pa_symbol(pgdp)); 87 WRITE_ONCE(*fixmap_pgdp, pgd); 88 /* 89 * We need dsb(ishst) here to ensure the page-table-walker sees 90 * our new entry before set_p?d() returns. The fixmap's 91 * flush_tlb_kernel_range() via clear_fixmap() does this for us. 92 */ 93 pgd_clear_fixmap(); 94 spin_unlock(&swapper_pgdir_lock); 95 } 96 97 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 98 unsigned long size, pgprot_t vma_prot) 99 { 100 if (!pfn_is_map_memory(pfn)) 101 return pgprot_noncached(vma_prot); 102 else if (file->f_flags & O_SYNC) 103 return pgprot_writecombine(vma_prot); 104 return vma_prot; 105 } 106 EXPORT_SYMBOL(phys_mem_access_prot); 107 108 static phys_addr_t __init early_pgtable_alloc(int shift) 109 { 110 phys_addr_t phys; 111 void *ptr; 112 113 phys = memblock_phys_alloc_range(PAGE_SIZE, PAGE_SIZE, 0, 114 MEMBLOCK_ALLOC_NOLEAKTRACE); 115 if (!phys) 116 panic("Failed to allocate page table page\n"); 117 118 /* 119 * The FIX_{PGD,PUD,PMD} slots may be in active use, but the FIX_PTE 120 * slot will be free, so we can (ab)use the FIX_PTE slot to initialise 121 * any level of table. 122 */ 123 ptr = pte_set_fixmap(phys); 124 125 memset(ptr, 0, PAGE_SIZE); 126 127 /* 128 * Implicit barriers also ensure the zeroed page is visible to the page 129 * table walker 130 */ 131 pte_clear_fixmap(); 132 133 return phys; 134 } 135 136 static bool pgattr_change_is_safe(u64 old, u64 new) 137 { 138 /* 139 * The following mapping attributes may be updated in live 140 * kernel mappings without the need for break-before-make. 141 */ 142 pteval_t mask = PTE_PXN | PTE_RDONLY | PTE_WRITE | PTE_NG; 143 144 /* creating or taking down mappings is always safe */ 145 if (old == 0 || new == 0) 146 return true; 147 148 /* live contiguous mappings may not be manipulated at all */ 149 if ((old | new) & PTE_CONT) 150 return false; 151 152 /* Transitioning from Non-Global to Global is unsafe */ 153 if (old & ~new & PTE_NG) 154 return false; 155 156 /* 157 * Changing the memory type between Normal and Normal-Tagged is safe 158 * since Tagged is considered a permission attribute from the 159 * mismatched attribute aliases perspective. 160 */ 161 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 162 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 163 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 164 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 165 mask |= PTE_ATTRINDX_MASK; 166 167 return ((old ^ new) & ~mask) == 0; 168 } 169 170 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 171 phys_addr_t phys, pgprot_t prot) 172 { 173 pte_t *ptep; 174 175 ptep = pte_set_fixmap_offset(pmdp, addr); 176 do { 177 pte_t old_pte = READ_ONCE(*ptep); 178 179 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 180 181 /* 182 * After the PTE entry has been populated once, we 183 * only allow updates to the permission attributes. 184 */ 185 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 186 READ_ONCE(pte_val(*ptep)))); 187 188 phys += PAGE_SIZE; 189 } while (ptep++, addr += PAGE_SIZE, addr != end); 190 191 pte_clear_fixmap(); 192 } 193 194 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 195 unsigned long end, phys_addr_t phys, 196 pgprot_t prot, 197 phys_addr_t (*pgtable_alloc)(int), 198 int flags) 199 { 200 unsigned long next; 201 pmd_t pmd = READ_ONCE(*pmdp); 202 203 BUG_ON(pmd_sect(pmd)); 204 if (pmd_none(pmd)) { 205 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN; 206 phys_addr_t pte_phys; 207 208 if (flags & NO_EXEC_MAPPINGS) 209 pmdval |= PMD_TABLE_PXN; 210 BUG_ON(!pgtable_alloc); 211 pte_phys = pgtable_alloc(PAGE_SHIFT); 212 __pmd_populate(pmdp, pte_phys, pmdval); 213 pmd = READ_ONCE(*pmdp); 214 } 215 BUG_ON(pmd_bad(pmd)); 216 217 do { 218 pgprot_t __prot = prot; 219 220 next = pte_cont_addr_end(addr, end); 221 222 /* use a contiguous mapping if the range is suitably aligned */ 223 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 224 (flags & NO_CONT_MAPPINGS) == 0) 225 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 226 227 init_pte(pmdp, addr, next, phys, __prot); 228 229 phys += next - addr; 230 } while (addr = next, addr != end); 231 } 232 233 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 234 phys_addr_t phys, pgprot_t prot, 235 phys_addr_t (*pgtable_alloc)(int), int flags) 236 { 237 unsigned long next; 238 pmd_t *pmdp; 239 240 pmdp = pmd_set_fixmap_offset(pudp, addr); 241 do { 242 pmd_t old_pmd = READ_ONCE(*pmdp); 243 244 next = pmd_addr_end(addr, end); 245 246 /* try section mapping first */ 247 if (((addr | next | phys) & ~PMD_MASK) == 0 && 248 (flags & NO_BLOCK_MAPPINGS) == 0) { 249 pmd_set_huge(pmdp, phys, prot); 250 251 /* 252 * After the PMD entry has been populated once, we 253 * only allow updates to the permission attributes. 254 */ 255 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 256 READ_ONCE(pmd_val(*pmdp)))); 257 } else { 258 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 259 pgtable_alloc, flags); 260 261 BUG_ON(pmd_val(old_pmd) != 0 && 262 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 263 } 264 phys += next - addr; 265 } while (pmdp++, addr = next, addr != end); 266 267 pmd_clear_fixmap(); 268 } 269 270 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 271 unsigned long end, phys_addr_t phys, 272 pgprot_t prot, 273 phys_addr_t (*pgtable_alloc)(int), int flags) 274 { 275 unsigned long next; 276 pud_t pud = READ_ONCE(*pudp); 277 278 /* 279 * Check for initial section mappings in the pgd/pud. 280 */ 281 BUG_ON(pud_sect(pud)); 282 if (pud_none(pud)) { 283 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN; 284 phys_addr_t pmd_phys; 285 286 if (flags & NO_EXEC_MAPPINGS) 287 pudval |= PUD_TABLE_PXN; 288 BUG_ON(!pgtable_alloc); 289 pmd_phys = pgtable_alloc(PMD_SHIFT); 290 __pud_populate(pudp, pmd_phys, pudval); 291 pud = READ_ONCE(*pudp); 292 } 293 BUG_ON(pud_bad(pud)); 294 295 do { 296 pgprot_t __prot = prot; 297 298 next = pmd_cont_addr_end(addr, end); 299 300 /* use a contiguous mapping if the range is suitably aligned */ 301 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 302 (flags & NO_CONT_MAPPINGS) == 0) 303 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 304 305 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 306 307 phys += next - addr; 308 } while (addr = next, addr != end); 309 } 310 311 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 312 phys_addr_t phys, pgprot_t prot, 313 phys_addr_t (*pgtable_alloc)(int), 314 int flags) 315 { 316 unsigned long next; 317 pud_t *pudp; 318 p4d_t *p4dp = p4d_offset(pgdp, addr); 319 p4d_t p4d = READ_ONCE(*p4dp); 320 321 if (p4d_none(p4d)) { 322 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN; 323 phys_addr_t pud_phys; 324 325 if (flags & NO_EXEC_MAPPINGS) 326 p4dval |= P4D_TABLE_PXN; 327 BUG_ON(!pgtable_alloc); 328 pud_phys = pgtable_alloc(PUD_SHIFT); 329 __p4d_populate(p4dp, pud_phys, p4dval); 330 p4d = READ_ONCE(*p4dp); 331 } 332 BUG_ON(p4d_bad(p4d)); 333 334 /* 335 * No need for locking during early boot. And it doesn't work as 336 * expected with KASLR enabled. 337 */ 338 if (system_state != SYSTEM_BOOTING) 339 mutex_lock(&fixmap_lock); 340 pudp = pud_set_fixmap_offset(p4dp, addr); 341 do { 342 pud_t old_pud = READ_ONCE(*pudp); 343 344 next = pud_addr_end(addr, end); 345 346 /* 347 * For 4K granule only, attempt to put down a 1GB block 348 */ 349 if (pud_sect_supported() && 350 ((addr | next | phys) & ~PUD_MASK) == 0 && 351 (flags & NO_BLOCK_MAPPINGS) == 0) { 352 pud_set_huge(pudp, phys, prot); 353 354 /* 355 * After the PUD entry has been populated once, we 356 * only allow updates to the permission attributes. 357 */ 358 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 359 READ_ONCE(pud_val(*pudp)))); 360 } else { 361 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 362 pgtable_alloc, flags); 363 364 BUG_ON(pud_val(old_pud) != 0 && 365 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 366 } 367 phys += next - addr; 368 } while (pudp++, addr = next, addr != end); 369 370 pud_clear_fixmap(); 371 if (system_state != SYSTEM_BOOTING) 372 mutex_unlock(&fixmap_lock); 373 } 374 375 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 376 unsigned long virt, phys_addr_t size, 377 pgprot_t prot, 378 phys_addr_t (*pgtable_alloc)(int), 379 int flags) 380 { 381 unsigned long addr, end, next; 382 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 383 384 /* 385 * If the virtual and physical address don't have the same offset 386 * within a page, we cannot map the region as the caller expects. 387 */ 388 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 389 return; 390 391 phys &= PAGE_MASK; 392 addr = virt & PAGE_MASK; 393 end = PAGE_ALIGN(virt + size); 394 395 do { 396 next = pgd_addr_end(addr, end); 397 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 398 flags); 399 phys += next - addr; 400 } while (pgdp++, addr = next, addr != end); 401 } 402 403 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 404 extern __alias(__create_pgd_mapping) 405 void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, 406 phys_addr_t size, pgprot_t prot, 407 phys_addr_t (*pgtable_alloc)(int), int flags); 408 #endif 409 410 static phys_addr_t __pgd_pgtable_alloc(int shift) 411 { 412 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 413 BUG_ON(!ptr); 414 415 /* Ensure the zeroed page is visible to the page table walker */ 416 dsb(ishst); 417 return __pa(ptr); 418 } 419 420 static phys_addr_t pgd_pgtable_alloc(int shift) 421 { 422 phys_addr_t pa = __pgd_pgtable_alloc(shift); 423 424 /* 425 * Call proper page table ctor in case later we need to 426 * call core mm functions like apply_to_page_range() on 427 * this pre-allocated page table. 428 * 429 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 430 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 431 */ 432 if (shift == PAGE_SHIFT) 433 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 434 else if (shift == PMD_SHIFT) 435 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 436 437 return pa; 438 } 439 440 /* 441 * This function can only be used to modify existing table entries, 442 * without allocating new levels of table. Note that this permits the 443 * creation of new section or page entries. 444 */ 445 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 446 phys_addr_t size, pgprot_t prot) 447 { 448 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 449 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 450 &phys, virt); 451 return; 452 } 453 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 454 NO_CONT_MAPPINGS); 455 } 456 457 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 458 unsigned long virt, phys_addr_t size, 459 pgprot_t prot, bool page_mappings_only) 460 { 461 int flags = 0; 462 463 BUG_ON(mm == &init_mm); 464 465 if (page_mappings_only) 466 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 467 468 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 469 pgd_pgtable_alloc, flags); 470 } 471 472 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 473 phys_addr_t size, pgprot_t prot) 474 { 475 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 476 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 477 &phys, virt); 478 return; 479 } 480 481 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 482 NO_CONT_MAPPINGS); 483 484 /* flush the TLBs after updating live kernel mappings */ 485 flush_tlb_kernel_range(virt, virt + size); 486 } 487 488 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 489 phys_addr_t end, pgprot_t prot, int flags) 490 { 491 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 492 prot, early_pgtable_alloc, flags); 493 } 494 495 void __init mark_linear_text_alias_ro(void) 496 { 497 /* 498 * Remove the write permissions from the linear alias of .text/.rodata 499 */ 500 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext), 501 (unsigned long)__init_begin - (unsigned long)_stext, 502 PAGE_KERNEL_RO); 503 } 504 505 static bool crash_mem_map __initdata; 506 507 static int __init enable_crash_mem_map(char *arg) 508 { 509 /* 510 * Proper parameter parsing is done by reserve_crashkernel(). We only 511 * need to know if the linear map has to avoid block mappings so that 512 * the crashkernel reservations can be unmapped later. 513 */ 514 crash_mem_map = true; 515 516 return 0; 517 } 518 early_param("crashkernel", enable_crash_mem_map); 519 520 static void __init map_mem(pgd_t *pgdp) 521 { 522 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 523 phys_addr_t kernel_start = __pa_symbol(_stext); 524 phys_addr_t kernel_end = __pa_symbol(__init_begin); 525 phys_addr_t start, end; 526 int flags = NO_EXEC_MAPPINGS; 527 u64 i; 528 529 /* 530 * Setting hierarchical PXNTable attributes on table entries covering 531 * the linear region is only possible if it is guaranteed that no table 532 * entries at any level are being shared between the linear region and 533 * the vmalloc region. Check whether this is true for the PGD level, in 534 * which case it is guaranteed to be true for all other levels as well. 535 */ 536 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); 537 538 if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) 539 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 540 541 /* 542 * Take care not to create a writable alias for the 543 * read-only text and rodata sections of the kernel image. 544 * So temporarily mark them as NOMAP to skip mappings in 545 * the following for-loop 546 */ 547 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 548 549 #ifdef CONFIG_KEXEC_CORE 550 if (crash_mem_map) { 551 if (defer_reserve_crashkernel()) 552 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 553 else if (crashk_res.end) 554 memblock_mark_nomap(crashk_res.start, 555 resource_size(&crashk_res)); 556 } 557 #endif 558 559 /* map all the memory banks */ 560 for_each_mem_range(i, &start, &end) { 561 if (start >= end) 562 break; 563 /* 564 * The linear map must allow allocation tags reading/writing 565 * if MTE is present. Otherwise, it has the same attributes as 566 * PAGE_KERNEL. 567 */ 568 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 569 flags); 570 } 571 572 /* 573 * Map the linear alias of the [_stext, __init_begin) interval 574 * as non-executable now, and remove the write permission in 575 * mark_linear_text_alias_ro() below (which will be called after 576 * alternative patching has completed). This makes the contents 577 * of the region accessible to subsystems such as hibernate, 578 * but protects it from inadvertent modification or execution. 579 * Note that contiguous mappings cannot be remapped in this way, 580 * so we should avoid them here. 581 */ 582 __map_memblock(pgdp, kernel_start, kernel_end, 583 PAGE_KERNEL, NO_CONT_MAPPINGS); 584 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 585 586 /* 587 * Use page-level mappings here so that we can shrink the region 588 * in page granularity and put back unused memory to buddy system 589 * through /sys/kernel/kexec_crash_size interface. 590 */ 591 #ifdef CONFIG_KEXEC_CORE 592 if (crash_mem_map && !defer_reserve_crashkernel()) { 593 if (crashk_res.end) { 594 __map_memblock(pgdp, crashk_res.start, 595 crashk_res.end + 1, 596 PAGE_KERNEL, 597 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 598 memblock_clear_nomap(crashk_res.start, 599 resource_size(&crashk_res)); 600 } 601 } 602 #endif 603 } 604 605 void mark_rodata_ro(void) 606 { 607 unsigned long section_size; 608 609 /* 610 * mark .rodata as read only. Use __init_begin rather than __end_rodata 611 * to cover NOTES and EXCEPTION_TABLE. 612 */ 613 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 614 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 615 section_size, PAGE_KERNEL_RO); 616 617 debug_checkwx(); 618 } 619 620 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 621 pgprot_t prot, struct vm_struct *vma, 622 int flags, unsigned long vm_flags) 623 { 624 phys_addr_t pa_start = __pa_symbol(va_start); 625 unsigned long size = va_end - va_start; 626 627 BUG_ON(!PAGE_ALIGNED(pa_start)); 628 BUG_ON(!PAGE_ALIGNED(size)); 629 630 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 631 early_pgtable_alloc, flags); 632 633 if (!(vm_flags & VM_NO_GUARD)) 634 size += PAGE_SIZE; 635 636 vma->addr = va_start; 637 vma->phys_addr = pa_start; 638 vma->size = size; 639 vma->flags = VM_MAP | vm_flags; 640 vma->caller = __builtin_return_address(0); 641 642 vm_area_add_early(vma); 643 } 644 645 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 646 static int __init map_entry_trampoline(void) 647 { 648 int i; 649 650 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 651 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 652 653 /* The trampoline is always mapped and can therefore be global */ 654 pgprot_val(prot) &= ~PTE_NG; 655 656 /* Map only the text into the trampoline page table */ 657 memset(tramp_pg_dir, 0, PGD_SIZE); 658 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 659 entry_tramp_text_size(), prot, 660 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 661 662 /* Map both the text and data into the kernel page table */ 663 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 664 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 665 pa_start + i * PAGE_SIZE, prot); 666 667 if (IS_ENABLED(CONFIG_RELOCATABLE)) 668 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 669 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 670 671 return 0; 672 } 673 core_initcall(map_entry_trampoline); 674 #endif 675 676 /* 677 * Open coded check for BTI, only for use to determine configuration 678 * for early mappings for before the cpufeature code has run. 679 */ 680 static bool arm64_early_this_cpu_has_bti(void) 681 { 682 u64 pfr1; 683 684 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 685 return false; 686 687 pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1); 688 return cpuid_feature_extract_unsigned_field(pfr1, 689 ID_AA64PFR1_BT_SHIFT); 690 } 691 692 /* 693 * Create fine-grained mappings for the kernel. 694 */ 695 static void __init map_kernel(pgd_t *pgdp) 696 { 697 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 698 vmlinux_initdata, vmlinux_data; 699 700 /* 701 * External debuggers may need to write directly to the text 702 * mapping to install SW breakpoints. Allow this (only) when 703 * explicitly requested with rodata=off. 704 */ 705 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 706 707 /* 708 * If we have a CPU that supports BTI and a kernel built for 709 * BTI then mark the kernel executable text as guarded pages 710 * now so we don't have to rewrite the page tables later. 711 */ 712 if (arm64_early_this_cpu_has_bti()) 713 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 714 715 /* 716 * Only rodata will be remapped with different permissions later on, 717 * all other segments are allowed to use contiguous mappings. 718 */ 719 map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0, 720 VM_NO_GUARD); 721 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 722 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 723 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 724 &vmlinux_inittext, 0, VM_NO_GUARD); 725 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 726 &vmlinux_initdata, 0, VM_NO_GUARD); 727 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 728 729 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { 730 /* 731 * The fixmap falls in a separate pgd to the kernel, and doesn't 732 * live in the carveout for the swapper_pg_dir. We can simply 733 * re-use the existing dir for the fixmap. 734 */ 735 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), 736 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 737 } else if (CONFIG_PGTABLE_LEVELS > 3) { 738 pgd_t *bm_pgdp; 739 p4d_t *bm_p4dp; 740 pud_t *bm_pudp; 741 /* 742 * The fixmap shares its top level pgd entry with the kernel 743 * mapping. This can really only occur when we are running 744 * with 16k/4 levels, so we can simply reuse the pud level 745 * entry instead. 746 */ 747 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 748 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); 749 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); 750 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); 751 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 752 pud_clear_fixmap(); 753 } else { 754 BUG(); 755 } 756 757 kasan_copy_shadow(pgdp); 758 } 759 760 static void __init create_idmap(void) 761 { 762 u64 start = __pa_symbol(__idmap_text_start); 763 u64 size = __pa_symbol(__idmap_text_end) - start; 764 pgd_t *pgd = idmap_pg_dir; 765 u64 pgd_phys; 766 767 /* check if we need an additional level of translation */ 768 if (VA_BITS < 48 && idmap_t0sz < (64 - VA_BITS_MIN)) { 769 pgd_phys = early_pgtable_alloc(PAGE_SHIFT); 770 set_pgd(&idmap_pg_dir[start >> VA_BITS], 771 __pgd(pgd_phys | P4D_TYPE_TABLE)); 772 pgd = __va(pgd_phys); 773 } 774 __create_pgd_mapping(pgd, start, start, size, PAGE_KERNEL_ROX, 775 early_pgtable_alloc, 0); 776 777 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) { 778 extern u32 __idmap_kpti_flag; 779 u64 pa = __pa_symbol(&__idmap_kpti_flag); 780 781 /* 782 * The KPTI G-to-nG conversion code needs a read-write mapping 783 * of its synchronization flag in the ID map. 784 */ 785 __create_pgd_mapping(pgd, pa, pa, sizeof(u32), PAGE_KERNEL, 786 early_pgtable_alloc, 0); 787 } 788 } 789 790 void __init paging_init(void) 791 { 792 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 793 extern pgd_t init_idmap_pg_dir[]; 794 795 idmap_t0sz = 63UL - __fls(__pa_symbol(_end) | GENMASK(VA_BITS_MIN - 1, 0)); 796 797 map_kernel(pgdp); 798 map_mem(pgdp); 799 800 pgd_clear_fixmap(); 801 802 cpu_replace_ttbr1(lm_alias(swapper_pg_dir), init_idmap_pg_dir); 803 init_mm.pgd = swapper_pg_dir; 804 805 memblock_phys_free(__pa_symbol(init_pg_dir), 806 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 807 808 memblock_allow_resize(); 809 810 create_idmap(); 811 } 812 813 /* 814 * Check whether a kernel address is valid (derived from arch/x86/). 815 */ 816 int kern_addr_valid(unsigned long addr) 817 { 818 pgd_t *pgdp; 819 p4d_t *p4dp; 820 pud_t *pudp, pud; 821 pmd_t *pmdp, pmd; 822 pte_t *ptep, pte; 823 824 addr = arch_kasan_reset_tag(addr); 825 if ((((long)addr) >> VA_BITS) != -1UL) 826 return 0; 827 828 pgdp = pgd_offset_k(addr); 829 if (pgd_none(READ_ONCE(*pgdp))) 830 return 0; 831 832 p4dp = p4d_offset(pgdp, addr); 833 if (p4d_none(READ_ONCE(*p4dp))) 834 return 0; 835 836 pudp = pud_offset(p4dp, addr); 837 pud = READ_ONCE(*pudp); 838 if (pud_none(pud)) 839 return 0; 840 841 if (pud_sect(pud)) 842 return pfn_valid(pud_pfn(pud)); 843 844 pmdp = pmd_offset(pudp, addr); 845 pmd = READ_ONCE(*pmdp); 846 if (pmd_none(pmd)) 847 return 0; 848 849 if (pmd_sect(pmd)) 850 return pfn_valid(pmd_pfn(pmd)); 851 852 ptep = pte_offset_kernel(pmdp, addr); 853 pte = READ_ONCE(*ptep); 854 if (pte_none(pte)) 855 return 0; 856 857 return pfn_valid(pte_pfn(pte)); 858 } 859 860 #ifdef CONFIG_MEMORY_HOTPLUG 861 static void free_hotplug_page_range(struct page *page, size_t size, 862 struct vmem_altmap *altmap) 863 { 864 if (altmap) { 865 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 866 } else { 867 WARN_ON(PageReserved(page)); 868 free_pages((unsigned long)page_address(page), get_order(size)); 869 } 870 } 871 872 static void free_hotplug_pgtable_page(struct page *page) 873 { 874 free_hotplug_page_range(page, PAGE_SIZE, NULL); 875 } 876 877 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 878 unsigned long floor, unsigned long ceiling, 879 unsigned long mask) 880 { 881 start &= mask; 882 if (start < floor) 883 return false; 884 885 if (ceiling) { 886 ceiling &= mask; 887 if (!ceiling) 888 return false; 889 } 890 891 if (end - 1 > ceiling - 1) 892 return false; 893 return true; 894 } 895 896 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 897 unsigned long end, bool free_mapped, 898 struct vmem_altmap *altmap) 899 { 900 pte_t *ptep, pte; 901 902 do { 903 ptep = pte_offset_kernel(pmdp, addr); 904 pte = READ_ONCE(*ptep); 905 if (pte_none(pte)) 906 continue; 907 908 WARN_ON(!pte_present(pte)); 909 pte_clear(&init_mm, addr, ptep); 910 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 911 if (free_mapped) 912 free_hotplug_page_range(pte_page(pte), 913 PAGE_SIZE, altmap); 914 } while (addr += PAGE_SIZE, addr < end); 915 } 916 917 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 918 unsigned long end, bool free_mapped, 919 struct vmem_altmap *altmap) 920 { 921 unsigned long next; 922 pmd_t *pmdp, pmd; 923 924 do { 925 next = pmd_addr_end(addr, end); 926 pmdp = pmd_offset(pudp, addr); 927 pmd = READ_ONCE(*pmdp); 928 if (pmd_none(pmd)) 929 continue; 930 931 WARN_ON(!pmd_present(pmd)); 932 if (pmd_sect(pmd)) { 933 pmd_clear(pmdp); 934 935 /* 936 * One TLBI should be sufficient here as the PMD_SIZE 937 * range is mapped with a single block entry. 938 */ 939 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 940 if (free_mapped) 941 free_hotplug_page_range(pmd_page(pmd), 942 PMD_SIZE, altmap); 943 continue; 944 } 945 WARN_ON(!pmd_table(pmd)); 946 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 947 } while (addr = next, addr < end); 948 } 949 950 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 951 unsigned long end, bool free_mapped, 952 struct vmem_altmap *altmap) 953 { 954 unsigned long next; 955 pud_t *pudp, pud; 956 957 do { 958 next = pud_addr_end(addr, end); 959 pudp = pud_offset(p4dp, addr); 960 pud = READ_ONCE(*pudp); 961 if (pud_none(pud)) 962 continue; 963 964 WARN_ON(!pud_present(pud)); 965 if (pud_sect(pud)) { 966 pud_clear(pudp); 967 968 /* 969 * One TLBI should be sufficient here as the PUD_SIZE 970 * range is mapped with a single block entry. 971 */ 972 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 973 if (free_mapped) 974 free_hotplug_page_range(pud_page(pud), 975 PUD_SIZE, altmap); 976 continue; 977 } 978 WARN_ON(!pud_table(pud)); 979 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 980 } while (addr = next, addr < end); 981 } 982 983 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 984 unsigned long end, bool free_mapped, 985 struct vmem_altmap *altmap) 986 { 987 unsigned long next; 988 p4d_t *p4dp, p4d; 989 990 do { 991 next = p4d_addr_end(addr, end); 992 p4dp = p4d_offset(pgdp, addr); 993 p4d = READ_ONCE(*p4dp); 994 if (p4d_none(p4d)) 995 continue; 996 997 WARN_ON(!p4d_present(p4d)); 998 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 999 } while (addr = next, addr < end); 1000 } 1001 1002 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 1003 bool free_mapped, struct vmem_altmap *altmap) 1004 { 1005 unsigned long next; 1006 pgd_t *pgdp, pgd; 1007 1008 /* 1009 * altmap can only be used as vmemmap mapping backing memory. 1010 * In case the backing memory itself is not being freed, then 1011 * altmap is irrelevant. Warn about this inconsistency when 1012 * encountered. 1013 */ 1014 WARN_ON(!free_mapped && altmap); 1015 1016 do { 1017 next = pgd_addr_end(addr, end); 1018 pgdp = pgd_offset_k(addr); 1019 pgd = READ_ONCE(*pgdp); 1020 if (pgd_none(pgd)) 1021 continue; 1022 1023 WARN_ON(!pgd_present(pgd)); 1024 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 1025 } while (addr = next, addr < end); 1026 } 1027 1028 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 1029 unsigned long end, unsigned long floor, 1030 unsigned long ceiling) 1031 { 1032 pte_t *ptep, pte; 1033 unsigned long i, start = addr; 1034 1035 do { 1036 ptep = pte_offset_kernel(pmdp, addr); 1037 pte = READ_ONCE(*ptep); 1038 1039 /* 1040 * This is just a sanity check here which verifies that 1041 * pte clearing has been done by earlier unmap loops. 1042 */ 1043 WARN_ON(!pte_none(pte)); 1044 } while (addr += PAGE_SIZE, addr < end); 1045 1046 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1047 return; 1048 1049 /* 1050 * Check whether we can free the pte page if the rest of the 1051 * entries are empty. Overlap with other regions have been 1052 * handled by the floor/ceiling check. 1053 */ 1054 ptep = pte_offset_kernel(pmdp, 0UL); 1055 for (i = 0; i < PTRS_PER_PTE; i++) { 1056 if (!pte_none(READ_ONCE(ptep[i]))) 1057 return; 1058 } 1059 1060 pmd_clear(pmdp); 1061 __flush_tlb_kernel_pgtable(start); 1062 free_hotplug_pgtable_page(virt_to_page(ptep)); 1063 } 1064 1065 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1066 unsigned long end, unsigned long floor, 1067 unsigned long ceiling) 1068 { 1069 pmd_t *pmdp, pmd; 1070 unsigned long i, next, start = addr; 1071 1072 do { 1073 next = pmd_addr_end(addr, end); 1074 pmdp = pmd_offset(pudp, addr); 1075 pmd = READ_ONCE(*pmdp); 1076 if (pmd_none(pmd)) 1077 continue; 1078 1079 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1080 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1081 } while (addr = next, addr < end); 1082 1083 if (CONFIG_PGTABLE_LEVELS <= 2) 1084 return; 1085 1086 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1087 return; 1088 1089 /* 1090 * Check whether we can free the pmd page if the rest of the 1091 * entries are empty. Overlap with other regions have been 1092 * handled by the floor/ceiling check. 1093 */ 1094 pmdp = pmd_offset(pudp, 0UL); 1095 for (i = 0; i < PTRS_PER_PMD; i++) { 1096 if (!pmd_none(READ_ONCE(pmdp[i]))) 1097 return; 1098 } 1099 1100 pud_clear(pudp); 1101 __flush_tlb_kernel_pgtable(start); 1102 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1103 } 1104 1105 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1106 unsigned long end, unsigned long floor, 1107 unsigned long ceiling) 1108 { 1109 pud_t *pudp, pud; 1110 unsigned long i, next, start = addr; 1111 1112 do { 1113 next = pud_addr_end(addr, end); 1114 pudp = pud_offset(p4dp, addr); 1115 pud = READ_ONCE(*pudp); 1116 if (pud_none(pud)) 1117 continue; 1118 1119 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1120 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1121 } while (addr = next, addr < end); 1122 1123 if (CONFIG_PGTABLE_LEVELS <= 3) 1124 return; 1125 1126 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1127 return; 1128 1129 /* 1130 * Check whether we can free the pud page if the rest of the 1131 * entries are empty. Overlap with other regions have been 1132 * handled by the floor/ceiling check. 1133 */ 1134 pudp = pud_offset(p4dp, 0UL); 1135 for (i = 0; i < PTRS_PER_PUD; i++) { 1136 if (!pud_none(READ_ONCE(pudp[i]))) 1137 return; 1138 } 1139 1140 p4d_clear(p4dp); 1141 __flush_tlb_kernel_pgtable(start); 1142 free_hotplug_pgtable_page(virt_to_page(pudp)); 1143 } 1144 1145 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1146 unsigned long end, unsigned long floor, 1147 unsigned long ceiling) 1148 { 1149 unsigned long next; 1150 p4d_t *p4dp, p4d; 1151 1152 do { 1153 next = p4d_addr_end(addr, end); 1154 p4dp = p4d_offset(pgdp, addr); 1155 p4d = READ_ONCE(*p4dp); 1156 if (p4d_none(p4d)) 1157 continue; 1158 1159 WARN_ON(!p4d_present(p4d)); 1160 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1161 } while (addr = next, addr < end); 1162 } 1163 1164 static void free_empty_tables(unsigned long addr, unsigned long end, 1165 unsigned long floor, unsigned long ceiling) 1166 { 1167 unsigned long next; 1168 pgd_t *pgdp, pgd; 1169 1170 do { 1171 next = pgd_addr_end(addr, end); 1172 pgdp = pgd_offset_k(addr); 1173 pgd = READ_ONCE(*pgdp); 1174 if (pgd_none(pgd)) 1175 continue; 1176 1177 WARN_ON(!pgd_present(pgd)); 1178 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1179 } while (addr = next, addr < end); 1180 } 1181 #endif 1182 1183 #if !ARM64_KERNEL_USES_PMD_MAPS 1184 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1185 struct vmem_altmap *altmap) 1186 { 1187 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1188 return vmemmap_populate_basepages(start, end, node, altmap); 1189 } 1190 #else /* !ARM64_KERNEL_USES_PMD_MAPS */ 1191 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1192 struct vmem_altmap *altmap) 1193 { 1194 unsigned long addr = start; 1195 unsigned long next; 1196 pgd_t *pgdp; 1197 p4d_t *p4dp; 1198 pud_t *pudp; 1199 pmd_t *pmdp; 1200 1201 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1202 do { 1203 next = pmd_addr_end(addr, end); 1204 1205 pgdp = vmemmap_pgd_populate(addr, node); 1206 if (!pgdp) 1207 return -ENOMEM; 1208 1209 p4dp = vmemmap_p4d_populate(pgdp, addr, node); 1210 if (!p4dp) 1211 return -ENOMEM; 1212 1213 pudp = vmemmap_pud_populate(p4dp, addr, node); 1214 if (!pudp) 1215 return -ENOMEM; 1216 1217 pmdp = pmd_offset(pudp, addr); 1218 if (pmd_none(READ_ONCE(*pmdp))) { 1219 void *p = NULL; 1220 1221 p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); 1222 if (!p) { 1223 if (vmemmap_populate_basepages(addr, next, node, altmap)) 1224 return -ENOMEM; 1225 continue; 1226 } 1227 1228 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1229 } else 1230 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1231 } while (addr = next, addr != end); 1232 1233 return 0; 1234 } 1235 #endif /* !ARM64_KERNEL_USES_PMD_MAPS */ 1236 1237 #ifdef CONFIG_MEMORY_HOTPLUG 1238 void vmemmap_free(unsigned long start, unsigned long end, 1239 struct vmem_altmap *altmap) 1240 { 1241 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1242 1243 unmap_hotplug_range(start, end, true, altmap); 1244 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1245 } 1246 #endif /* CONFIG_MEMORY_HOTPLUG */ 1247 1248 static inline pud_t *fixmap_pud(unsigned long addr) 1249 { 1250 pgd_t *pgdp = pgd_offset_k(addr); 1251 p4d_t *p4dp = p4d_offset(pgdp, addr); 1252 p4d_t p4d = READ_ONCE(*p4dp); 1253 1254 BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); 1255 1256 return pud_offset_kimg(p4dp, addr); 1257 } 1258 1259 static inline pmd_t *fixmap_pmd(unsigned long addr) 1260 { 1261 pud_t *pudp = fixmap_pud(addr); 1262 pud_t pud = READ_ONCE(*pudp); 1263 1264 BUG_ON(pud_none(pud) || pud_bad(pud)); 1265 1266 return pmd_offset_kimg(pudp, addr); 1267 } 1268 1269 static inline pte_t *fixmap_pte(unsigned long addr) 1270 { 1271 return &bm_pte[pte_index(addr)]; 1272 } 1273 1274 /* 1275 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 1276 * directly on kernel symbols (bm_p*d). This function is called too early to use 1277 * lm_alias so __p*d_populate functions must be used to populate with the 1278 * physical address from __pa_symbol. 1279 */ 1280 void __init early_fixmap_init(void) 1281 { 1282 pgd_t *pgdp; 1283 p4d_t *p4dp, p4d; 1284 pud_t *pudp; 1285 pmd_t *pmdp; 1286 unsigned long addr = FIXADDR_START; 1287 1288 pgdp = pgd_offset_k(addr); 1289 p4dp = p4d_offset(pgdp, addr); 1290 p4d = READ_ONCE(*p4dp); 1291 if (CONFIG_PGTABLE_LEVELS > 3 && 1292 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { 1293 /* 1294 * We only end up here if the kernel mapping and the fixmap 1295 * share the top level pgd entry, which should only happen on 1296 * 16k/4 levels configurations. 1297 */ 1298 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 1299 pudp = pud_offset_kimg(p4dp, addr); 1300 } else { 1301 if (p4d_none(p4d)) 1302 __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); 1303 pudp = fixmap_pud(addr); 1304 } 1305 if (pud_none(READ_ONCE(*pudp))) 1306 __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); 1307 pmdp = fixmap_pmd(addr); 1308 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 1309 1310 /* 1311 * The boot-ioremap range spans multiple pmds, for which 1312 * we are not prepared: 1313 */ 1314 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 1315 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 1316 1317 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 1318 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 1319 WARN_ON(1); 1320 pr_warn("pmdp %p != %p, %p\n", 1321 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 1322 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 1323 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 1324 fix_to_virt(FIX_BTMAP_BEGIN)); 1325 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 1326 fix_to_virt(FIX_BTMAP_END)); 1327 1328 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 1329 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 1330 } 1331 } 1332 1333 /* 1334 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 1335 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 1336 */ 1337 void __set_fixmap(enum fixed_addresses idx, 1338 phys_addr_t phys, pgprot_t flags) 1339 { 1340 unsigned long addr = __fix_to_virt(idx); 1341 pte_t *ptep; 1342 1343 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 1344 1345 ptep = fixmap_pte(addr); 1346 1347 if (pgprot_val(flags)) { 1348 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 1349 } else { 1350 pte_clear(&init_mm, addr, ptep); 1351 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 1352 } 1353 } 1354 1355 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 1356 { 1357 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 1358 int offset; 1359 void *dt_virt; 1360 1361 /* 1362 * Check whether the physical FDT address is set and meets the minimum 1363 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 1364 * at least 8 bytes so that we can always access the magic and size 1365 * fields of the FDT header after mapping the first chunk, double check 1366 * here if that is indeed the case. 1367 */ 1368 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 1369 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 1370 return NULL; 1371 1372 /* 1373 * Make sure that the FDT region can be mapped without the need to 1374 * allocate additional translation table pages, so that it is safe 1375 * to call create_mapping_noalloc() this early. 1376 * 1377 * On 64k pages, the FDT will be mapped using PTEs, so we need to 1378 * be in the same PMD as the rest of the fixmap. 1379 * On 4k pages, we'll use section mappings for the FDT so we only 1380 * have to be in the same PUD. 1381 */ 1382 BUILD_BUG_ON(dt_virt_base % SZ_2M); 1383 1384 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 1385 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 1386 1387 offset = dt_phys % SWAPPER_BLOCK_SIZE; 1388 dt_virt = (void *)dt_virt_base + offset; 1389 1390 /* map the first chunk so we can read the size from the header */ 1391 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 1392 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 1393 1394 if (fdt_magic(dt_virt) != FDT_MAGIC) 1395 return NULL; 1396 1397 *size = fdt_totalsize(dt_virt); 1398 if (*size > MAX_FDT_SIZE) 1399 return NULL; 1400 1401 if (offset + *size > SWAPPER_BLOCK_SIZE) 1402 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 1403 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 1404 1405 return dt_virt; 1406 } 1407 1408 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1409 { 1410 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1411 1412 /* Only allow permission changes for now */ 1413 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1414 pud_val(new_pud))) 1415 return 0; 1416 1417 VM_BUG_ON(phys & ~PUD_MASK); 1418 set_pud(pudp, new_pud); 1419 return 1; 1420 } 1421 1422 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1423 { 1424 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1425 1426 /* Only allow permission changes for now */ 1427 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1428 pmd_val(new_pmd))) 1429 return 0; 1430 1431 VM_BUG_ON(phys & ~PMD_MASK); 1432 set_pmd(pmdp, new_pmd); 1433 return 1; 1434 } 1435 1436 int pud_clear_huge(pud_t *pudp) 1437 { 1438 if (!pud_sect(READ_ONCE(*pudp))) 1439 return 0; 1440 pud_clear(pudp); 1441 return 1; 1442 } 1443 1444 int pmd_clear_huge(pmd_t *pmdp) 1445 { 1446 if (!pmd_sect(READ_ONCE(*pmdp))) 1447 return 0; 1448 pmd_clear(pmdp); 1449 return 1; 1450 } 1451 1452 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1453 { 1454 pte_t *table; 1455 pmd_t pmd; 1456 1457 pmd = READ_ONCE(*pmdp); 1458 1459 if (!pmd_table(pmd)) { 1460 VM_WARN_ON(1); 1461 return 1; 1462 } 1463 1464 table = pte_offset_kernel(pmdp, addr); 1465 pmd_clear(pmdp); 1466 __flush_tlb_kernel_pgtable(addr); 1467 pte_free_kernel(NULL, table); 1468 return 1; 1469 } 1470 1471 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1472 { 1473 pmd_t *table; 1474 pmd_t *pmdp; 1475 pud_t pud; 1476 unsigned long next, end; 1477 1478 pud = READ_ONCE(*pudp); 1479 1480 if (!pud_table(pud)) { 1481 VM_WARN_ON(1); 1482 return 1; 1483 } 1484 1485 table = pmd_offset(pudp, addr); 1486 pmdp = table; 1487 next = addr; 1488 end = addr + PUD_SIZE; 1489 do { 1490 pmd_free_pte_page(pmdp, next); 1491 } while (pmdp++, next += PMD_SIZE, next != end); 1492 1493 pud_clear(pudp); 1494 __flush_tlb_kernel_pgtable(addr); 1495 pmd_free(NULL, table); 1496 return 1; 1497 } 1498 1499 #ifdef CONFIG_MEMORY_HOTPLUG 1500 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1501 { 1502 unsigned long end = start + size; 1503 1504 WARN_ON(pgdir != init_mm.pgd); 1505 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1506 1507 unmap_hotplug_range(start, end, false, NULL); 1508 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1509 } 1510 1511 struct range arch_get_mappable_range(void) 1512 { 1513 struct range mhp_range; 1514 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1515 u64 end_linear_pa = __pa(PAGE_END - 1); 1516 1517 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1518 /* 1519 * Check for a wrap, it is possible because of randomized linear 1520 * mapping the start physical address is actually bigger than 1521 * the end physical address. In this case set start to zero 1522 * because [0, end_linear_pa] range must still be able to cover 1523 * all addressable physical addresses. 1524 */ 1525 if (start_linear_pa > end_linear_pa) 1526 start_linear_pa = 0; 1527 } 1528 1529 WARN_ON(start_linear_pa > end_linear_pa); 1530 1531 /* 1532 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1533 * accommodating both its ends but excluding PAGE_END. Max physical 1534 * range which can be mapped inside this linear mapping range, must 1535 * also be derived from its end points. 1536 */ 1537 mhp_range.start = start_linear_pa; 1538 mhp_range.end = end_linear_pa; 1539 1540 return mhp_range; 1541 } 1542 1543 int arch_add_memory(int nid, u64 start, u64 size, 1544 struct mhp_params *params) 1545 { 1546 int ret, flags = NO_EXEC_MAPPINGS; 1547 1548 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1549 1550 /* 1551 * KFENCE requires linear map to be mapped at page granularity, so that 1552 * it is possible to protect/unprotect single pages in the KFENCE pool. 1553 */ 1554 if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) 1555 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1556 1557 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1558 size, params->pgprot, __pgd_pgtable_alloc, 1559 flags); 1560 1561 memblock_clear_nomap(start, size); 1562 1563 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1564 params); 1565 if (ret) 1566 __remove_pgd_mapping(swapper_pg_dir, 1567 __phys_to_virt(start), size); 1568 else { 1569 max_pfn = PFN_UP(start + size); 1570 max_low_pfn = max_pfn; 1571 } 1572 1573 return ret; 1574 } 1575 1576 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1577 { 1578 unsigned long start_pfn = start >> PAGE_SHIFT; 1579 unsigned long nr_pages = size >> PAGE_SHIFT; 1580 1581 __remove_pages(start_pfn, nr_pages, altmap); 1582 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1583 } 1584 1585 /* 1586 * This memory hotplug notifier helps prevent boot memory from being 1587 * inadvertently removed as it blocks pfn range offlining process in 1588 * __offline_pages(). Hence this prevents both offlining as well as 1589 * removal process for boot memory which is initially always online. 1590 * In future if and when boot memory could be removed, this notifier 1591 * should be dropped and free_hotplug_page_range() should handle any 1592 * reserved pages allocated during boot. 1593 */ 1594 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1595 unsigned long action, void *data) 1596 { 1597 struct mem_section *ms; 1598 struct memory_notify *arg = data; 1599 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1600 unsigned long pfn = arg->start_pfn; 1601 1602 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1603 return NOTIFY_OK; 1604 1605 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1606 unsigned long start = PFN_PHYS(pfn); 1607 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1608 1609 ms = __pfn_to_section(pfn); 1610 if (!early_section(ms)) 1611 continue; 1612 1613 if (action == MEM_GOING_OFFLINE) { 1614 /* 1615 * Boot memory removal is not supported. Prevent 1616 * it via blocking any attempted offline request 1617 * for the boot memory and just report it. 1618 */ 1619 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1620 return NOTIFY_BAD; 1621 } else if (action == MEM_OFFLINE) { 1622 /* 1623 * This should have never happened. Boot memory 1624 * offlining should have been prevented by this 1625 * very notifier. Probably some memory removal 1626 * procedure might have changed which would then 1627 * require further debug. 1628 */ 1629 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1630 1631 /* 1632 * Core memory hotplug does not process a return 1633 * code from the notifier for MEM_OFFLINE events. 1634 * The error condition has been reported. Return 1635 * from here as if ignored. 1636 */ 1637 return NOTIFY_DONE; 1638 } 1639 } 1640 return NOTIFY_OK; 1641 } 1642 1643 static struct notifier_block prevent_bootmem_remove_nb = { 1644 .notifier_call = prevent_bootmem_remove_notifier, 1645 }; 1646 1647 /* 1648 * This ensures that boot memory sections on the platform are online 1649 * from early boot. Memory sections could not be prevented from being 1650 * offlined, unless for some reason they are not online to begin with. 1651 * This helps validate the basic assumption on which the above memory 1652 * event notifier works to prevent boot memory section offlining and 1653 * its possible removal. 1654 */ 1655 static void validate_bootmem_online(void) 1656 { 1657 phys_addr_t start, end, addr; 1658 struct mem_section *ms; 1659 u64 i; 1660 1661 /* 1662 * Scanning across all memblock might be expensive 1663 * on some big memory systems. Hence enable this 1664 * validation only with DEBUG_VM. 1665 */ 1666 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1667 return; 1668 1669 for_each_mem_range(i, &start, &end) { 1670 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1671 ms = __pfn_to_section(PHYS_PFN(addr)); 1672 1673 /* 1674 * All memory ranges in the system at this point 1675 * should have been marked as early sections. 1676 */ 1677 WARN_ON(!early_section(ms)); 1678 1679 /* 1680 * Memory notifier mechanism here to prevent boot 1681 * memory offlining depends on the fact that each 1682 * early section memory on the system is initially 1683 * online. Otherwise a given memory section which 1684 * is already offline will be overlooked and can 1685 * be removed completely. Call out such sections. 1686 */ 1687 if (!online_section(ms)) 1688 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1689 addr, addr + (1UL << PA_SECTION_SHIFT)); 1690 } 1691 } 1692 } 1693 1694 static int __init prevent_bootmem_remove_init(void) 1695 { 1696 int ret = 0; 1697 1698 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1699 return ret; 1700 1701 validate_bootmem_online(); 1702 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1703 if (ret) 1704 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1705 1706 return ret; 1707 } 1708 early_initcall(prevent_bootmem_remove_init); 1709 #endif 1710