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 static int __init parse_rodata(char *arg) 646 { 647 int ret = strtobool(arg, &rodata_enabled); 648 if (!ret) { 649 rodata_full = false; 650 return 0; 651 } 652 653 /* permit 'full' in addition to boolean options */ 654 if (strcmp(arg, "full")) 655 return -EINVAL; 656 657 rodata_enabled = true; 658 rodata_full = true; 659 return 0; 660 } 661 early_param("rodata", parse_rodata); 662 663 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 664 static int __init map_entry_trampoline(void) 665 { 666 int i; 667 668 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 669 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 670 671 /* The trampoline is always mapped and can therefore be global */ 672 pgprot_val(prot) &= ~PTE_NG; 673 674 /* Map only the text into the trampoline page table */ 675 memset(tramp_pg_dir, 0, PGD_SIZE); 676 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 677 entry_tramp_text_size(), prot, 678 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 679 680 /* Map both the text and data into the kernel page table */ 681 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 682 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 683 pa_start + i * PAGE_SIZE, prot); 684 685 if (IS_ENABLED(CONFIG_RELOCATABLE)) 686 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 687 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 688 689 return 0; 690 } 691 core_initcall(map_entry_trampoline); 692 #endif 693 694 /* 695 * Open coded check for BTI, only for use to determine configuration 696 * for early mappings for before the cpufeature code has run. 697 */ 698 static bool arm64_early_this_cpu_has_bti(void) 699 { 700 u64 pfr1; 701 702 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 703 return false; 704 705 pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1); 706 return cpuid_feature_extract_unsigned_field(pfr1, 707 ID_AA64PFR1_BT_SHIFT); 708 } 709 710 /* 711 * Create fine-grained mappings for the kernel. 712 */ 713 static void __init map_kernel(pgd_t *pgdp) 714 { 715 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 716 vmlinux_initdata, vmlinux_data; 717 718 /* 719 * External debuggers may need to write directly to the text 720 * mapping to install SW breakpoints. Allow this (only) when 721 * explicitly requested with rodata=off. 722 */ 723 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 724 725 /* 726 * If we have a CPU that supports BTI and a kernel built for 727 * BTI then mark the kernel executable text as guarded pages 728 * now so we don't have to rewrite the page tables later. 729 */ 730 if (arm64_early_this_cpu_has_bti()) 731 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 732 733 /* 734 * Only rodata will be remapped with different permissions later on, 735 * all other segments are allowed to use contiguous mappings. 736 */ 737 map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0, 738 VM_NO_GUARD); 739 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 740 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 741 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 742 &vmlinux_inittext, 0, VM_NO_GUARD); 743 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 744 &vmlinux_initdata, 0, VM_NO_GUARD); 745 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 746 747 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { 748 /* 749 * The fixmap falls in a separate pgd to the kernel, and doesn't 750 * live in the carveout for the swapper_pg_dir. We can simply 751 * re-use the existing dir for the fixmap. 752 */ 753 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), 754 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 755 } else if (CONFIG_PGTABLE_LEVELS > 3) { 756 pgd_t *bm_pgdp; 757 p4d_t *bm_p4dp; 758 pud_t *bm_pudp; 759 /* 760 * The fixmap shares its top level pgd entry with the kernel 761 * mapping. This can really only occur when we are running 762 * with 16k/4 levels, so we can simply reuse the pud level 763 * entry instead. 764 */ 765 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 766 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); 767 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); 768 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); 769 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 770 pud_clear_fixmap(); 771 } else { 772 BUG(); 773 } 774 775 kasan_copy_shadow(pgdp); 776 } 777 778 static void __init create_idmap(void) 779 { 780 u64 start = __pa_symbol(__idmap_text_start); 781 u64 size = __pa_symbol(__idmap_text_end) - start; 782 pgd_t *pgd = idmap_pg_dir; 783 u64 pgd_phys; 784 785 /* check if we need an additional level of translation */ 786 if (VA_BITS < 48 && idmap_t0sz < (64 - VA_BITS_MIN)) { 787 pgd_phys = early_pgtable_alloc(PAGE_SHIFT); 788 set_pgd(&idmap_pg_dir[start >> VA_BITS], 789 __pgd(pgd_phys | P4D_TYPE_TABLE)); 790 pgd = __va(pgd_phys); 791 } 792 __create_pgd_mapping(pgd, start, start, size, PAGE_KERNEL_ROX, 793 early_pgtable_alloc, 0); 794 795 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) { 796 extern u32 __idmap_kpti_flag; 797 u64 pa = __pa_symbol(&__idmap_kpti_flag); 798 799 /* 800 * The KPTI G-to-nG conversion code needs a read-write mapping 801 * of its synchronization flag in the ID map. 802 */ 803 __create_pgd_mapping(pgd, pa, pa, sizeof(u32), PAGE_KERNEL, 804 early_pgtable_alloc, 0); 805 } 806 } 807 808 void __init paging_init(void) 809 { 810 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 811 extern pgd_t init_idmap_pg_dir[]; 812 813 idmap_t0sz = 63UL - __fls(__pa_symbol(_end) | GENMASK(VA_BITS_MIN - 1, 0)); 814 815 map_kernel(pgdp); 816 map_mem(pgdp); 817 818 pgd_clear_fixmap(); 819 820 cpu_replace_ttbr1(lm_alias(swapper_pg_dir), init_idmap_pg_dir); 821 init_mm.pgd = swapper_pg_dir; 822 823 memblock_phys_free(__pa_symbol(init_pg_dir), 824 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 825 826 memblock_allow_resize(); 827 828 create_idmap(); 829 } 830 831 /* 832 * Check whether a kernel address is valid (derived from arch/x86/). 833 */ 834 int kern_addr_valid(unsigned long addr) 835 { 836 pgd_t *pgdp; 837 p4d_t *p4dp; 838 pud_t *pudp, pud; 839 pmd_t *pmdp, pmd; 840 pte_t *ptep, pte; 841 842 addr = arch_kasan_reset_tag(addr); 843 if ((((long)addr) >> VA_BITS) != -1UL) 844 return 0; 845 846 pgdp = pgd_offset_k(addr); 847 if (pgd_none(READ_ONCE(*pgdp))) 848 return 0; 849 850 p4dp = p4d_offset(pgdp, addr); 851 if (p4d_none(READ_ONCE(*p4dp))) 852 return 0; 853 854 pudp = pud_offset(p4dp, addr); 855 pud = READ_ONCE(*pudp); 856 if (pud_none(pud)) 857 return 0; 858 859 if (pud_sect(pud)) 860 return pfn_valid(pud_pfn(pud)); 861 862 pmdp = pmd_offset(pudp, addr); 863 pmd = READ_ONCE(*pmdp); 864 if (pmd_none(pmd)) 865 return 0; 866 867 if (pmd_sect(pmd)) 868 return pfn_valid(pmd_pfn(pmd)); 869 870 ptep = pte_offset_kernel(pmdp, addr); 871 pte = READ_ONCE(*ptep); 872 if (pte_none(pte)) 873 return 0; 874 875 return pfn_valid(pte_pfn(pte)); 876 } 877 878 #ifdef CONFIG_MEMORY_HOTPLUG 879 static void free_hotplug_page_range(struct page *page, size_t size, 880 struct vmem_altmap *altmap) 881 { 882 if (altmap) { 883 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 884 } else { 885 WARN_ON(PageReserved(page)); 886 free_pages((unsigned long)page_address(page), get_order(size)); 887 } 888 } 889 890 static void free_hotplug_pgtable_page(struct page *page) 891 { 892 free_hotplug_page_range(page, PAGE_SIZE, NULL); 893 } 894 895 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 896 unsigned long floor, unsigned long ceiling, 897 unsigned long mask) 898 { 899 start &= mask; 900 if (start < floor) 901 return false; 902 903 if (ceiling) { 904 ceiling &= mask; 905 if (!ceiling) 906 return false; 907 } 908 909 if (end - 1 > ceiling - 1) 910 return false; 911 return true; 912 } 913 914 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 915 unsigned long end, bool free_mapped, 916 struct vmem_altmap *altmap) 917 { 918 pte_t *ptep, pte; 919 920 do { 921 ptep = pte_offset_kernel(pmdp, addr); 922 pte = READ_ONCE(*ptep); 923 if (pte_none(pte)) 924 continue; 925 926 WARN_ON(!pte_present(pte)); 927 pte_clear(&init_mm, addr, ptep); 928 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 929 if (free_mapped) 930 free_hotplug_page_range(pte_page(pte), 931 PAGE_SIZE, altmap); 932 } while (addr += PAGE_SIZE, addr < end); 933 } 934 935 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 936 unsigned long end, bool free_mapped, 937 struct vmem_altmap *altmap) 938 { 939 unsigned long next; 940 pmd_t *pmdp, pmd; 941 942 do { 943 next = pmd_addr_end(addr, end); 944 pmdp = pmd_offset(pudp, addr); 945 pmd = READ_ONCE(*pmdp); 946 if (pmd_none(pmd)) 947 continue; 948 949 WARN_ON(!pmd_present(pmd)); 950 if (pmd_sect(pmd)) { 951 pmd_clear(pmdp); 952 953 /* 954 * One TLBI should be sufficient here as the PMD_SIZE 955 * range is mapped with a single block entry. 956 */ 957 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 958 if (free_mapped) 959 free_hotplug_page_range(pmd_page(pmd), 960 PMD_SIZE, altmap); 961 continue; 962 } 963 WARN_ON(!pmd_table(pmd)); 964 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 965 } while (addr = next, addr < end); 966 } 967 968 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 969 unsigned long end, bool free_mapped, 970 struct vmem_altmap *altmap) 971 { 972 unsigned long next; 973 pud_t *pudp, pud; 974 975 do { 976 next = pud_addr_end(addr, end); 977 pudp = pud_offset(p4dp, addr); 978 pud = READ_ONCE(*pudp); 979 if (pud_none(pud)) 980 continue; 981 982 WARN_ON(!pud_present(pud)); 983 if (pud_sect(pud)) { 984 pud_clear(pudp); 985 986 /* 987 * One TLBI should be sufficient here as the PUD_SIZE 988 * range is mapped with a single block entry. 989 */ 990 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 991 if (free_mapped) 992 free_hotplug_page_range(pud_page(pud), 993 PUD_SIZE, altmap); 994 continue; 995 } 996 WARN_ON(!pud_table(pud)); 997 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 998 } while (addr = next, addr < end); 999 } 1000 1001 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 1002 unsigned long end, bool free_mapped, 1003 struct vmem_altmap *altmap) 1004 { 1005 unsigned long next; 1006 p4d_t *p4dp, p4d; 1007 1008 do { 1009 next = p4d_addr_end(addr, end); 1010 p4dp = p4d_offset(pgdp, addr); 1011 p4d = READ_ONCE(*p4dp); 1012 if (p4d_none(p4d)) 1013 continue; 1014 1015 WARN_ON(!p4d_present(p4d)); 1016 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 1017 } while (addr = next, addr < end); 1018 } 1019 1020 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 1021 bool free_mapped, struct vmem_altmap *altmap) 1022 { 1023 unsigned long next; 1024 pgd_t *pgdp, pgd; 1025 1026 /* 1027 * altmap can only be used as vmemmap mapping backing memory. 1028 * In case the backing memory itself is not being freed, then 1029 * altmap is irrelevant. Warn about this inconsistency when 1030 * encountered. 1031 */ 1032 WARN_ON(!free_mapped && altmap); 1033 1034 do { 1035 next = pgd_addr_end(addr, end); 1036 pgdp = pgd_offset_k(addr); 1037 pgd = READ_ONCE(*pgdp); 1038 if (pgd_none(pgd)) 1039 continue; 1040 1041 WARN_ON(!pgd_present(pgd)); 1042 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 1043 } while (addr = next, addr < end); 1044 } 1045 1046 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 1047 unsigned long end, unsigned long floor, 1048 unsigned long ceiling) 1049 { 1050 pte_t *ptep, pte; 1051 unsigned long i, start = addr; 1052 1053 do { 1054 ptep = pte_offset_kernel(pmdp, addr); 1055 pte = READ_ONCE(*ptep); 1056 1057 /* 1058 * This is just a sanity check here which verifies that 1059 * pte clearing has been done by earlier unmap loops. 1060 */ 1061 WARN_ON(!pte_none(pte)); 1062 } while (addr += PAGE_SIZE, addr < end); 1063 1064 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1065 return; 1066 1067 /* 1068 * Check whether we can free the pte page if the rest of the 1069 * entries are empty. Overlap with other regions have been 1070 * handled by the floor/ceiling check. 1071 */ 1072 ptep = pte_offset_kernel(pmdp, 0UL); 1073 for (i = 0; i < PTRS_PER_PTE; i++) { 1074 if (!pte_none(READ_ONCE(ptep[i]))) 1075 return; 1076 } 1077 1078 pmd_clear(pmdp); 1079 __flush_tlb_kernel_pgtable(start); 1080 free_hotplug_pgtable_page(virt_to_page(ptep)); 1081 } 1082 1083 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1084 unsigned long end, unsigned long floor, 1085 unsigned long ceiling) 1086 { 1087 pmd_t *pmdp, pmd; 1088 unsigned long i, next, start = addr; 1089 1090 do { 1091 next = pmd_addr_end(addr, end); 1092 pmdp = pmd_offset(pudp, addr); 1093 pmd = READ_ONCE(*pmdp); 1094 if (pmd_none(pmd)) 1095 continue; 1096 1097 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1098 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1099 } while (addr = next, addr < end); 1100 1101 if (CONFIG_PGTABLE_LEVELS <= 2) 1102 return; 1103 1104 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1105 return; 1106 1107 /* 1108 * Check whether we can free the pmd page if the rest of the 1109 * entries are empty. Overlap with other regions have been 1110 * handled by the floor/ceiling check. 1111 */ 1112 pmdp = pmd_offset(pudp, 0UL); 1113 for (i = 0; i < PTRS_PER_PMD; i++) { 1114 if (!pmd_none(READ_ONCE(pmdp[i]))) 1115 return; 1116 } 1117 1118 pud_clear(pudp); 1119 __flush_tlb_kernel_pgtable(start); 1120 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1121 } 1122 1123 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1124 unsigned long end, unsigned long floor, 1125 unsigned long ceiling) 1126 { 1127 pud_t *pudp, pud; 1128 unsigned long i, next, start = addr; 1129 1130 do { 1131 next = pud_addr_end(addr, end); 1132 pudp = pud_offset(p4dp, addr); 1133 pud = READ_ONCE(*pudp); 1134 if (pud_none(pud)) 1135 continue; 1136 1137 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1138 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1139 } while (addr = next, addr < end); 1140 1141 if (CONFIG_PGTABLE_LEVELS <= 3) 1142 return; 1143 1144 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1145 return; 1146 1147 /* 1148 * Check whether we can free the pud page if the rest of the 1149 * entries are empty. Overlap with other regions have been 1150 * handled by the floor/ceiling check. 1151 */ 1152 pudp = pud_offset(p4dp, 0UL); 1153 for (i = 0; i < PTRS_PER_PUD; i++) { 1154 if (!pud_none(READ_ONCE(pudp[i]))) 1155 return; 1156 } 1157 1158 p4d_clear(p4dp); 1159 __flush_tlb_kernel_pgtable(start); 1160 free_hotplug_pgtable_page(virt_to_page(pudp)); 1161 } 1162 1163 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1164 unsigned long end, unsigned long floor, 1165 unsigned long ceiling) 1166 { 1167 unsigned long next; 1168 p4d_t *p4dp, p4d; 1169 1170 do { 1171 next = p4d_addr_end(addr, end); 1172 p4dp = p4d_offset(pgdp, addr); 1173 p4d = READ_ONCE(*p4dp); 1174 if (p4d_none(p4d)) 1175 continue; 1176 1177 WARN_ON(!p4d_present(p4d)); 1178 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1179 } while (addr = next, addr < end); 1180 } 1181 1182 static void free_empty_tables(unsigned long addr, unsigned long end, 1183 unsigned long floor, unsigned long ceiling) 1184 { 1185 unsigned long next; 1186 pgd_t *pgdp, pgd; 1187 1188 do { 1189 next = pgd_addr_end(addr, end); 1190 pgdp = pgd_offset_k(addr); 1191 pgd = READ_ONCE(*pgdp); 1192 if (pgd_none(pgd)) 1193 continue; 1194 1195 WARN_ON(!pgd_present(pgd)); 1196 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1197 } while (addr = next, addr < end); 1198 } 1199 #endif 1200 1201 #if !ARM64_KERNEL_USES_PMD_MAPS 1202 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1203 struct vmem_altmap *altmap) 1204 { 1205 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1206 return vmemmap_populate_basepages(start, end, node, altmap); 1207 } 1208 #else /* !ARM64_KERNEL_USES_PMD_MAPS */ 1209 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1210 struct vmem_altmap *altmap) 1211 { 1212 unsigned long addr = start; 1213 unsigned long next; 1214 pgd_t *pgdp; 1215 p4d_t *p4dp; 1216 pud_t *pudp; 1217 pmd_t *pmdp; 1218 1219 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1220 do { 1221 next = pmd_addr_end(addr, end); 1222 1223 pgdp = vmemmap_pgd_populate(addr, node); 1224 if (!pgdp) 1225 return -ENOMEM; 1226 1227 p4dp = vmemmap_p4d_populate(pgdp, addr, node); 1228 if (!p4dp) 1229 return -ENOMEM; 1230 1231 pudp = vmemmap_pud_populate(p4dp, addr, node); 1232 if (!pudp) 1233 return -ENOMEM; 1234 1235 pmdp = pmd_offset(pudp, addr); 1236 if (pmd_none(READ_ONCE(*pmdp))) { 1237 void *p = NULL; 1238 1239 p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap); 1240 if (!p) { 1241 if (vmemmap_populate_basepages(addr, next, node, altmap)) 1242 return -ENOMEM; 1243 continue; 1244 } 1245 1246 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1247 } else 1248 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1249 } while (addr = next, addr != end); 1250 1251 return 0; 1252 } 1253 #endif /* !ARM64_KERNEL_USES_PMD_MAPS */ 1254 1255 #ifdef CONFIG_MEMORY_HOTPLUG 1256 void vmemmap_free(unsigned long start, unsigned long end, 1257 struct vmem_altmap *altmap) 1258 { 1259 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1260 1261 unmap_hotplug_range(start, end, true, altmap); 1262 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1263 } 1264 #endif /* CONFIG_MEMORY_HOTPLUG */ 1265 1266 static inline pud_t *fixmap_pud(unsigned long addr) 1267 { 1268 pgd_t *pgdp = pgd_offset_k(addr); 1269 p4d_t *p4dp = p4d_offset(pgdp, addr); 1270 p4d_t p4d = READ_ONCE(*p4dp); 1271 1272 BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); 1273 1274 return pud_offset_kimg(p4dp, addr); 1275 } 1276 1277 static inline pmd_t *fixmap_pmd(unsigned long addr) 1278 { 1279 pud_t *pudp = fixmap_pud(addr); 1280 pud_t pud = READ_ONCE(*pudp); 1281 1282 BUG_ON(pud_none(pud) || pud_bad(pud)); 1283 1284 return pmd_offset_kimg(pudp, addr); 1285 } 1286 1287 static inline pte_t *fixmap_pte(unsigned long addr) 1288 { 1289 return &bm_pte[pte_index(addr)]; 1290 } 1291 1292 /* 1293 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 1294 * directly on kernel symbols (bm_p*d). This function is called too early to use 1295 * lm_alias so __p*d_populate functions must be used to populate with the 1296 * physical address from __pa_symbol. 1297 */ 1298 void __init early_fixmap_init(void) 1299 { 1300 pgd_t *pgdp; 1301 p4d_t *p4dp, p4d; 1302 pud_t *pudp; 1303 pmd_t *pmdp; 1304 unsigned long addr = FIXADDR_START; 1305 1306 pgdp = pgd_offset_k(addr); 1307 p4dp = p4d_offset(pgdp, addr); 1308 p4d = READ_ONCE(*p4dp); 1309 if (CONFIG_PGTABLE_LEVELS > 3 && 1310 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { 1311 /* 1312 * We only end up here if the kernel mapping and the fixmap 1313 * share the top level pgd entry, which should only happen on 1314 * 16k/4 levels configurations. 1315 */ 1316 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 1317 pudp = pud_offset_kimg(p4dp, addr); 1318 } else { 1319 if (p4d_none(p4d)) 1320 __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); 1321 pudp = fixmap_pud(addr); 1322 } 1323 if (pud_none(READ_ONCE(*pudp))) 1324 __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); 1325 pmdp = fixmap_pmd(addr); 1326 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 1327 1328 /* 1329 * The boot-ioremap range spans multiple pmds, for which 1330 * we are not prepared: 1331 */ 1332 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 1333 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 1334 1335 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 1336 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 1337 WARN_ON(1); 1338 pr_warn("pmdp %p != %p, %p\n", 1339 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 1340 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 1341 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 1342 fix_to_virt(FIX_BTMAP_BEGIN)); 1343 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 1344 fix_to_virt(FIX_BTMAP_END)); 1345 1346 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 1347 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 1348 } 1349 } 1350 1351 /* 1352 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 1353 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 1354 */ 1355 void __set_fixmap(enum fixed_addresses idx, 1356 phys_addr_t phys, pgprot_t flags) 1357 { 1358 unsigned long addr = __fix_to_virt(idx); 1359 pte_t *ptep; 1360 1361 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 1362 1363 ptep = fixmap_pte(addr); 1364 1365 if (pgprot_val(flags)) { 1366 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 1367 } else { 1368 pte_clear(&init_mm, addr, ptep); 1369 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 1370 } 1371 } 1372 1373 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 1374 { 1375 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 1376 int offset; 1377 void *dt_virt; 1378 1379 /* 1380 * Check whether the physical FDT address is set and meets the minimum 1381 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 1382 * at least 8 bytes so that we can always access the magic and size 1383 * fields of the FDT header after mapping the first chunk, double check 1384 * here if that is indeed the case. 1385 */ 1386 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 1387 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 1388 return NULL; 1389 1390 /* 1391 * Make sure that the FDT region can be mapped without the need to 1392 * allocate additional translation table pages, so that it is safe 1393 * to call create_mapping_noalloc() this early. 1394 * 1395 * On 64k pages, the FDT will be mapped using PTEs, so we need to 1396 * be in the same PMD as the rest of the fixmap. 1397 * On 4k pages, we'll use section mappings for the FDT so we only 1398 * have to be in the same PUD. 1399 */ 1400 BUILD_BUG_ON(dt_virt_base % SZ_2M); 1401 1402 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 1403 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 1404 1405 offset = dt_phys % SWAPPER_BLOCK_SIZE; 1406 dt_virt = (void *)dt_virt_base + offset; 1407 1408 /* map the first chunk so we can read the size from the header */ 1409 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 1410 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 1411 1412 if (fdt_magic(dt_virt) != FDT_MAGIC) 1413 return NULL; 1414 1415 *size = fdt_totalsize(dt_virt); 1416 if (*size > MAX_FDT_SIZE) 1417 return NULL; 1418 1419 if (offset + *size > SWAPPER_BLOCK_SIZE) 1420 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 1421 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 1422 1423 return dt_virt; 1424 } 1425 1426 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1427 { 1428 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1429 1430 /* Only allow permission changes for now */ 1431 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1432 pud_val(new_pud))) 1433 return 0; 1434 1435 VM_BUG_ON(phys & ~PUD_MASK); 1436 set_pud(pudp, new_pud); 1437 return 1; 1438 } 1439 1440 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1441 { 1442 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1443 1444 /* Only allow permission changes for now */ 1445 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1446 pmd_val(new_pmd))) 1447 return 0; 1448 1449 VM_BUG_ON(phys & ~PMD_MASK); 1450 set_pmd(pmdp, new_pmd); 1451 return 1; 1452 } 1453 1454 int pud_clear_huge(pud_t *pudp) 1455 { 1456 if (!pud_sect(READ_ONCE(*pudp))) 1457 return 0; 1458 pud_clear(pudp); 1459 return 1; 1460 } 1461 1462 int pmd_clear_huge(pmd_t *pmdp) 1463 { 1464 if (!pmd_sect(READ_ONCE(*pmdp))) 1465 return 0; 1466 pmd_clear(pmdp); 1467 return 1; 1468 } 1469 1470 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1471 { 1472 pte_t *table; 1473 pmd_t pmd; 1474 1475 pmd = READ_ONCE(*pmdp); 1476 1477 if (!pmd_table(pmd)) { 1478 VM_WARN_ON(1); 1479 return 1; 1480 } 1481 1482 table = pte_offset_kernel(pmdp, addr); 1483 pmd_clear(pmdp); 1484 __flush_tlb_kernel_pgtable(addr); 1485 pte_free_kernel(NULL, table); 1486 return 1; 1487 } 1488 1489 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1490 { 1491 pmd_t *table; 1492 pmd_t *pmdp; 1493 pud_t pud; 1494 unsigned long next, end; 1495 1496 pud = READ_ONCE(*pudp); 1497 1498 if (!pud_table(pud)) { 1499 VM_WARN_ON(1); 1500 return 1; 1501 } 1502 1503 table = pmd_offset(pudp, addr); 1504 pmdp = table; 1505 next = addr; 1506 end = addr + PUD_SIZE; 1507 do { 1508 pmd_free_pte_page(pmdp, next); 1509 } while (pmdp++, next += PMD_SIZE, next != end); 1510 1511 pud_clear(pudp); 1512 __flush_tlb_kernel_pgtable(addr); 1513 pmd_free(NULL, table); 1514 return 1; 1515 } 1516 1517 #ifdef CONFIG_MEMORY_HOTPLUG 1518 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1519 { 1520 unsigned long end = start + size; 1521 1522 WARN_ON(pgdir != init_mm.pgd); 1523 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1524 1525 unmap_hotplug_range(start, end, false, NULL); 1526 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1527 } 1528 1529 struct range arch_get_mappable_range(void) 1530 { 1531 struct range mhp_range; 1532 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1533 u64 end_linear_pa = __pa(PAGE_END - 1); 1534 1535 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1536 /* 1537 * Check for a wrap, it is possible because of randomized linear 1538 * mapping the start physical address is actually bigger than 1539 * the end physical address. In this case set start to zero 1540 * because [0, end_linear_pa] range must still be able to cover 1541 * all addressable physical addresses. 1542 */ 1543 if (start_linear_pa > end_linear_pa) 1544 start_linear_pa = 0; 1545 } 1546 1547 WARN_ON(start_linear_pa > end_linear_pa); 1548 1549 /* 1550 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1551 * accommodating both its ends but excluding PAGE_END. Max physical 1552 * range which can be mapped inside this linear mapping range, must 1553 * also be derived from its end points. 1554 */ 1555 mhp_range.start = start_linear_pa; 1556 mhp_range.end = end_linear_pa; 1557 1558 return mhp_range; 1559 } 1560 1561 int arch_add_memory(int nid, u64 start, u64 size, 1562 struct mhp_params *params) 1563 { 1564 int ret, flags = NO_EXEC_MAPPINGS; 1565 1566 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1567 1568 /* 1569 * KFENCE requires linear map to be mapped at page granularity, so that 1570 * it is possible to protect/unprotect single pages in the KFENCE pool. 1571 */ 1572 if (can_set_direct_map() || IS_ENABLED(CONFIG_KFENCE)) 1573 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1574 1575 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1576 size, params->pgprot, __pgd_pgtable_alloc, 1577 flags); 1578 1579 memblock_clear_nomap(start, size); 1580 1581 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1582 params); 1583 if (ret) 1584 __remove_pgd_mapping(swapper_pg_dir, 1585 __phys_to_virt(start), size); 1586 else { 1587 max_pfn = PFN_UP(start + size); 1588 max_low_pfn = max_pfn; 1589 } 1590 1591 return ret; 1592 } 1593 1594 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1595 { 1596 unsigned long start_pfn = start >> PAGE_SHIFT; 1597 unsigned long nr_pages = size >> PAGE_SHIFT; 1598 1599 __remove_pages(start_pfn, nr_pages, altmap); 1600 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1601 } 1602 1603 /* 1604 * This memory hotplug notifier helps prevent boot memory from being 1605 * inadvertently removed as it blocks pfn range offlining process in 1606 * __offline_pages(). Hence this prevents both offlining as well as 1607 * removal process for boot memory which is initially always online. 1608 * In future if and when boot memory could be removed, this notifier 1609 * should be dropped and free_hotplug_page_range() should handle any 1610 * reserved pages allocated during boot. 1611 */ 1612 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1613 unsigned long action, void *data) 1614 { 1615 struct mem_section *ms; 1616 struct memory_notify *arg = data; 1617 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1618 unsigned long pfn = arg->start_pfn; 1619 1620 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1621 return NOTIFY_OK; 1622 1623 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1624 unsigned long start = PFN_PHYS(pfn); 1625 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1626 1627 ms = __pfn_to_section(pfn); 1628 if (!early_section(ms)) 1629 continue; 1630 1631 if (action == MEM_GOING_OFFLINE) { 1632 /* 1633 * Boot memory removal is not supported. Prevent 1634 * it via blocking any attempted offline request 1635 * for the boot memory and just report it. 1636 */ 1637 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1638 return NOTIFY_BAD; 1639 } else if (action == MEM_OFFLINE) { 1640 /* 1641 * This should have never happened. Boot memory 1642 * offlining should have been prevented by this 1643 * very notifier. Probably some memory removal 1644 * procedure might have changed which would then 1645 * require further debug. 1646 */ 1647 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1648 1649 /* 1650 * Core memory hotplug does not process a return 1651 * code from the notifier for MEM_OFFLINE events. 1652 * The error condition has been reported. Return 1653 * from here as if ignored. 1654 */ 1655 return NOTIFY_DONE; 1656 } 1657 } 1658 return NOTIFY_OK; 1659 } 1660 1661 static struct notifier_block prevent_bootmem_remove_nb = { 1662 .notifier_call = prevent_bootmem_remove_notifier, 1663 }; 1664 1665 /* 1666 * This ensures that boot memory sections on the platform are online 1667 * from early boot. Memory sections could not be prevented from being 1668 * offlined, unless for some reason they are not online to begin with. 1669 * This helps validate the basic assumption on which the above memory 1670 * event notifier works to prevent boot memory section offlining and 1671 * its possible removal. 1672 */ 1673 static void validate_bootmem_online(void) 1674 { 1675 phys_addr_t start, end, addr; 1676 struct mem_section *ms; 1677 u64 i; 1678 1679 /* 1680 * Scanning across all memblock might be expensive 1681 * on some big memory systems. Hence enable this 1682 * validation only with DEBUG_VM. 1683 */ 1684 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1685 return; 1686 1687 for_each_mem_range(i, &start, &end) { 1688 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1689 ms = __pfn_to_section(PHYS_PFN(addr)); 1690 1691 /* 1692 * All memory ranges in the system at this point 1693 * should have been marked as early sections. 1694 */ 1695 WARN_ON(!early_section(ms)); 1696 1697 /* 1698 * Memory notifier mechanism here to prevent boot 1699 * memory offlining depends on the fact that each 1700 * early section memory on the system is initially 1701 * online. Otherwise a given memory section which 1702 * is already offline will be overlooked and can 1703 * be removed completely. Call out such sections. 1704 */ 1705 if (!online_section(ms)) 1706 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1707 addr, addr + (1UL << PA_SECTION_SHIFT)); 1708 } 1709 } 1710 } 1711 1712 static int __init prevent_bootmem_remove_init(void) 1713 { 1714 int ret = 0; 1715 1716 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1717 return ret; 1718 1719 validate_bootmem_online(); 1720 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1721 if (ret) 1722 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1723 1724 return ret; 1725 } 1726 early_initcall(prevent_bootmem_remove_init); 1727 #endif 1728