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 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 (!pte_valid(__pte(old)) || !pte_valid(__pte(new))) 146 return true; 147 148 /* A live entry's pfn should not change */ 149 if (pte_pfn(__pte(old)) != pte_pfn(__pte(new))) 150 return false; 151 152 /* live contiguous mappings may not be manipulated at all */ 153 if ((old | new) & PTE_CONT) 154 return false; 155 156 /* Transitioning from Non-Global to Global is unsafe */ 157 if (old & ~new & PTE_NG) 158 return false; 159 160 /* 161 * Changing the memory type between Normal and Normal-Tagged is safe 162 * since Tagged is considered a permission attribute from the 163 * mismatched attribute aliases perspective. 164 */ 165 if (((old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 166 (old & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED)) && 167 ((new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL) || 168 (new & PTE_ATTRINDX_MASK) == PTE_ATTRINDX(MT_NORMAL_TAGGED))) 169 mask |= PTE_ATTRINDX_MASK; 170 171 return ((old ^ new) & ~mask) == 0; 172 } 173 174 static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end, 175 phys_addr_t phys, pgprot_t prot) 176 { 177 pte_t *ptep; 178 179 ptep = pte_set_fixmap_offset(pmdp, addr); 180 do { 181 pte_t old_pte = READ_ONCE(*ptep); 182 183 set_pte(ptep, pfn_pte(__phys_to_pfn(phys), prot)); 184 185 /* 186 * After the PTE entry has been populated once, we 187 * only allow updates to the permission attributes. 188 */ 189 BUG_ON(!pgattr_change_is_safe(pte_val(old_pte), 190 READ_ONCE(pte_val(*ptep)))); 191 192 phys += PAGE_SIZE; 193 } while (ptep++, addr += PAGE_SIZE, addr != end); 194 195 pte_clear_fixmap(); 196 } 197 198 static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, 199 unsigned long end, phys_addr_t phys, 200 pgprot_t prot, 201 phys_addr_t (*pgtable_alloc)(int), 202 int flags) 203 { 204 unsigned long next; 205 pmd_t pmd = READ_ONCE(*pmdp); 206 207 BUG_ON(pmd_sect(pmd)); 208 if (pmd_none(pmd)) { 209 pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN; 210 phys_addr_t pte_phys; 211 212 if (flags & NO_EXEC_MAPPINGS) 213 pmdval |= PMD_TABLE_PXN; 214 BUG_ON(!pgtable_alloc); 215 pte_phys = pgtable_alloc(PAGE_SHIFT); 216 __pmd_populate(pmdp, pte_phys, pmdval); 217 pmd = READ_ONCE(*pmdp); 218 } 219 BUG_ON(pmd_bad(pmd)); 220 221 do { 222 pgprot_t __prot = prot; 223 224 next = pte_cont_addr_end(addr, end); 225 226 /* use a contiguous mapping if the range is suitably aligned */ 227 if ((((addr | next | phys) & ~CONT_PTE_MASK) == 0) && 228 (flags & NO_CONT_MAPPINGS) == 0) 229 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 230 231 init_pte(pmdp, addr, next, phys, __prot); 232 233 phys += next - addr; 234 } while (addr = next, addr != end); 235 } 236 237 static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end, 238 phys_addr_t phys, pgprot_t prot, 239 phys_addr_t (*pgtable_alloc)(int), int flags) 240 { 241 unsigned long next; 242 pmd_t *pmdp; 243 244 pmdp = pmd_set_fixmap_offset(pudp, addr); 245 do { 246 pmd_t old_pmd = READ_ONCE(*pmdp); 247 248 next = pmd_addr_end(addr, end); 249 250 /* try section mapping first */ 251 if (((addr | next | phys) & ~PMD_MASK) == 0 && 252 (flags & NO_BLOCK_MAPPINGS) == 0) { 253 pmd_set_huge(pmdp, phys, prot); 254 255 /* 256 * After the PMD entry has been populated once, we 257 * only allow updates to the permission attributes. 258 */ 259 BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd), 260 READ_ONCE(pmd_val(*pmdp)))); 261 } else { 262 alloc_init_cont_pte(pmdp, addr, next, phys, prot, 263 pgtable_alloc, flags); 264 265 BUG_ON(pmd_val(old_pmd) != 0 && 266 pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp))); 267 } 268 phys += next - addr; 269 } while (pmdp++, addr = next, addr != end); 270 271 pmd_clear_fixmap(); 272 } 273 274 static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, 275 unsigned long end, phys_addr_t phys, 276 pgprot_t prot, 277 phys_addr_t (*pgtable_alloc)(int), int flags) 278 { 279 unsigned long next; 280 pud_t pud = READ_ONCE(*pudp); 281 282 /* 283 * Check for initial section mappings in the pgd/pud. 284 */ 285 BUG_ON(pud_sect(pud)); 286 if (pud_none(pud)) { 287 pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN; 288 phys_addr_t pmd_phys; 289 290 if (flags & NO_EXEC_MAPPINGS) 291 pudval |= PUD_TABLE_PXN; 292 BUG_ON(!pgtable_alloc); 293 pmd_phys = pgtable_alloc(PMD_SHIFT); 294 __pud_populate(pudp, pmd_phys, pudval); 295 pud = READ_ONCE(*pudp); 296 } 297 BUG_ON(pud_bad(pud)); 298 299 do { 300 pgprot_t __prot = prot; 301 302 next = pmd_cont_addr_end(addr, end); 303 304 /* use a contiguous mapping if the range is suitably aligned */ 305 if ((((addr | next | phys) & ~CONT_PMD_MASK) == 0) && 306 (flags & NO_CONT_MAPPINGS) == 0) 307 __prot = __pgprot(pgprot_val(prot) | PTE_CONT); 308 309 init_pmd(pudp, addr, next, phys, __prot, pgtable_alloc, flags); 310 311 phys += next - addr; 312 } while (addr = next, addr != end); 313 } 314 315 static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, 316 phys_addr_t phys, pgprot_t prot, 317 phys_addr_t (*pgtable_alloc)(int), 318 int flags) 319 { 320 unsigned long next; 321 pud_t *pudp; 322 p4d_t *p4dp = p4d_offset(pgdp, addr); 323 p4d_t p4d = READ_ONCE(*p4dp); 324 325 if (p4d_none(p4d)) { 326 p4dval_t p4dval = P4D_TYPE_TABLE | P4D_TABLE_UXN; 327 phys_addr_t pud_phys; 328 329 if (flags & NO_EXEC_MAPPINGS) 330 p4dval |= P4D_TABLE_PXN; 331 BUG_ON(!pgtable_alloc); 332 pud_phys = pgtable_alloc(PUD_SHIFT); 333 __p4d_populate(p4dp, pud_phys, p4dval); 334 p4d = READ_ONCE(*p4dp); 335 } 336 BUG_ON(p4d_bad(p4d)); 337 338 pudp = pud_set_fixmap_offset(p4dp, addr); 339 do { 340 pud_t old_pud = READ_ONCE(*pudp); 341 342 next = pud_addr_end(addr, end); 343 344 /* 345 * For 4K granule only, attempt to put down a 1GB block 346 */ 347 if (pud_sect_supported() && 348 ((addr | next | phys) & ~PUD_MASK) == 0 && 349 (flags & NO_BLOCK_MAPPINGS) == 0) { 350 pud_set_huge(pudp, phys, prot); 351 352 /* 353 * After the PUD entry has been populated once, we 354 * only allow updates to the permission attributes. 355 */ 356 BUG_ON(!pgattr_change_is_safe(pud_val(old_pud), 357 READ_ONCE(pud_val(*pudp)))); 358 } else { 359 alloc_init_cont_pmd(pudp, addr, next, phys, prot, 360 pgtable_alloc, flags); 361 362 BUG_ON(pud_val(old_pud) != 0 && 363 pud_val(old_pud) != READ_ONCE(pud_val(*pudp))); 364 } 365 phys += next - addr; 366 } while (pudp++, addr = next, addr != end); 367 368 pud_clear_fixmap(); 369 } 370 371 static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, 372 unsigned long virt, phys_addr_t size, 373 pgprot_t prot, 374 phys_addr_t (*pgtable_alloc)(int), 375 int flags) 376 { 377 unsigned long addr, end, next; 378 pgd_t *pgdp = pgd_offset_pgd(pgdir, virt); 379 380 /* 381 * If the virtual and physical address don't have the same offset 382 * within a page, we cannot map the region as the caller expects. 383 */ 384 if (WARN_ON((phys ^ virt) & ~PAGE_MASK)) 385 return; 386 387 phys &= PAGE_MASK; 388 addr = virt & PAGE_MASK; 389 end = PAGE_ALIGN(virt + size); 390 391 do { 392 next = pgd_addr_end(addr, end); 393 alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc, 394 flags); 395 phys += next - addr; 396 } while (pgdp++, addr = next, addr != end); 397 } 398 399 static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys, 400 unsigned long virt, phys_addr_t size, 401 pgprot_t prot, 402 phys_addr_t (*pgtable_alloc)(int), 403 int flags) 404 { 405 mutex_lock(&fixmap_lock); 406 __create_pgd_mapping_locked(pgdir, phys, virt, size, prot, 407 pgtable_alloc, flags); 408 mutex_unlock(&fixmap_lock); 409 } 410 411 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 412 extern __alias(__create_pgd_mapping_locked) 413 void create_kpti_ng_temp_pgd(pgd_t *pgdir, phys_addr_t phys, unsigned long virt, 414 phys_addr_t size, pgprot_t prot, 415 phys_addr_t (*pgtable_alloc)(int), int flags); 416 #endif 417 418 static phys_addr_t __pgd_pgtable_alloc(int shift) 419 { 420 void *ptr = (void *)__get_free_page(GFP_PGTABLE_KERNEL); 421 BUG_ON(!ptr); 422 423 /* Ensure the zeroed page is visible to the page table walker */ 424 dsb(ishst); 425 return __pa(ptr); 426 } 427 428 static phys_addr_t pgd_pgtable_alloc(int shift) 429 { 430 phys_addr_t pa = __pgd_pgtable_alloc(shift); 431 432 /* 433 * Call proper page table ctor in case later we need to 434 * call core mm functions like apply_to_page_range() on 435 * this pre-allocated page table. 436 * 437 * We don't select ARCH_ENABLE_SPLIT_PMD_PTLOCK if pmd is 438 * folded, and if so pgtable_pmd_page_ctor() becomes nop. 439 */ 440 if (shift == PAGE_SHIFT) 441 BUG_ON(!pgtable_pte_page_ctor(phys_to_page(pa))); 442 else if (shift == PMD_SHIFT) 443 BUG_ON(!pgtable_pmd_page_ctor(phys_to_page(pa))); 444 445 return pa; 446 } 447 448 /* 449 * This function can only be used to modify existing table entries, 450 * without allocating new levels of table. Note that this permits the 451 * creation of new section or page entries. 452 */ 453 static void __init create_mapping_noalloc(phys_addr_t phys, unsigned long virt, 454 phys_addr_t size, pgprot_t prot) 455 { 456 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 457 pr_warn("BUG: not creating mapping for %pa at 0x%016lx - outside kernel range\n", 458 &phys, virt); 459 return; 460 } 461 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 462 NO_CONT_MAPPINGS); 463 } 464 465 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, 466 unsigned long virt, phys_addr_t size, 467 pgprot_t prot, bool page_mappings_only) 468 { 469 int flags = 0; 470 471 BUG_ON(mm == &init_mm); 472 473 if (page_mappings_only) 474 flags = NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 475 476 __create_pgd_mapping(mm->pgd, phys, virt, size, prot, 477 pgd_pgtable_alloc, flags); 478 } 479 480 static void update_mapping_prot(phys_addr_t phys, unsigned long virt, 481 phys_addr_t size, pgprot_t prot) 482 { 483 if ((virt >= PAGE_END) && (virt < VMALLOC_START)) { 484 pr_warn("BUG: not updating mapping for %pa at 0x%016lx - outside kernel range\n", 485 &phys, virt); 486 return; 487 } 488 489 __create_pgd_mapping(init_mm.pgd, phys, virt, size, prot, NULL, 490 NO_CONT_MAPPINGS); 491 492 /* flush the TLBs after updating live kernel mappings */ 493 flush_tlb_kernel_range(virt, virt + size); 494 } 495 496 static void __init __map_memblock(pgd_t *pgdp, phys_addr_t start, 497 phys_addr_t end, pgprot_t prot, int flags) 498 { 499 __create_pgd_mapping(pgdp, start, __phys_to_virt(start), end - start, 500 prot, early_pgtable_alloc, flags); 501 } 502 503 void __init mark_linear_text_alias_ro(void) 504 { 505 /* 506 * Remove the write permissions from the linear alias of .text/.rodata 507 */ 508 update_mapping_prot(__pa_symbol(_stext), (unsigned long)lm_alias(_stext), 509 (unsigned long)__init_begin - (unsigned long)_stext, 510 PAGE_KERNEL_RO); 511 } 512 513 static bool crash_mem_map __initdata; 514 515 static int __init enable_crash_mem_map(char *arg) 516 { 517 /* 518 * Proper parameter parsing is done by reserve_crashkernel(). We only 519 * need to know if the linear map has to avoid block mappings so that 520 * the crashkernel reservations can be unmapped later. 521 */ 522 crash_mem_map = true; 523 524 return 0; 525 } 526 early_param("crashkernel", enable_crash_mem_map); 527 528 static void __init map_mem(pgd_t *pgdp) 529 { 530 static const u64 direct_map_end = _PAGE_END(VA_BITS_MIN); 531 phys_addr_t kernel_start = __pa_symbol(_stext); 532 phys_addr_t kernel_end = __pa_symbol(__init_begin); 533 phys_addr_t start, end; 534 int flags = NO_EXEC_MAPPINGS; 535 u64 i; 536 537 /* 538 * Setting hierarchical PXNTable attributes on table entries covering 539 * the linear region is only possible if it is guaranteed that no table 540 * entries at any level are being shared between the linear region and 541 * the vmalloc region. Check whether this is true for the PGD level, in 542 * which case it is guaranteed to be true for all other levels as well. 543 */ 544 BUILD_BUG_ON(pgd_index(direct_map_end - 1) == pgd_index(direct_map_end)); 545 546 if (can_set_direct_map()) 547 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 548 549 /* 550 * Take care not to create a writable alias for the 551 * read-only text and rodata sections of the kernel image. 552 * So temporarily mark them as NOMAP to skip mappings in 553 * the following for-loop 554 */ 555 memblock_mark_nomap(kernel_start, kernel_end - kernel_start); 556 557 #ifdef CONFIG_KEXEC_CORE 558 if (crash_mem_map) { 559 if (defer_reserve_crashkernel()) 560 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 561 else if (crashk_res.end) 562 memblock_mark_nomap(crashk_res.start, 563 resource_size(&crashk_res)); 564 } 565 #endif 566 567 /* map all the memory banks */ 568 for_each_mem_range(i, &start, &end) { 569 if (start >= end) 570 break; 571 /* 572 * The linear map must allow allocation tags reading/writing 573 * if MTE is present. Otherwise, it has the same attributes as 574 * PAGE_KERNEL. 575 */ 576 __map_memblock(pgdp, start, end, pgprot_tagged(PAGE_KERNEL), 577 flags); 578 } 579 580 /* 581 * Map the linear alias of the [_stext, __init_begin) interval 582 * as non-executable now, and remove the write permission in 583 * mark_linear_text_alias_ro() below (which will be called after 584 * alternative patching has completed). This makes the contents 585 * of the region accessible to subsystems such as hibernate, 586 * but protects it from inadvertent modification or execution. 587 * Note that contiguous mappings cannot be remapped in this way, 588 * so we should avoid them here. 589 */ 590 __map_memblock(pgdp, kernel_start, kernel_end, 591 PAGE_KERNEL, NO_CONT_MAPPINGS); 592 memblock_clear_nomap(kernel_start, kernel_end - kernel_start); 593 594 /* 595 * Use page-level mappings here so that we can shrink the region 596 * in page granularity and put back unused memory to buddy system 597 * through /sys/kernel/kexec_crash_size interface. 598 */ 599 #ifdef CONFIG_KEXEC_CORE 600 if (crash_mem_map && !defer_reserve_crashkernel()) { 601 if (crashk_res.end) { 602 __map_memblock(pgdp, crashk_res.start, 603 crashk_res.end + 1, 604 PAGE_KERNEL, 605 NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS); 606 memblock_clear_nomap(crashk_res.start, 607 resource_size(&crashk_res)); 608 } 609 } 610 #endif 611 } 612 613 void mark_rodata_ro(void) 614 { 615 unsigned long section_size; 616 617 /* 618 * mark .rodata as read only. Use __init_begin rather than __end_rodata 619 * to cover NOTES and EXCEPTION_TABLE. 620 */ 621 section_size = (unsigned long)__init_begin - (unsigned long)__start_rodata; 622 update_mapping_prot(__pa_symbol(__start_rodata), (unsigned long)__start_rodata, 623 section_size, PAGE_KERNEL_RO); 624 625 debug_checkwx(); 626 } 627 628 static void __init map_kernel_segment(pgd_t *pgdp, void *va_start, void *va_end, 629 pgprot_t prot, struct vm_struct *vma, 630 int flags, unsigned long vm_flags) 631 { 632 phys_addr_t pa_start = __pa_symbol(va_start); 633 unsigned long size = va_end - va_start; 634 635 BUG_ON(!PAGE_ALIGNED(pa_start)); 636 BUG_ON(!PAGE_ALIGNED(size)); 637 638 __create_pgd_mapping(pgdp, pa_start, (unsigned long)va_start, size, prot, 639 early_pgtable_alloc, flags); 640 641 if (!(vm_flags & VM_NO_GUARD)) 642 size += PAGE_SIZE; 643 644 vma->addr = va_start; 645 vma->phys_addr = pa_start; 646 vma->size = size; 647 vma->flags = VM_MAP | vm_flags; 648 vma->caller = __builtin_return_address(0); 649 650 vm_area_add_early(vma); 651 } 652 653 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 654 static int __init map_entry_trampoline(void) 655 { 656 int i; 657 658 pgprot_t prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 659 phys_addr_t pa_start = __pa_symbol(__entry_tramp_text_start); 660 661 /* The trampoline is always mapped and can therefore be global */ 662 pgprot_val(prot) &= ~PTE_NG; 663 664 /* Map only the text into the trampoline page table */ 665 memset(tramp_pg_dir, 0, PGD_SIZE); 666 __create_pgd_mapping(tramp_pg_dir, pa_start, TRAMP_VALIAS, 667 entry_tramp_text_size(), prot, 668 __pgd_pgtable_alloc, NO_BLOCK_MAPPINGS); 669 670 /* Map both the text and data into the kernel page table */ 671 for (i = 0; i < DIV_ROUND_UP(entry_tramp_text_size(), PAGE_SIZE); i++) 672 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 673 pa_start + i * PAGE_SIZE, prot); 674 675 if (IS_ENABLED(CONFIG_RELOCATABLE)) 676 __set_fixmap(FIX_ENTRY_TRAMP_TEXT1 - i, 677 pa_start + i * PAGE_SIZE, PAGE_KERNEL_RO); 678 679 return 0; 680 } 681 core_initcall(map_entry_trampoline); 682 #endif 683 684 /* 685 * Open coded check for BTI, only for use to determine configuration 686 * for early mappings for before the cpufeature code has run. 687 */ 688 static bool arm64_early_this_cpu_has_bti(void) 689 { 690 u64 pfr1; 691 692 if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) 693 return false; 694 695 pfr1 = __read_sysreg_by_encoding(SYS_ID_AA64PFR1_EL1); 696 return cpuid_feature_extract_unsigned_field(pfr1, 697 ID_AA64PFR1_EL1_BT_SHIFT); 698 } 699 700 /* 701 * Create fine-grained mappings for the kernel. 702 */ 703 static void __init map_kernel(pgd_t *pgdp) 704 { 705 static struct vm_struct vmlinux_text, vmlinux_rodata, vmlinux_inittext, 706 vmlinux_initdata, vmlinux_data; 707 708 /* 709 * External debuggers may need to write directly to the text 710 * mapping to install SW breakpoints. Allow this (only) when 711 * explicitly requested with rodata=off. 712 */ 713 pgprot_t text_prot = rodata_enabled ? PAGE_KERNEL_ROX : PAGE_KERNEL_EXEC; 714 715 /* 716 * If we have a CPU that supports BTI and a kernel built for 717 * BTI then mark the kernel executable text as guarded pages 718 * now so we don't have to rewrite the page tables later. 719 */ 720 if (arm64_early_this_cpu_has_bti()) 721 text_prot = __pgprot_modify(text_prot, PTE_GP, PTE_GP); 722 723 /* 724 * Only rodata will be remapped with different permissions later on, 725 * all other segments are allowed to use contiguous mappings. 726 */ 727 map_kernel_segment(pgdp, _stext, _etext, text_prot, &vmlinux_text, 0, 728 VM_NO_GUARD); 729 map_kernel_segment(pgdp, __start_rodata, __inittext_begin, PAGE_KERNEL, 730 &vmlinux_rodata, NO_CONT_MAPPINGS, VM_NO_GUARD); 731 map_kernel_segment(pgdp, __inittext_begin, __inittext_end, text_prot, 732 &vmlinux_inittext, 0, VM_NO_GUARD); 733 map_kernel_segment(pgdp, __initdata_begin, __initdata_end, PAGE_KERNEL, 734 &vmlinux_initdata, 0, VM_NO_GUARD); 735 map_kernel_segment(pgdp, _data, _end, PAGE_KERNEL, &vmlinux_data, 0, 0); 736 737 if (!READ_ONCE(pgd_val(*pgd_offset_pgd(pgdp, FIXADDR_START)))) { 738 /* 739 * The fixmap falls in a separate pgd to the kernel, and doesn't 740 * live in the carveout for the swapper_pg_dir. We can simply 741 * re-use the existing dir for the fixmap. 742 */ 743 set_pgd(pgd_offset_pgd(pgdp, FIXADDR_START), 744 READ_ONCE(*pgd_offset_k(FIXADDR_START))); 745 } else if (CONFIG_PGTABLE_LEVELS > 3) { 746 pgd_t *bm_pgdp; 747 p4d_t *bm_p4dp; 748 pud_t *bm_pudp; 749 /* 750 * The fixmap shares its top level pgd entry with the kernel 751 * mapping. This can really only occur when we are running 752 * with 16k/4 levels, so we can simply reuse the pud level 753 * entry instead. 754 */ 755 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 756 bm_pgdp = pgd_offset_pgd(pgdp, FIXADDR_START); 757 bm_p4dp = p4d_offset(bm_pgdp, FIXADDR_START); 758 bm_pudp = pud_set_fixmap_offset(bm_p4dp, FIXADDR_START); 759 pud_populate(&init_mm, bm_pudp, lm_alias(bm_pmd)); 760 pud_clear_fixmap(); 761 } else { 762 BUG(); 763 } 764 765 kasan_copy_shadow(pgdp); 766 } 767 768 static void __init create_idmap(void) 769 { 770 u64 start = __pa_symbol(__idmap_text_start); 771 u64 size = __pa_symbol(__idmap_text_end) - start; 772 pgd_t *pgd = idmap_pg_dir; 773 u64 pgd_phys; 774 775 /* check if we need an additional level of translation */ 776 if (VA_BITS < 48 && idmap_t0sz < (64 - VA_BITS_MIN)) { 777 pgd_phys = early_pgtable_alloc(PAGE_SHIFT); 778 set_pgd(&idmap_pg_dir[start >> VA_BITS], 779 __pgd(pgd_phys | P4D_TYPE_TABLE)); 780 pgd = __va(pgd_phys); 781 } 782 __create_pgd_mapping(pgd, start, start, size, PAGE_KERNEL_ROX, 783 early_pgtable_alloc, 0); 784 785 if (IS_ENABLED(CONFIG_UNMAP_KERNEL_AT_EL0)) { 786 extern u32 __idmap_kpti_flag; 787 u64 pa = __pa_symbol(&__idmap_kpti_flag); 788 789 /* 790 * The KPTI G-to-nG conversion code needs a read-write mapping 791 * of its synchronization flag in the ID map. 792 */ 793 __create_pgd_mapping(pgd, pa, pa, sizeof(u32), PAGE_KERNEL, 794 early_pgtable_alloc, 0); 795 } 796 } 797 798 void __init paging_init(void) 799 { 800 pgd_t *pgdp = pgd_set_fixmap(__pa_symbol(swapper_pg_dir)); 801 extern pgd_t init_idmap_pg_dir[]; 802 803 idmap_t0sz = 63UL - __fls(__pa_symbol(_end) | GENMASK(VA_BITS_MIN - 1, 0)); 804 805 map_kernel(pgdp); 806 map_mem(pgdp); 807 808 pgd_clear_fixmap(); 809 810 cpu_replace_ttbr1(lm_alias(swapper_pg_dir), init_idmap_pg_dir); 811 init_mm.pgd = swapper_pg_dir; 812 813 memblock_phys_free(__pa_symbol(init_pg_dir), 814 __pa_symbol(init_pg_end) - __pa_symbol(init_pg_dir)); 815 816 memblock_allow_resize(); 817 818 create_idmap(); 819 } 820 821 #ifdef CONFIG_MEMORY_HOTPLUG 822 static void free_hotplug_page_range(struct page *page, size_t size, 823 struct vmem_altmap *altmap) 824 { 825 if (altmap) { 826 vmem_altmap_free(altmap, size >> PAGE_SHIFT); 827 } else { 828 WARN_ON(PageReserved(page)); 829 free_pages((unsigned long)page_address(page), get_order(size)); 830 } 831 } 832 833 static void free_hotplug_pgtable_page(struct page *page) 834 { 835 free_hotplug_page_range(page, PAGE_SIZE, NULL); 836 } 837 838 static bool pgtable_range_aligned(unsigned long start, unsigned long end, 839 unsigned long floor, unsigned long ceiling, 840 unsigned long mask) 841 { 842 start &= mask; 843 if (start < floor) 844 return false; 845 846 if (ceiling) { 847 ceiling &= mask; 848 if (!ceiling) 849 return false; 850 } 851 852 if (end - 1 > ceiling - 1) 853 return false; 854 return true; 855 } 856 857 static void unmap_hotplug_pte_range(pmd_t *pmdp, unsigned long addr, 858 unsigned long end, bool free_mapped, 859 struct vmem_altmap *altmap) 860 { 861 pte_t *ptep, pte; 862 863 do { 864 ptep = pte_offset_kernel(pmdp, addr); 865 pte = READ_ONCE(*ptep); 866 if (pte_none(pte)) 867 continue; 868 869 WARN_ON(!pte_present(pte)); 870 pte_clear(&init_mm, addr, ptep); 871 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 872 if (free_mapped) 873 free_hotplug_page_range(pte_page(pte), 874 PAGE_SIZE, altmap); 875 } while (addr += PAGE_SIZE, addr < end); 876 } 877 878 static void unmap_hotplug_pmd_range(pud_t *pudp, unsigned long addr, 879 unsigned long end, bool free_mapped, 880 struct vmem_altmap *altmap) 881 { 882 unsigned long next; 883 pmd_t *pmdp, pmd; 884 885 do { 886 next = pmd_addr_end(addr, end); 887 pmdp = pmd_offset(pudp, addr); 888 pmd = READ_ONCE(*pmdp); 889 if (pmd_none(pmd)) 890 continue; 891 892 WARN_ON(!pmd_present(pmd)); 893 if (pmd_sect(pmd)) { 894 pmd_clear(pmdp); 895 896 /* 897 * One TLBI should be sufficient here as the PMD_SIZE 898 * range is mapped with a single block entry. 899 */ 900 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 901 if (free_mapped) 902 free_hotplug_page_range(pmd_page(pmd), 903 PMD_SIZE, altmap); 904 continue; 905 } 906 WARN_ON(!pmd_table(pmd)); 907 unmap_hotplug_pte_range(pmdp, addr, next, free_mapped, altmap); 908 } while (addr = next, addr < end); 909 } 910 911 static void unmap_hotplug_pud_range(p4d_t *p4dp, unsigned long addr, 912 unsigned long end, bool free_mapped, 913 struct vmem_altmap *altmap) 914 { 915 unsigned long next; 916 pud_t *pudp, pud; 917 918 do { 919 next = pud_addr_end(addr, end); 920 pudp = pud_offset(p4dp, addr); 921 pud = READ_ONCE(*pudp); 922 if (pud_none(pud)) 923 continue; 924 925 WARN_ON(!pud_present(pud)); 926 if (pud_sect(pud)) { 927 pud_clear(pudp); 928 929 /* 930 * One TLBI should be sufficient here as the PUD_SIZE 931 * range is mapped with a single block entry. 932 */ 933 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 934 if (free_mapped) 935 free_hotplug_page_range(pud_page(pud), 936 PUD_SIZE, altmap); 937 continue; 938 } 939 WARN_ON(!pud_table(pud)); 940 unmap_hotplug_pmd_range(pudp, addr, next, free_mapped, altmap); 941 } while (addr = next, addr < end); 942 } 943 944 static void unmap_hotplug_p4d_range(pgd_t *pgdp, unsigned long addr, 945 unsigned long end, bool free_mapped, 946 struct vmem_altmap *altmap) 947 { 948 unsigned long next; 949 p4d_t *p4dp, p4d; 950 951 do { 952 next = p4d_addr_end(addr, end); 953 p4dp = p4d_offset(pgdp, addr); 954 p4d = READ_ONCE(*p4dp); 955 if (p4d_none(p4d)) 956 continue; 957 958 WARN_ON(!p4d_present(p4d)); 959 unmap_hotplug_pud_range(p4dp, addr, next, free_mapped, altmap); 960 } while (addr = next, addr < end); 961 } 962 963 static void unmap_hotplug_range(unsigned long addr, unsigned long end, 964 bool free_mapped, struct vmem_altmap *altmap) 965 { 966 unsigned long next; 967 pgd_t *pgdp, pgd; 968 969 /* 970 * altmap can only be used as vmemmap mapping backing memory. 971 * In case the backing memory itself is not being freed, then 972 * altmap is irrelevant. Warn about this inconsistency when 973 * encountered. 974 */ 975 WARN_ON(!free_mapped && altmap); 976 977 do { 978 next = pgd_addr_end(addr, end); 979 pgdp = pgd_offset_k(addr); 980 pgd = READ_ONCE(*pgdp); 981 if (pgd_none(pgd)) 982 continue; 983 984 WARN_ON(!pgd_present(pgd)); 985 unmap_hotplug_p4d_range(pgdp, addr, next, free_mapped, altmap); 986 } while (addr = next, addr < end); 987 } 988 989 static void free_empty_pte_table(pmd_t *pmdp, unsigned long addr, 990 unsigned long end, unsigned long floor, 991 unsigned long ceiling) 992 { 993 pte_t *ptep, pte; 994 unsigned long i, start = addr; 995 996 do { 997 ptep = pte_offset_kernel(pmdp, addr); 998 pte = READ_ONCE(*ptep); 999 1000 /* 1001 * This is just a sanity check here which verifies that 1002 * pte clearing has been done by earlier unmap loops. 1003 */ 1004 WARN_ON(!pte_none(pte)); 1005 } while (addr += PAGE_SIZE, addr < end); 1006 1007 if (!pgtable_range_aligned(start, end, floor, ceiling, PMD_MASK)) 1008 return; 1009 1010 /* 1011 * Check whether we can free the pte page if the rest of the 1012 * entries are empty. Overlap with other regions have been 1013 * handled by the floor/ceiling check. 1014 */ 1015 ptep = pte_offset_kernel(pmdp, 0UL); 1016 for (i = 0; i < PTRS_PER_PTE; i++) { 1017 if (!pte_none(READ_ONCE(ptep[i]))) 1018 return; 1019 } 1020 1021 pmd_clear(pmdp); 1022 __flush_tlb_kernel_pgtable(start); 1023 free_hotplug_pgtable_page(virt_to_page(ptep)); 1024 } 1025 1026 static void free_empty_pmd_table(pud_t *pudp, unsigned long addr, 1027 unsigned long end, unsigned long floor, 1028 unsigned long ceiling) 1029 { 1030 pmd_t *pmdp, pmd; 1031 unsigned long i, next, start = addr; 1032 1033 do { 1034 next = pmd_addr_end(addr, end); 1035 pmdp = pmd_offset(pudp, addr); 1036 pmd = READ_ONCE(*pmdp); 1037 if (pmd_none(pmd)) 1038 continue; 1039 1040 WARN_ON(!pmd_present(pmd) || !pmd_table(pmd) || pmd_sect(pmd)); 1041 free_empty_pte_table(pmdp, addr, next, floor, ceiling); 1042 } while (addr = next, addr < end); 1043 1044 if (CONFIG_PGTABLE_LEVELS <= 2) 1045 return; 1046 1047 if (!pgtable_range_aligned(start, end, floor, ceiling, PUD_MASK)) 1048 return; 1049 1050 /* 1051 * Check whether we can free the pmd page if the rest of the 1052 * entries are empty. Overlap with other regions have been 1053 * handled by the floor/ceiling check. 1054 */ 1055 pmdp = pmd_offset(pudp, 0UL); 1056 for (i = 0; i < PTRS_PER_PMD; i++) { 1057 if (!pmd_none(READ_ONCE(pmdp[i]))) 1058 return; 1059 } 1060 1061 pud_clear(pudp); 1062 __flush_tlb_kernel_pgtable(start); 1063 free_hotplug_pgtable_page(virt_to_page(pmdp)); 1064 } 1065 1066 static void free_empty_pud_table(p4d_t *p4dp, unsigned long addr, 1067 unsigned long end, unsigned long floor, 1068 unsigned long ceiling) 1069 { 1070 pud_t *pudp, pud; 1071 unsigned long i, next, start = addr; 1072 1073 do { 1074 next = pud_addr_end(addr, end); 1075 pudp = pud_offset(p4dp, addr); 1076 pud = READ_ONCE(*pudp); 1077 if (pud_none(pud)) 1078 continue; 1079 1080 WARN_ON(!pud_present(pud) || !pud_table(pud) || pud_sect(pud)); 1081 free_empty_pmd_table(pudp, addr, next, floor, ceiling); 1082 } while (addr = next, addr < end); 1083 1084 if (CONFIG_PGTABLE_LEVELS <= 3) 1085 return; 1086 1087 if (!pgtable_range_aligned(start, end, floor, ceiling, PGDIR_MASK)) 1088 return; 1089 1090 /* 1091 * Check whether we can free the pud page if the rest of the 1092 * entries are empty. Overlap with other regions have been 1093 * handled by the floor/ceiling check. 1094 */ 1095 pudp = pud_offset(p4dp, 0UL); 1096 for (i = 0; i < PTRS_PER_PUD; i++) { 1097 if (!pud_none(READ_ONCE(pudp[i]))) 1098 return; 1099 } 1100 1101 p4d_clear(p4dp); 1102 __flush_tlb_kernel_pgtable(start); 1103 free_hotplug_pgtable_page(virt_to_page(pudp)); 1104 } 1105 1106 static void free_empty_p4d_table(pgd_t *pgdp, unsigned long addr, 1107 unsigned long end, unsigned long floor, 1108 unsigned long ceiling) 1109 { 1110 unsigned long next; 1111 p4d_t *p4dp, p4d; 1112 1113 do { 1114 next = p4d_addr_end(addr, end); 1115 p4dp = p4d_offset(pgdp, addr); 1116 p4d = READ_ONCE(*p4dp); 1117 if (p4d_none(p4d)) 1118 continue; 1119 1120 WARN_ON(!p4d_present(p4d)); 1121 free_empty_pud_table(p4dp, addr, next, floor, ceiling); 1122 } while (addr = next, addr < end); 1123 } 1124 1125 static void free_empty_tables(unsigned long addr, unsigned long end, 1126 unsigned long floor, unsigned long ceiling) 1127 { 1128 unsigned long next; 1129 pgd_t *pgdp, pgd; 1130 1131 do { 1132 next = pgd_addr_end(addr, end); 1133 pgdp = pgd_offset_k(addr); 1134 pgd = READ_ONCE(*pgdp); 1135 if (pgd_none(pgd)) 1136 continue; 1137 1138 WARN_ON(!pgd_present(pgd)); 1139 free_empty_p4d_table(pgdp, addr, next, floor, ceiling); 1140 } while (addr = next, addr < end); 1141 } 1142 #endif 1143 1144 void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node, 1145 unsigned long addr, unsigned long next) 1146 { 1147 pmd_set_huge(pmdp, __pa(p), __pgprot(PROT_SECT_NORMAL)); 1148 } 1149 1150 int __meminit vmemmap_check_pmd(pmd_t *pmdp, int node, 1151 unsigned long addr, unsigned long next) 1152 { 1153 vmemmap_verify((pte_t *)pmdp, node, addr, next); 1154 return 1; 1155 } 1156 1157 int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, 1158 struct vmem_altmap *altmap) 1159 { 1160 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1161 1162 if (!IS_ENABLED(CONFIG_ARM64_4K_PAGES)) 1163 return vmemmap_populate_basepages(start, end, node, altmap); 1164 else 1165 return vmemmap_populate_hugepages(start, end, node, altmap); 1166 } 1167 1168 #ifdef CONFIG_MEMORY_HOTPLUG 1169 void vmemmap_free(unsigned long start, unsigned long end, 1170 struct vmem_altmap *altmap) 1171 { 1172 WARN_ON((start < VMEMMAP_START) || (end > VMEMMAP_END)); 1173 1174 unmap_hotplug_range(start, end, true, altmap); 1175 free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END); 1176 } 1177 #endif /* CONFIG_MEMORY_HOTPLUG */ 1178 1179 static inline pud_t *fixmap_pud(unsigned long addr) 1180 { 1181 pgd_t *pgdp = pgd_offset_k(addr); 1182 p4d_t *p4dp = p4d_offset(pgdp, addr); 1183 p4d_t p4d = READ_ONCE(*p4dp); 1184 1185 BUG_ON(p4d_none(p4d) || p4d_bad(p4d)); 1186 1187 return pud_offset_kimg(p4dp, addr); 1188 } 1189 1190 static inline pmd_t *fixmap_pmd(unsigned long addr) 1191 { 1192 pud_t *pudp = fixmap_pud(addr); 1193 pud_t pud = READ_ONCE(*pudp); 1194 1195 BUG_ON(pud_none(pud) || pud_bad(pud)); 1196 1197 return pmd_offset_kimg(pudp, addr); 1198 } 1199 1200 static inline pte_t *fixmap_pte(unsigned long addr) 1201 { 1202 return &bm_pte[pte_index(addr)]; 1203 } 1204 1205 /* 1206 * The p*d_populate functions call virt_to_phys implicitly so they can't be used 1207 * directly on kernel symbols (bm_p*d). This function is called too early to use 1208 * lm_alias so __p*d_populate functions must be used to populate with the 1209 * physical address from __pa_symbol. 1210 */ 1211 void __init early_fixmap_init(void) 1212 { 1213 pgd_t *pgdp; 1214 p4d_t *p4dp, p4d; 1215 pud_t *pudp; 1216 pmd_t *pmdp; 1217 unsigned long addr = FIXADDR_START; 1218 1219 pgdp = pgd_offset_k(addr); 1220 p4dp = p4d_offset(pgdp, addr); 1221 p4d = READ_ONCE(*p4dp); 1222 if (CONFIG_PGTABLE_LEVELS > 3 && 1223 !(p4d_none(p4d) || p4d_page_paddr(p4d) == __pa_symbol(bm_pud))) { 1224 /* 1225 * We only end up here if the kernel mapping and the fixmap 1226 * share the top level pgd entry, which should only happen on 1227 * 16k/4 levels configurations. 1228 */ 1229 BUG_ON(!IS_ENABLED(CONFIG_ARM64_16K_PAGES)); 1230 pudp = pud_offset_kimg(p4dp, addr); 1231 } else { 1232 if (p4d_none(p4d)) 1233 __p4d_populate(p4dp, __pa_symbol(bm_pud), P4D_TYPE_TABLE); 1234 pudp = fixmap_pud(addr); 1235 } 1236 if (pud_none(READ_ONCE(*pudp))) 1237 __pud_populate(pudp, __pa_symbol(bm_pmd), PUD_TYPE_TABLE); 1238 pmdp = fixmap_pmd(addr); 1239 __pmd_populate(pmdp, __pa_symbol(bm_pte), PMD_TYPE_TABLE); 1240 1241 /* 1242 * The boot-ioremap range spans multiple pmds, for which 1243 * we are not prepared: 1244 */ 1245 BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT) 1246 != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT)); 1247 1248 if ((pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN))) 1249 || pmdp != fixmap_pmd(fix_to_virt(FIX_BTMAP_END))) { 1250 WARN_ON(1); 1251 pr_warn("pmdp %p != %p, %p\n", 1252 pmdp, fixmap_pmd(fix_to_virt(FIX_BTMAP_BEGIN)), 1253 fixmap_pmd(fix_to_virt(FIX_BTMAP_END))); 1254 pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n", 1255 fix_to_virt(FIX_BTMAP_BEGIN)); 1256 pr_warn("fix_to_virt(FIX_BTMAP_END): %08lx\n", 1257 fix_to_virt(FIX_BTMAP_END)); 1258 1259 pr_warn("FIX_BTMAP_END: %d\n", FIX_BTMAP_END); 1260 pr_warn("FIX_BTMAP_BEGIN: %d\n", FIX_BTMAP_BEGIN); 1261 } 1262 } 1263 1264 /* 1265 * Unusually, this is also called in IRQ context (ghes_iounmap_irq) so if we 1266 * ever need to use IPIs for TLB broadcasting, then we're in trouble here. 1267 */ 1268 void __set_fixmap(enum fixed_addresses idx, 1269 phys_addr_t phys, pgprot_t flags) 1270 { 1271 unsigned long addr = __fix_to_virt(idx); 1272 pte_t *ptep; 1273 1274 BUG_ON(idx <= FIX_HOLE || idx >= __end_of_fixed_addresses); 1275 1276 ptep = fixmap_pte(addr); 1277 1278 if (pgprot_val(flags)) { 1279 set_pte(ptep, pfn_pte(phys >> PAGE_SHIFT, flags)); 1280 } else { 1281 pte_clear(&init_mm, addr, ptep); 1282 flush_tlb_kernel_range(addr, addr+PAGE_SIZE); 1283 } 1284 } 1285 1286 void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) 1287 { 1288 const u64 dt_virt_base = __fix_to_virt(FIX_FDT); 1289 int offset; 1290 void *dt_virt; 1291 1292 /* 1293 * Check whether the physical FDT address is set and meets the minimum 1294 * alignment requirement. Since we are relying on MIN_FDT_ALIGN to be 1295 * at least 8 bytes so that we can always access the magic and size 1296 * fields of the FDT header after mapping the first chunk, double check 1297 * here if that is indeed the case. 1298 */ 1299 BUILD_BUG_ON(MIN_FDT_ALIGN < 8); 1300 if (!dt_phys || dt_phys % MIN_FDT_ALIGN) 1301 return NULL; 1302 1303 /* 1304 * Make sure that the FDT region can be mapped without the need to 1305 * allocate additional translation table pages, so that it is safe 1306 * to call create_mapping_noalloc() this early. 1307 * 1308 * On 64k pages, the FDT will be mapped using PTEs, so we need to 1309 * be in the same PMD as the rest of the fixmap. 1310 * On 4k pages, we'll use section mappings for the FDT so we only 1311 * have to be in the same PUD. 1312 */ 1313 BUILD_BUG_ON(dt_virt_base % SZ_2M); 1314 1315 BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT != 1316 __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT); 1317 1318 offset = dt_phys % SWAPPER_BLOCK_SIZE; 1319 dt_virt = (void *)dt_virt_base + offset; 1320 1321 /* map the first chunk so we can read the size from the header */ 1322 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), 1323 dt_virt_base, SWAPPER_BLOCK_SIZE, prot); 1324 1325 if (fdt_magic(dt_virt) != FDT_MAGIC) 1326 return NULL; 1327 1328 *size = fdt_totalsize(dt_virt); 1329 if (*size > MAX_FDT_SIZE) 1330 return NULL; 1331 1332 if (offset + *size > SWAPPER_BLOCK_SIZE) 1333 create_mapping_noalloc(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base, 1334 round_up(offset + *size, SWAPPER_BLOCK_SIZE), prot); 1335 1336 return dt_virt; 1337 } 1338 1339 int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) 1340 { 1341 pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); 1342 1343 /* Only allow permission changes for now */ 1344 if (!pgattr_change_is_safe(READ_ONCE(pud_val(*pudp)), 1345 pud_val(new_pud))) 1346 return 0; 1347 1348 VM_BUG_ON(phys & ~PUD_MASK); 1349 set_pud(pudp, new_pud); 1350 return 1; 1351 } 1352 1353 int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) 1354 { 1355 pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); 1356 1357 /* Only allow permission changes for now */ 1358 if (!pgattr_change_is_safe(READ_ONCE(pmd_val(*pmdp)), 1359 pmd_val(new_pmd))) 1360 return 0; 1361 1362 VM_BUG_ON(phys & ~PMD_MASK); 1363 set_pmd(pmdp, new_pmd); 1364 return 1; 1365 } 1366 1367 int pud_clear_huge(pud_t *pudp) 1368 { 1369 if (!pud_sect(READ_ONCE(*pudp))) 1370 return 0; 1371 pud_clear(pudp); 1372 return 1; 1373 } 1374 1375 int pmd_clear_huge(pmd_t *pmdp) 1376 { 1377 if (!pmd_sect(READ_ONCE(*pmdp))) 1378 return 0; 1379 pmd_clear(pmdp); 1380 return 1; 1381 } 1382 1383 int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) 1384 { 1385 pte_t *table; 1386 pmd_t pmd; 1387 1388 pmd = READ_ONCE(*pmdp); 1389 1390 if (!pmd_table(pmd)) { 1391 VM_WARN_ON(1); 1392 return 1; 1393 } 1394 1395 table = pte_offset_kernel(pmdp, addr); 1396 pmd_clear(pmdp); 1397 __flush_tlb_kernel_pgtable(addr); 1398 pte_free_kernel(NULL, table); 1399 return 1; 1400 } 1401 1402 int pud_free_pmd_page(pud_t *pudp, unsigned long addr) 1403 { 1404 pmd_t *table; 1405 pmd_t *pmdp; 1406 pud_t pud; 1407 unsigned long next, end; 1408 1409 pud = READ_ONCE(*pudp); 1410 1411 if (!pud_table(pud)) { 1412 VM_WARN_ON(1); 1413 return 1; 1414 } 1415 1416 table = pmd_offset(pudp, addr); 1417 pmdp = table; 1418 next = addr; 1419 end = addr + PUD_SIZE; 1420 do { 1421 pmd_free_pte_page(pmdp, next); 1422 } while (pmdp++, next += PMD_SIZE, next != end); 1423 1424 pud_clear(pudp); 1425 __flush_tlb_kernel_pgtable(addr); 1426 pmd_free(NULL, table); 1427 return 1; 1428 } 1429 1430 #ifdef CONFIG_MEMORY_HOTPLUG 1431 static void __remove_pgd_mapping(pgd_t *pgdir, unsigned long start, u64 size) 1432 { 1433 unsigned long end = start + size; 1434 1435 WARN_ON(pgdir != init_mm.pgd); 1436 WARN_ON((start < PAGE_OFFSET) || (end > PAGE_END)); 1437 1438 unmap_hotplug_range(start, end, false, NULL); 1439 free_empty_tables(start, end, PAGE_OFFSET, PAGE_END); 1440 } 1441 1442 struct range arch_get_mappable_range(void) 1443 { 1444 struct range mhp_range; 1445 u64 start_linear_pa = __pa(_PAGE_OFFSET(vabits_actual)); 1446 u64 end_linear_pa = __pa(PAGE_END - 1); 1447 1448 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { 1449 /* 1450 * Check for a wrap, it is possible because of randomized linear 1451 * mapping the start physical address is actually bigger than 1452 * the end physical address. In this case set start to zero 1453 * because [0, end_linear_pa] range must still be able to cover 1454 * all addressable physical addresses. 1455 */ 1456 if (start_linear_pa > end_linear_pa) 1457 start_linear_pa = 0; 1458 } 1459 1460 WARN_ON(start_linear_pa > end_linear_pa); 1461 1462 /* 1463 * Linear mapping region is the range [PAGE_OFFSET..(PAGE_END - 1)] 1464 * accommodating both its ends but excluding PAGE_END. Max physical 1465 * range which can be mapped inside this linear mapping range, must 1466 * also be derived from its end points. 1467 */ 1468 mhp_range.start = start_linear_pa; 1469 mhp_range.end = end_linear_pa; 1470 1471 return mhp_range; 1472 } 1473 1474 int arch_add_memory(int nid, u64 start, u64 size, 1475 struct mhp_params *params) 1476 { 1477 int ret, flags = NO_EXEC_MAPPINGS; 1478 1479 VM_BUG_ON(!mhp_range_allowed(start, size, true)); 1480 1481 if (can_set_direct_map()) 1482 flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; 1483 1484 __create_pgd_mapping(swapper_pg_dir, start, __phys_to_virt(start), 1485 size, params->pgprot, __pgd_pgtable_alloc, 1486 flags); 1487 1488 memblock_clear_nomap(start, size); 1489 1490 ret = __add_pages(nid, start >> PAGE_SHIFT, size >> PAGE_SHIFT, 1491 params); 1492 if (ret) 1493 __remove_pgd_mapping(swapper_pg_dir, 1494 __phys_to_virt(start), size); 1495 else { 1496 max_pfn = PFN_UP(start + size); 1497 max_low_pfn = max_pfn; 1498 } 1499 1500 return ret; 1501 } 1502 1503 void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap) 1504 { 1505 unsigned long start_pfn = start >> PAGE_SHIFT; 1506 unsigned long nr_pages = size >> PAGE_SHIFT; 1507 1508 __remove_pages(start_pfn, nr_pages, altmap); 1509 __remove_pgd_mapping(swapper_pg_dir, __phys_to_virt(start), size); 1510 } 1511 1512 /* 1513 * This memory hotplug notifier helps prevent boot memory from being 1514 * inadvertently removed as it blocks pfn range offlining process in 1515 * __offline_pages(). Hence this prevents both offlining as well as 1516 * removal process for boot memory which is initially always online. 1517 * In future if and when boot memory could be removed, this notifier 1518 * should be dropped and free_hotplug_page_range() should handle any 1519 * reserved pages allocated during boot. 1520 */ 1521 static int prevent_bootmem_remove_notifier(struct notifier_block *nb, 1522 unsigned long action, void *data) 1523 { 1524 struct mem_section *ms; 1525 struct memory_notify *arg = data; 1526 unsigned long end_pfn = arg->start_pfn + arg->nr_pages; 1527 unsigned long pfn = arg->start_pfn; 1528 1529 if ((action != MEM_GOING_OFFLINE) && (action != MEM_OFFLINE)) 1530 return NOTIFY_OK; 1531 1532 for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) { 1533 unsigned long start = PFN_PHYS(pfn); 1534 unsigned long end = start + (1UL << PA_SECTION_SHIFT); 1535 1536 ms = __pfn_to_section(pfn); 1537 if (!early_section(ms)) 1538 continue; 1539 1540 if (action == MEM_GOING_OFFLINE) { 1541 /* 1542 * Boot memory removal is not supported. Prevent 1543 * it via blocking any attempted offline request 1544 * for the boot memory and just report it. 1545 */ 1546 pr_warn("Boot memory [%lx %lx] offlining attempted\n", start, end); 1547 return NOTIFY_BAD; 1548 } else if (action == MEM_OFFLINE) { 1549 /* 1550 * This should have never happened. Boot memory 1551 * offlining should have been prevented by this 1552 * very notifier. Probably some memory removal 1553 * procedure might have changed which would then 1554 * require further debug. 1555 */ 1556 pr_err("Boot memory [%lx %lx] offlined\n", start, end); 1557 1558 /* 1559 * Core memory hotplug does not process a return 1560 * code from the notifier for MEM_OFFLINE events. 1561 * The error condition has been reported. Return 1562 * from here as if ignored. 1563 */ 1564 return NOTIFY_DONE; 1565 } 1566 } 1567 return NOTIFY_OK; 1568 } 1569 1570 static struct notifier_block prevent_bootmem_remove_nb = { 1571 .notifier_call = prevent_bootmem_remove_notifier, 1572 }; 1573 1574 /* 1575 * This ensures that boot memory sections on the platform are online 1576 * from early boot. Memory sections could not be prevented from being 1577 * offlined, unless for some reason they are not online to begin with. 1578 * This helps validate the basic assumption on which the above memory 1579 * event notifier works to prevent boot memory section offlining and 1580 * its possible removal. 1581 */ 1582 static void validate_bootmem_online(void) 1583 { 1584 phys_addr_t start, end, addr; 1585 struct mem_section *ms; 1586 u64 i; 1587 1588 /* 1589 * Scanning across all memblock might be expensive 1590 * on some big memory systems. Hence enable this 1591 * validation only with DEBUG_VM. 1592 */ 1593 if (!IS_ENABLED(CONFIG_DEBUG_VM)) 1594 return; 1595 1596 for_each_mem_range(i, &start, &end) { 1597 for (addr = start; addr < end; addr += (1UL << PA_SECTION_SHIFT)) { 1598 ms = __pfn_to_section(PHYS_PFN(addr)); 1599 1600 /* 1601 * All memory ranges in the system at this point 1602 * should have been marked as early sections. 1603 */ 1604 WARN_ON(!early_section(ms)); 1605 1606 /* 1607 * Memory notifier mechanism here to prevent boot 1608 * memory offlining depends on the fact that each 1609 * early section memory on the system is initially 1610 * online. Otherwise a given memory section which 1611 * is already offline will be overlooked and can 1612 * be removed completely. Call out such sections. 1613 */ 1614 if (!online_section(ms)) 1615 pr_err("Boot memory [%llx %llx] is offline, can be removed\n", 1616 addr, addr + (1UL << PA_SECTION_SHIFT)); 1617 } 1618 } 1619 } 1620 1621 static int __init prevent_bootmem_remove_init(void) 1622 { 1623 int ret = 0; 1624 1625 if (!IS_ENABLED(CONFIG_MEMORY_HOTREMOVE)) 1626 return ret; 1627 1628 validate_bootmem_online(); 1629 ret = register_memory_notifier(&prevent_bootmem_remove_nb); 1630 if (ret) 1631 pr_err("%s: Notifier registration failed %d\n", __func__, ret); 1632 1633 return ret; 1634 } 1635 early_initcall(prevent_bootmem_remove_init); 1636 #endif 1637 1638 pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep) 1639 { 1640 if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) && 1641 cpus_have_const_cap(ARM64_WORKAROUND_2645198)) { 1642 /* 1643 * Break-before-make (BBM) is required for all user space mappings 1644 * when the permission changes from executable to non-executable 1645 * in cases where cpu is affected with errata #2645198. 1646 */ 1647 if (pte_user_exec(READ_ONCE(*ptep))) 1648 return ptep_clear_flush(vma, addr, ptep); 1649 } 1650 return ptep_get_and_clear(vma->vm_mm, addr, ptep); 1651 } 1652 1653 void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, 1654 pte_t old_pte, pte_t pte) 1655 { 1656 set_pte_at(vma->vm_mm, addr, ptep, pte); 1657 } 1658