1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * 4 * Copyright (C) 1995 Linus Torvalds 5 * 6 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 7 */ 8 9 #include <linux/signal.h> 10 #include <linux/sched.h> 11 #include <linux/kernel.h> 12 #include <linux/errno.h> 13 #include <linux/string.h> 14 #include <linux/types.h> 15 #include <linux/ptrace.h> 16 #include <linux/mman.h> 17 #include <linux/mm.h> 18 #include <linux/hugetlb.h> 19 #include <linux/swap.h> 20 #include <linux/smp.h> 21 #include <linux/init.h> 22 #include <linux/highmem.h> 23 #include <linux/pagemap.h> 24 #include <linux/pci.h> 25 #include <linux/pfn.h> 26 #include <linux/poison.h> 27 #include <linux/memblock.h> 28 #include <linux/proc_fs.h> 29 #include <linux/memory_hotplug.h> 30 #include <linux/initrd.h> 31 #include <linux/cpumask.h> 32 #include <linux/gfp.h> 33 34 #include <asm/asm.h> 35 #include <asm/bios_ebda.h> 36 #include <asm/processor.h> 37 #include <linux/uaccess.h> 38 #include <asm/pgtable.h> 39 #include <asm/dma.h> 40 #include <asm/fixmap.h> 41 #include <asm/e820/api.h> 42 #include <asm/apic.h> 43 #include <asm/bugs.h> 44 #include <asm/tlb.h> 45 #include <asm/tlbflush.h> 46 #include <asm/olpc_ofw.h> 47 #include <asm/pgalloc.h> 48 #include <asm/sections.h> 49 #include <asm/paravirt.h> 50 #include <asm/setup.h> 51 #include <asm/set_memory.h> 52 #include <asm/page_types.h> 53 #include <asm/cpu_entry_area.h> 54 #include <asm/init.h> 55 #include <asm/pgtable_areas.h> 56 57 #include "mm_internal.h" 58 59 unsigned long highstart_pfn, highend_pfn; 60 61 bool __read_mostly __vmalloc_start_set = false; 62 63 /* 64 * Creates a middle page table and puts a pointer to it in the 65 * given global directory entry. This only returns the gd entry 66 * in non-PAE compilation mode, since the middle layer is folded. 67 */ 68 static pmd_t * __init one_md_table_init(pgd_t *pgd) 69 { 70 p4d_t *p4d; 71 pud_t *pud; 72 pmd_t *pmd_table; 73 74 #ifdef CONFIG_X86_PAE 75 if (!(pgd_val(*pgd) & _PAGE_PRESENT)) { 76 pmd_table = (pmd_t *)alloc_low_page(); 77 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT); 78 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); 79 p4d = p4d_offset(pgd, 0); 80 pud = pud_offset(p4d, 0); 81 BUG_ON(pmd_table != pmd_offset(pud, 0)); 82 83 return pmd_table; 84 } 85 #endif 86 p4d = p4d_offset(pgd, 0); 87 pud = pud_offset(p4d, 0); 88 pmd_table = pmd_offset(pud, 0); 89 90 return pmd_table; 91 } 92 93 /* 94 * Create a page table and place a pointer to it in a middle page 95 * directory entry: 96 */ 97 static pte_t * __init one_page_table_init(pmd_t *pmd) 98 { 99 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) { 100 pte_t *page_table = (pte_t *)alloc_low_page(); 101 102 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT); 103 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 104 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 105 } 106 107 return pte_offset_kernel(pmd, 0); 108 } 109 110 pmd_t * __init populate_extra_pmd(unsigned long vaddr) 111 { 112 int pgd_idx = pgd_index(vaddr); 113 int pmd_idx = pmd_index(vaddr); 114 115 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx; 116 } 117 118 pte_t * __init populate_extra_pte(unsigned long vaddr) 119 { 120 int pte_idx = pte_index(vaddr); 121 pmd_t *pmd; 122 123 pmd = populate_extra_pmd(vaddr); 124 return one_page_table_init(pmd) + pte_idx; 125 } 126 127 static unsigned long __init 128 page_table_range_init_count(unsigned long start, unsigned long end) 129 { 130 unsigned long count = 0; 131 #ifdef CONFIG_HIGHMEM 132 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 133 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 134 int pgd_idx, pmd_idx; 135 unsigned long vaddr; 136 137 if (pmd_idx_kmap_begin == pmd_idx_kmap_end) 138 return 0; 139 140 vaddr = start; 141 pgd_idx = pgd_index(vaddr); 142 pmd_idx = pmd_index(vaddr); 143 144 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) { 145 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 146 pmd_idx++) { 147 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin && 148 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) 149 count++; 150 vaddr += PMD_SIZE; 151 } 152 pmd_idx = 0; 153 } 154 #endif 155 return count; 156 } 157 158 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd, 159 unsigned long vaddr, pte_t *lastpte, 160 void **adr) 161 { 162 #ifdef CONFIG_HIGHMEM 163 /* 164 * Something (early fixmap) may already have put a pte 165 * page here, which causes the page table allocation 166 * to become nonlinear. Attempt to fix it, and if it 167 * is still nonlinear then we have to bug. 168 */ 169 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 170 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 171 172 if (pmd_idx_kmap_begin != pmd_idx_kmap_end 173 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin 174 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) { 175 pte_t *newpte; 176 int i; 177 178 BUG_ON(after_bootmem); 179 newpte = *adr; 180 for (i = 0; i < PTRS_PER_PTE; i++) 181 set_pte(newpte + i, pte[i]); 182 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE); 183 184 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT); 185 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE)); 186 BUG_ON(newpte != pte_offset_kernel(pmd, 0)); 187 __flush_tlb_all(); 188 189 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT); 190 pte = newpte; 191 } 192 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1) 193 && vaddr > fix_to_virt(FIX_KMAP_END) 194 && lastpte && lastpte + PTRS_PER_PTE != pte); 195 #endif 196 return pte; 197 } 198 199 /* 200 * This function initializes a certain range of kernel virtual memory 201 * with new bootmem page tables, everywhere page tables are missing in 202 * the given range. 203 * 204 * NOTE: The pagetables are allocated contiguous on the physical space 205 * so we can cache the place of the first one and move around without 206 * checking the pgd every time. 207 */ 208 static void __init 209 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 210 { 211 int pgd_idx, pmd_idx; 212 unsigned long vaddr; 213 pgd_t *pgd; 214 pmd_t *pmd; 215 pte_t *pte = NULL; 216 unsigned long count = page_table_range_init_count(start, end); 217 void *adr = NULL; 218 219 if (count) 220 adr = alloc_low_pages(count); 221 222 vaddr = start; 223 pgd_idx = pgd_index(vaddr); 224 pmd_idx = pmd_index(vaddr); 225 pgd = pgd_base + pgd_idx; 226 227 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 228 pmd = one_md_table_init(pgd); 229 pmd = pmd + pmd_index(vaddr); 230 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 231 pmd++, pmd_idx++) { 232 pte = page_table_kmap_check(one_page_table_init(pmd), 233 pmd, vaddr, pte, &adr); 234 235 vaddr += PMD_SIZE; 236 } 237 pmd_idx = 0; 238 } 239 } 240 241 static inline int is_kernel_text(unsigned long addr) 242 { 243 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) 244 return 1; 245 return 0; 246 } 247 248 /* 249 * This maps the physical memory to kernel virtual address space, a total 250 * of max_low_pfn pages, by creating page tables starting from address 251 * PAGE_OFFSET: 252 */ 253 unsigned long __init 254 kernel_physical_mapping_init(unsigned long start, 255 unsigned long end, 256 unsigned long page_size_mask) 257 { 258 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 259 unsigned long last_map_addr = end; 260 unsigned long start_pfn, end_pfn; 261 pgd_t *pgd_base = swapper_pg_dir; 262 int pgd_idx, pmd_idx, pte_ofs; 263 unsigned long pfn; 264 pgd_t *pgd; 265 pmd_t *pmd; 266 pte_t *pte; 267 unsigned pages_2m, pages_4k; 268 int mapping_iter; 269 270 start_pfn = start >> PAGE_SHIFT; 271 end_pfn = end >> PAGE_SHIFT; 272 273 /* 274 * First iteration will setup identity mapping using large/small pages 275 * based on use_pse, with other attributes same as set by 276 * the early code in head_32.S 277 * 278 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 279 * as desired for the kernel identity mapping. 280 * 281 * This two pass mechanism conforms to the TLB app note which says: 282 * 283 * "Software should not write to a paging-structure entry in a way 284 * that would change, for any linear address, both the page size 285 * and either the page frame or attributes." 286 */ 287 mapping_iter = 1; 288 289 if (!boot_cpu_has(X86_FEATURE_PSE)) 290 use_pse = 0; 291 292 repeat: 293 pages_2m = pages_4k = 0; 294 pfn = start_pfn; 295 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 296 pgd = pgd_base + pgd_idx; 297 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 298 pmd = one_md_table_init(pgd); 299 300 if (pfn >= end_pfn) 301 continue; 302 #ifdef CONFIG_X86_PAE 303 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 304 pmd += pmd_idx; 305 #else 306 pmd_idx = 0; 307 #endif 308 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 309 pmd++, pmd_idx++) { 310 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 311 312 /* 313 * Map with big pages if possible, otherwise 314 * create normal page tables: 315 */ 316 if (use_pse) { 317 unsigned int addr2; 318 pgprot_t prot = PAGE_KERNEL_LARGE; 319 /* 320 * first pass will use the same initial 321 * identity mapping attribute + _PAGE_PSE. 322 */ 323 pgprot_t init_prot = 324 __pgprot(PTE_IDENT_ATTR | 325 _PAGE_PSE); 326 327 pfn &= PMD_MASK >> PAGE_SHIFT; 328 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 329 PAGE_OFFSET + PAGE_SIZE-1; 330 331 if (is_kernel_text(addr) || 332 is_kernel_text(addr2)) 333 prot = PAGE_KERNEL_LARGE_EXEC; 334 335 pages_2m++; 336 if (mapping_iter == 1) 337 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 338 else 339 set_pmd(pmd, pfn_pmd(pfn, prot)); 340 341 pfn += PTRS_PER_PTE; 342 continue; 343 } 344 pte = one_page_table_init(pmd); 345 346 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 347 pte += pte_ofs; 348 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 349 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 350 pgprot_t prot = PAGE_KERNEL; 351 /* 352 * first pass will use the same initial 353 * identity mapping attribute. 354 */ 355 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 356 357 if (is_kernel_text(addr)) 358 prot = PAGE_KERNEL_EXEC; 359 360 pages_4k++; 361 if (mapping_iter == 1) { 362 set_pte(pte, pfn_pte(pfn, init_prot)); 363 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 364 } else 365 set_pte(pte, pfn_pte(pfn, prot)); 366 } 367 } 368 } 369 if (mapping_iter == 1) { 370 /* 371 * update direct mapping page count only in the first 372 * iteration. 373 */ 374 update_page_count(PG_LEVEL_2M, pages_2m); 375 update_page_count(PG_LEVEL_4K, pages_4k); 376 377 /* 378 * local global flush tlb, which will flush the previous 379 * mappings present in both small and large page TLB's. 380 */ 381 __flush_tlb_all(); 382 383 /* 384 * Second iteration will set the actual desired PTE attributes. 385 */ 386 mapping_iter = 2; 387 goto repeat; 388 } 389 return last_map_addr; 390 } 391 392 pte_t *kmap_pte; 393 394 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 395 { 396 pgd_t *pgd = pgd_offset_k(vaddr); 397 p4d_t *p4d = p4d_offset(pgd, vaddr); 398 pud_t *pud = pud_offset(p4d, vaddr); 399 pmd_t *pmd = pmd_offset(pud, vaddr); 400 return pte_offset_kernel(pmd, vaddr); 401 } 402 403 static void __init kmap_init(void) 404 { 405 unsigned long kmap_vstart; 406 407 /* 408 * Cache the first kmap pte: 409 */ 410 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 411 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 412 } 413 414 #ifdef CONFIG_HIGHMEM 415 static void __init permanent_kmaps_init(pgd_t *pgd_base) 416 { 417 unsigned long vaddr; 418 pgd_t *pgd; 419 p4d_t *p4d; 420 pud_t *pud; 421 pmd_t *pmd; 422 pte_t *pte; 423 424 vaddr = PKMAP_BASE; 425 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 426 427 pgd = swapper_pg_dir + pgd_index(vaddr); 428 p4d = p4d_offset(pgd, vaddr); 429 pud = pud_offset(p4d, vaddr); 430 pmd = pmd_offset(pud, vaddr); 431 pte = pte_offset_kernel(pmd, vaddr); 432 pkmap_page_table = pte; 433 } 434 435 void __init add_highpages_with_active_regions(int nid, 436 unsigned long start_pfn, unsigned long end_pfn) 437 { 438 phys_addr_t start, end; 439 u64 i; 440 441 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 442 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 443 start_pfn, end_pfn); 444 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 445 start_pfn, end_pfn); 446 for ( ; pfn < e_pfn; pfn++) 447 if (pfn_valid(pfn)) 448 free_highmem_page(pfn_to_page(pfn)); 449 } 450 } 451 #else 452 static inline void permanent_kmaps_init(pgd_t *pgd_base) 453 { 454 } 455 #endif /* CONFIG_HIGHMEM */ 456 457 void __init sync_initial_page_table(void) 458 { 459 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 460 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 461 KERNEL_PGD_PTRS); 462 463 /* 464 * sync back low identity map too. It is used for example 465 * in the 32-bit EFI stub. 466 */ 467 clone_pgd_range(initial_page_table, 468 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 469 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 470 } 471 472 void __init native_pagetable_init(void) 473 { 474 unsigned long pfn, va; 475 pgd_t *pgd, *base = swapper_pg_dir; 476 p4d_t *p4d; 477 pud_t *pud; 478 pmd_t *pmd; 479 pte_t *pte; 480 481 /* 482 * Remove any mappings which extend past the end of physical 483 * memory from the boot time page table. 484 * In virtual address space, we should have at least two pages 485 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 486 * definition. And max_low_pfn is set to VMALLOC_END physical 487 * address. If initial memory mapping is doing right job, we 488 * should have pte used near max_low_pfn or one pmd is not present. 489 */ 490 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 491 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 492 pgd = base + pgd_index(va); 493 if (!pgd_present(*pgd)) 494 break; 495 496 p4d = p4d_offset(pgd, va); 497 pud = pud_offset(p4d, va); 498 pmd = pmd_offset(pud, va); 499 if (!pmd_present(*pmd)) 500 break; 501 502 /* should not be large page here */ 503 if (pmd_large(*pmd)) { 504 pr_warn("try to clear pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx, but pmd is big page and is not using pte !\n", 505 pfn, pmd, __pa(pmd)); 506 BUG_ON(1); 507 } 508 509 pte = pte_offset_kernel(pmd, va); 510 if (!pte_present(*pte)) 511 break; 512 513 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 514 pfn, pmd, __pa(pmd), pte, __pa(pte)); 515 pte_clear(NULL, va, pte); 516 } 517 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 518 paging_init(); 519 } 520 521 /* 522 * Build a proper pagetable for the kernel mappings. Up until this 523 * point, we've been running on some set of pagetables constructed by 524 * the boot process. 525 * 526 * If we're booting on native hardware, this will be a pagetable 527 * constructed in arch/x86/kernel/head_32.S. The root of the 528 * pagetable will be swapper_pg_dir. 529 * 530 * If we're booting paravirtualized under a hypervisor, then there are 531 * more options: we may already be running PAE, and the pagetable may 532 * or may not be based in swapper_pg_dir. In any case, 533 * paravirt_pagetable_init() will set up swapper_pg_dir 534 * appropriately for the rest of the initialization to work. 535 * 536 * In general, pagetable_init() assumes that the pagetable may already 537 * be partially populated, and so it avoids stomping on any existing 538 * mappings. 539 */ 540 void __init early_ioremap_page_table_range_init(void) 541 { 542 pgd_t *pgd_base = swapper_pg_dir; 543 unsigned long vaddr, end; 544 545 /* 546 * Fixed mappings, only the page table structure has to be 547 * created - mappings will be set by set_fixmap(): 548 */ 549 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 550 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 551 page_table_range_init(vaddr, end, pgd_base); 552 early_ioremap_reset(); 553 } 554 555 static void __init pagetable_init(void) 556 { 557 pgd_t *pgd_base = swapper_pg_dir; 558 559 permanent_kmaps_init(pgd_base); 560 } 561 562 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL) 563 /* Bits supported by the hardware: */ 564 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK; 565 /* Bits allowed in normal kernel mappings: */ 566 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK; 567 EXPORT_SYMBOL_GPL(__supported_pte_mask); 568 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */ 569 EXPORT_SYMBOL(__default_kernel_pte_mask); 570 571 /* user-defined highmem size */ 572 static unsigned int highmem_pages = -1; 573 574 /* 575 * highmem=size forces highmem to be exactly 'size' bytes. 576 * This works even on boxes that have no highmem otherwise. 577 * This also works to reduce highmem size on bigger boxes. 578 */ 579 static int __init parse_highmem(char *arg) 580 { 581 if (!arg) 582 return -EINVAL; 583 584 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 585 return 0; 586 } 587 early_param("highmem", parse_highmem); 588 589 #define MSG_HIGHMEM_TOO_BIG \ 590 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 591 592 #define MSG_LOWMEM_TOO_SMALL \ 593 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 594 /* 595 * All of RAM fits into lowmem - but if user wants highmem 596 * artificially via the highmem=x boot parameter then create 597 * it: 598 */ 599 static void __init lowmem_pfn_init(void) 600 { 601 /* max_low_pfn is 0, we already have early_res support */ 602 max_low_pfn = max_pfn; 603 604 if (highmem_pages == -1) 605 highmem_pages = 0; 606 #ifdef CONFIG_HIGHMEM 607 if (highmem_pages >= max_pfn) { 608 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 609 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 610 highmem_pages = 0; 611 } 612 if (highmem_pages) { 613 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 614 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 615 pages_to_mb(highmem_pages)); 616 highmem_pages = 0; 617 } 618 max_low_pfn -= highmem_pages; 619 } 620 #else 621 if (highmem_pages) 622 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 623 #endif 624 } 625 626 #define MSG_HIGHMEM_TOO_SMALL \ 627 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 628 629 #define MSG_HIGHMEM_TRIMMED \ 630 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 631 /* 632 * We have more RAM than fits into lowmem - we try to put it into 633 * highmem, also taking the highmem=x boot parameter into account: 634 */ 635 static void __init highmem_pfn_init(void) 636 { 637 max_low_pfn = MAXMEM_PFN; 638 639 if (highmem_pages == -1) 640 highmem_pages = max_pfn - MAXMEM_PFN; 641 642 if (highmem_pages + MAXMEM_PFN < max_pfn) 643 max_pfn = MAXMEM_PFN + highmem_pages; 644 645 if (highmem_pages + MAXMEM_PFN > max_pfn) { 646 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 647 pages_to_mb(max_pfn - MAXMEM_PFN), 648 pages_to_mb(highmem_pages)); 649 highmem_pages = 0; 650 } 651 #ifndef CONFIG_HIGHMEM 652 /* Maximum memory usable is what is directly addressable */ 653 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 654 if (max_pfn > MAX_NONPAE_PFN) 655 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 656 else 657 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 658 max_pfn = MAXMEM_PFN; 659 #else /* !CONFIG_HIGHMEM */ 660 #ifndef CONFIG_HIGHMEM64G 661 if (max_pfn > MAX_NONPAE_PFN) { 662 max_pfn = MAX_NONPAE_PFN; 663 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 664 } 665 #endif /* !CONFIG_HIGHMEM64G */ 666 #endif /* !CONFIG_HIGHMEM */ 667 } 668 669 /* 670 * Determine low and high memory ranges: 671 */ 672 void __init find_low_pfn_range(void) 673 { 674 /* it could update max_pfn */ 675 676 if (max_pfn <= MAXMEM_PFN) 677 lowmem_pfn_init(); 678 else 679 highmem_pfn_init(); 680 } 681 682 #ifndef CONFIG_NEED_MULTIPLE_NODES 683 void __init initmem_init(void) 684 { 685 #ifdef CONFIG_HIGHMEM 686 highstart_pfn = highend_pfn = max_pfn; 687 if (max_pfn > max_low_pfn) 688 highstart_pfn = max_low_pfn; 689 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 690 pages_to_mb(highend_pfn - highstart_pfn)); 691 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 692 #else 693 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 694 #endif 695 696 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); 697 sparse_memory_present_with_active_regions(0); 698 699 #ifdef CONFIG_FLATMEM 700 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 701 #endif 702 __vmalloc_start_set = true; 703 704 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 705 pages_to_mb(max_low_pfn)); 706 707 setup_bootmem_allocator(); 708 } 709 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 710 711 void __init setup_bootmem_allocator(void) 712 { 713 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 714 max_pfn_mapped<<PAGE_SHIFT); 715 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 716 } 717 718 /* 719 * paging_init() sets up the page tables - note that the first 8MB are 720 * already mapped by head.S. 721 * 722 * This routines also unmaps the page at virtual kernel address 0, so 723 * that we can trap those pesky NULL-reference errors in the kernel. 724 */ 725 void __init paging_init(void) 726 { 727 pagetable_init(); 728 729 __flush_tlb_all(); 730 731 kmap_init(); 732 733 /* 734 * NOTE: at this point the bootmem allocator is fully available. 735 */ 736 olpc_dt_build_devicetree(); 737 sparse_memory_present_with_active_regions(MAX_NUMNODES); 738 sparse_init(); 739 zone_sizes_init(); 740 } 741 742 /* 743 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 744 * and also on some strange 486's. All 586+'s are OK. This used to involve 745 * black magic jumps to work around some nasty CPU bugs, but fortunately the 746 * switch to using exceptions got rid of all that. 747 */ 748 static void __init test_wp_bit(void) 749 { 750 char z = 0; 751 752 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); 753 754 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); 755 756 if (probe_kernel_write((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { 757 clear_fixmap(FIX_WP_TEST); 758 printk(KERN_CONT "Ok.\n"); 759 return; 760 } 761 762 printk(KERN_CONT "No.\n"); 763 panic("Linux doesn't support CPUs with broken WP."); 764 } 765 766 void __init mem_init(void) 767 { 768 pci_iommu_alloc(); 769 770 #ifdef CONFIG_FLATMEM 771 BUG_ON(!mem_map); 772 #endif 773 /* 774 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 775 * be done before memblock_free_all(). Memblock use free low memory for 776 * temporary data (see find_range_array()) and for this purpose can use 777 * pages that was already passed to the buddy allocator, hence marked as 778 * not accessible in the page tables when compiled with 779 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 780 * important here. 781 */ 782 set_highmem_pages_init(); 783 784 /* this will put all low memory onto the freelists */ 785 memblock_free_all(); 786 787 after_bootmem = 1; 788 x86_init.hyper.init_after_bootmem(); 789 790 mem_init_print_info(NULL); 791 printk(KERN_INFO "virtual kernel memory layout:\n" 792 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 793 " cpu_entry : 0x%08lx - 0x%08lx (%4ld kB)\n" 794 #ifdef CONFIG_HIGHMEM 795 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 796 #endif 797 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 798 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 799 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 800 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 801 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 802 FIXADDR_START, FIXADDR_TOP, 803 (FIXADDR_TOP - FIXADDR_START) >> 10, 804 805 CPU_ENTRY_AREA_BASE, 806 CPU_ENTRY_AREA_BASE + CPU_ENTRY_AREA_MAP_SIZE, 807 CPU_ENTRY_AREA_MAP_SIZE >> 10, 808 809 #ifdef CONFIG_HIGHMEM 810 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 811 (LAST_PKMAP*PAGE_SIZE) >> 10, 812 #endif 813 814 VMALLOC_START, VMALLOC_END, 815 (VMALLOC_END - VMALLOC_START) >> 20, 816 817 (unsigned long)__va(0), (unsigned long)high_memory, 818 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 819 820 (unsigned long)&__init_begin, (unsigned long)&__init_end, 821 ((unsigned long)&__init_end - 822 (unsigned long)&__init_begin) >> 10, 823 824 (unsigned long)&_etext, (unsigned long)&_edata, 825 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 826 827 (unsigned long)&_text, (unsigned long)&_etext, 828 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 829 830 /* 831 * Check boundaries twice: Some fundamental inconsistencies can 832 * be detected at build time already. 833 */ 834 #define __FIXADDR_TOP (-PAGE_SIZE) 835 #ifdef CONFIG_HIGHMEM 836 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 837 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 838 #endif 839 #define high_memory (-128UL << 20) 840 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 841 #undef high_memory 842 #undef __FIXADDR_TOP 843 844 #ifdef CONFIG_HIGHMEM 845 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 846 BUG_ON(VMALLOC_END > PKMAP_BASE); 847 #endif 848 BUG_ON(VMALLOC_START >= VMALLOC_END); 849 BUG_ON((unsigned long)high_memory > VMALLOC_START); 850 851 test_wp_bit(); 852 } 853 854 #ifdef CONFIG_MEMORY_HOTPLUG 855 int arch_add_memory(int nid, u64 start, u64 size, 856 struct mhp_restrictions *restrictions) 857 { 858 unsigned long start_pfn = start >> PAGE_SHIFT; 859 unsigned long nr_pages = size >> PAGE_SHIFT; 860 861 return __add_pages(nid, start_pfn, nr_pages, restrictions); 862 } 863 864 void arch_remove_memory(int nid, u64 start, u64 size, 865 struct vmem_altmap *altmap) 866 { 867 unsigned long start_pfn = start >> PAGE_SHIFT; 868 unsigned long nr_pages = size >> PAGE_SHIFT; 869 870 __remove_pages(start_pfn, nr_pages, altmap); 871 } 872 #endif 873 874 int kernel_set_to_readonly __read_mostly; 875 876 void set_kernel_text_rw(void) 877 { 878 unsigned long start = PFN_ALIGN(_text); 879 unsigned long size = PFN_ALIGN(_etext) - start; 880 881 if (!kernel_set_to_readonly) 882 return; 883 884 pr_debug("Set kernel text: %lx - %lx for read write\n", 885 start, start+size); 886 887 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 888 } 889 890 void set_kernel_text_ro(void) 891 { 892 unsigned long start = PFN_ALIGN(_text); 893 unsigned long size = PFN_ALIGN(_etext) - start; 894 895 if (!kernel_set_to_readonly) 896 return; 897 898 pr_debug("Set kernel text: %lx - %lx for read only\n", 899 start, start+size); 900 901 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 902 } 903 904 static void mark_nxdata_nx(void) 905 { 906 /* 907 * When this called, init has already been executed and released, 908 * so everything past _etext should be NX. 909 */ 910 unsigned long start = PFN_ALIGN(_etext); 911 /* 912 * This comes from is_kernel_text upper limit. Also HPAGE where used: 913 */ 914 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 915 916 if (__supported_pte_mask & _PAGE_NX) 917 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 918 set_memory_nx(start, size >> PAGE_SHIFT); 919 } 920 921 void mark_rodata_ro(void) 922 { 923 unsigned long start = PFN_ALIGN(_text); 924 unsigned long size = (unsigned long)__end_rodata - start; 925 926 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 927 pr_info("Write protecting kernel text and read-only data: %luk\n", 928 size >> 10); 929 930 kernel_set_to_readonly = 1; 931 932 #ifdef CONFIG_CPA_DEBUG 933 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); 934 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 935 936 pr_info("Testing CPA: write protecting again\n"); 937 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 938 #endif 939 mark_nxdata_nx(); 940 if (__supported_pte_mask & _PAGE_NX) 941 debug_checkwx(); 942 } 943