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/dma.h> 39 #include <asm/fixmap.h> 40 #include <asm/e820/api.h> 41 #include <asm/apic.h> 42 #include <asm/bugs.h> 43 #include <asm/tlb.h> 44 #include <asm/tlbflush.h> 45 #include <asm/olpc_ofw.h> 46 #include <asm/pgalloc.h> 47 #include <asm/sections.h> 48 #include <asm/paravirt.h> 49 #include <asm/setup.h> 50 #include <asm/set_memory.h> 51 #include <asm/page_types.h> 52 #include <asm/cpu_entry_area.h> 53 #include <asm/init.h> 54 #include <asm/pgtable_areas.h> 55 #include <asm/numa.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_x86_32_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 pgprot_t prot) 258 { 259 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 260 unsigned long last_map_addr = end; 261 unsigned long start_pfn, end_pfn; 262 pgd_t *pgd_base = swapper_pg_dir; 263 int pgd_idx, pmd_idx, pte_ofs; 264 unsigned long pfn; 265 pgd_t *pgd; 266 pmd_t *pmd; 267 pte_t *pte; 268 unsigned pages_2m, pages_4k; 269 int mapping_iter; 270 271 start_pfn = start >> PAGE_SHIFT; 272 end_pfn = end >> PAGE_SHIFT; 273 274 /* 275 * First iteration will setup identity mapping using large/small pages 276 * based on use_pse, with other attributes same as set by 277 * the early code in head_32.S 278 * 279 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 280 * as desired for the kernel identity mapping. 281 * 282 * This two pass mechanism conforms to the TLB app note which says: 283 * 284 * "Software should not write to a paging-structure entry in a way 285 * that would change, for any linear address, both the page size 286 * and either the page frame or attributes." 287 */ 288 mapping_iter = 1; 289 290 if (!boot_cpu_has(X86_FEATURE_PSE)) 291 use_pse = 0; 292 293 repeat: 294 pages_2m = pages_4k = 0; 295 pfn = start_pfn; 296 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 297 pgd = pgd_base + pgd_idx; 298 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 299 pmd = one_md_table_init(pgd); 300 301 if (pfn >= end_pfn) 302 continue; 303 #ifdef CONFIG_X86_PAE 304 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 305 pmd += pmd_idx; 306 #else 307 pmd_idx = 0; 308 #endif 309 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 310 pmd++, pmd_idx++) { 311 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 312 313 /* 314 * Map with big pages if possible, otherwise 315 * create normal page tables: 316 */ 317 if (use_pse) { 318 unsigned int addr2; 319 pgprot_t prot = PAGE_KERNEL_LARGE; 320 /* 321 * first pass will use the same initial 322 * identity mapping attribute + _PAGE_PSE. 323 */ 324 pgprot_t init_prot = 325 __pgprot(PTE_IDENT_ATTR | 326 _PAGE_PSE); 327 328 pfn &= PMD_MASK >> PAGE_SHIFT; 329 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 330 PAGE_OFFSET + PAGE_SIZE-1; 331 332 if (is_x86_32_kernel_text(addr) || 333 is_x86_32_kernel_text(addr2)) 334 prot = PAGE_KERNEL_LARGE_EXEC; 335 336 pages_2m++; 337 if (mapping_iter == 1) 338 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 339 else 340 set_pmd(pmd, pfn_pmd(pfn, prot)); 341 342 pfn += PTRS_PER_PTE; 343 continue; 344 } 345 pte = one_page_table_init(pmd); 346 347 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 348 pte += pte_ofs; 349 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 350 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 351 pgprot_t prot = PAGE_KERNEL; 352 /* 353 * first pass will use the same initial 354 * identity mapping attribute. 355 */ 356 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 357 358 if (is_x86_32_kernel_text(addr)) 359 prot = PAGE_KERNEL_EXEC; 360 361 pages_4k++; 362 if (mapping_iter == 1) { 363 set_pte(pte, pfn_pte(pfn, init_prot)); 364 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 365 } else 366 set_pte(pte, pfn_pte(pfn, prot)); 367 } 368 } 369 } 370 if (mapping_iter == 1) { 371 /* 372 * update direct mapping page count only in the first 373 * iteration. 374 */ 375 update_page_count(PG_LEVEL_2M, pages_2m); 376 update_page_count(PG_LEVEL_4K, pages_4k); 377 378 /* 379 * local global flush tlb, which will flush the previous 380 * mappings present in both small and large page TLB's. 381 */ 382 __flush_tlb_all(); 383 384 /* 385 * Second iteration will set the actual desired PTE attributes. 386 */ 387 mapping_iter = 2; 388 goto repeat; 389 } 390 return last_map_addr; 391 } 392 393 #ifdef CONFIG_HIGHMEM 394 static void __init permanent_kmaps_init(pgd_t *pgd_base) 395 { 396 unsigned long vaddr = PKMAP_BASE; 397 398 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 399 400 pkmap_page_table = virt_to_kpte(vaddr); 401 } 402 403 void __init add_highpages_with_active_regions(int nid, 404 unsigned long start_pfn, unsigned long end_pfn) 405 { 406 phys_addr_t start, end; 407 u64 i; 408 409 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 410 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 411 start_pfn, end_pfn); 412 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 413 start_pfn, end_pfn); 414 for ( ; pfn < e_pfn; pfn++) 415 if (pfn_valid(pfn)) 416 free_highmem_page(pfn_to_page(pfn)); 417 } 418 } 419 #else 420 static inline void permanent_kmaps_init(pgd_t *pgd_base) 421 { 422 } 423 #endif /* CONFIG_HIGHMEM */ 424 425 void __init sync_initial_page_table(void) 426 { 427 clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY, 428 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 429 KERNEL_PGD_PTRS); 430 431 /* 432 * sync back low identity map too. It is used for example 433 * in the 32-bit EFI stub. 434 */ 435 clone_pgd_range(initial_page_table, 436 swapper_pg_dir + KERNEL_PGD_BOUNDARY, 437 min(KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY)); 438 } 439 440 void __init native_pagetable_init(void) 441 { 442 unsigned long pfn, va; 443 pgd_t *pgd, *base = swapper_pg_dir; 444 p4d_t *p4d; 445 pud_t *pud; 446 pmd_t *pmd; 447 pte_t *pte; 448 449 /* 450 * Remove any mappings which extend past the end of physical 451 * memory from the boot time page table. 452 * In virtual address space, we should have at least two pages 453 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 454 * definition. And max_low_pfn is set to VMALLOC_END physical 455 * address. If initial memory mapping is doing right job, we 456 * should have pte used near max_low_pfn or one pmd is not present. 457 */ 458 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 459 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 460 pgd = base + pgd_index(va); 461 if (!pgd_present(*pgd)) 462 break; 463 464 p4d = p4d_offset(pgd, va); 465 pud = pud_offset(p4d, va); 466 pmd = pmd_offset(pud, va); 467 if (!pmd_present(*pmd)) 468 break; 469 470 /* should not be large page here */ 471 if (pmd_large(*pmd)) { 472 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", 473 pfn, pmd, __pa(pmd)); 474 BUG_ON(1); 475 } 476 477 pte = pte_offset_kernel(pmd, va); 478 if (!pte_present(*pte)) 479 break; 480 481 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 482 pfn, pmd, __pa(pmd), pte, __pa(pte)); 483 pte_clear(NULL, va, pte); 484 } 485 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 486 paging_init(); 487 } 488 489 /* 490 * Build a proper pagetable for the kernel mappings. Up until this 491 * point, we've been running on some set of pagetables constructed by 492 * the boot process. 493 * 494 * If we're booting on native hardware, this will be a pagetable 495 * constructed in arch/x86/kernel/head_32.S. The root of the 496 * pagetable will be swapper_pg_dir. 497 * 498 * If we're booting paravirtualized under a hypervisor, then there are 499 * more options: we may already be running PAE, and the pagetable may 500 * or may not be based in swapper_pg_dir. In any case, 501 * paravirt_pagetable_init() will set up swapper_pg_dir 502 * appropriately for the rest of the initialization to work. 503 * 504 * In general, pagetable_init() assumes that the pagetable may already 505 * be partially populated, and so it avoids stomping on any existing 506 * mappings. 507 */ 508 void __init early_ioremap_page_table_range_init(void) 509 { 510 pgd_t *pgd_base = swapper_pg_dir; 511 unsigned long vaddr, end; 512 513 /* 514 * Fixed mappings, only the page table structure has to be 515 * created - mappings will be set by set_fixmap(): 516 */ 517 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 518 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 519 page_table_range_init(vaddr, end, pgd_base); 520 early_ioremap_reset(); 521 } 522 523 static void __init pagetable_init(void) 524 { 525 pgd_t *pgd_base = swapper_pg_dir; 526 527 permanent_kmaps_init(pgd_base); 528 } 529 530 #define DEFAULT_PTE_MASK ~(_PAGE_NX | _PAGE_GLOBAL) 531 /* Bits supported by the hardware: */ 532 pteval_t __supported_pte_mask __read_mostly = DEFAULT_PTE_MASK; 533 /* Bits allowed in normal kernel mappings: */ 534 pteval_t __default_kernel_pte_mask __read_mostly = DEFAULT_PTE_MASK; 535 EXPORT_SYMBOL_GPL(__supported_pte_mask); 536 /* Used in PAGE_KERNEL_* macros which are reasonably used out-of-tree: */ 537 EXPORT_SYMBOL(__default_kernel_pte_mask); 538 539 /* user-defined highmem size */ 540 static unsigned int highmem_pages = -1; 541 542 /* 543 * highmem=size forces highmem to be exactly 'size' bytes. 544 * This works even on boxes that have no highmem otherwise. 545 * This also works to reduce highmem size on bigger boxes. 546 */ 547 static int __init parse_highmem(char *arg) 548 { 549 if (!arg) 550 return -EINVAL; 551 552 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 553 return 0; 554 } 555 early_param("highmem", parse_highmem); 556 557 #define MSG_HIGHMEM_TOO_BIG \ 558 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 559 560 #define MSG_LOWMEM_TOO_SMALL \ 561 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 562 /* 563 * All of RAM fits into lowmem - but if user wants highmem 564 * artificially via the highmem=x boot parameter then create 565 * it: 566 */ 567 static void __init lowmem_pfn_init(void) 568 { 569 /* max_low_pfn is 0, we already have early_res support */ 570 max_low_pfn = max_pfn; 571 572 if (highmem_pages == -1) 573 highmem_pages = 0; 574 #ifdef CONFIG_HIGHMEM 575 if (highmem_pages >= max_pfn) { 576 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 577 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 578 highmem_pages = 0; 579 } 580 if (highmem_pages) { 581 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 582 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 583 pages_to_mb(highmem_pages)); 584 highmem_pages = 0; 585 } 586 max_low_pfn -= highmem_pages; 587 } 588 #else 589 if (highmem_pages) 590 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 591 #endif 592 } 593 594 #define MSG_HIGHMEM_TOO_SMALL \ 595 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 596 597 #define MSG_HIGHMEM_TRIMMED \ 598 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 599 /* 600 * We have more RAM than fits into lowmem - we try to put it into 601 * highmem, also taking the highmem=x boot parameter into account: 602 */ 603 static void __init highmem_pfn_init(void) 604 { 605 max_low_pfn = MAXMEM_PFN; 606 607 if (highmem_pages == -1) 608 highmem_pages = max_pfn - MAXMEM_PFN; 609 610 if (highmem_pages + MAXMEM_PFN < max_pfn) 611 max_pfn = MAXMEM_PFN + highmem_pages; 612 613 if (highmem_pages + MAXMEM_PFN > max_pfn) { 614 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 615 pages_to_mb(max_pfn - MAXMEM_PFN), 616 pages_to_mb(highmem_pages)); 617 highmem_pages = 0; 618 } 619 #ifndef CONFIG_HIGHMEM 620 /* Maximum memory usable is what is directly addressable */ 621 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 622 if (max_pfn > MAX_NONPAE_PFN) 623 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 624 else 625 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 626 max_pfn = MAXMEM_PFN; 627 #else /* !CONFIG_HIGHMEM */ 628 #ifndef CONFIG_HIGHMEM64G 629 if (max_pfn > MAX_NONPAE_PFN) { 630 max_pfn = MAX_NONPAE_PFN; 631 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 632 } 633 #endif /* !CONFIG_HIGHMEM64G */ 634 #endif /* !CONFIG_HIGHMEM */ 635 } 636 637 /* 638 * Determine low and high memory ranges: 639 */ 640 void __init find_low_pfn_range(void) 641 { 642 /* it could update max_pfn */ 643 644 if (max_pfn <= MAXMEM_PFN) 645 lowmem_pfn_init(); 646 else 647 highmem_pfn_init(); 648 } 649 650 #ifndef CONFIG_NUMA 651 void __init initmem_init(void) 652 { 653 #ifdef CONFIG_HIGHMEM 654 highstart_pfn = highend_pfn = max_pfn; 655 if (max_pfn > max_low_pfn) 656 highstart_pfn = max_low_pfn; 657 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 658 pages_to_mb(highend_pfn - highstart_pfn)); 659 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 660 #else 661 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 662 #endif 663 664 memblock_set_node(0, PHYS_ADDR_MAX, &memblock.memory, 0); 665 666 #ifdef CONFIG_FLATMEM 667 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 668 #endif 669 __vmalloc_start_set = true; 670 671 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 672 pages_to_mb(max_low_pfn)); 673 674 setup_bootmem_allocator(); 675 } 676 #endif /* !CONFIG_NUMA */ 677 678 void __init setup_bootmem_allocator(void) 679 { 680 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 681 max_pfn_mapped<<PAGE_SHIFT); 682 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 683 } 684 685 /* 686 * paging_init() sets up the page tables - note that the first 8MB are 687 * already mapped by head.S. 688 * 689 * This routines also unmaps the page at virtual kernel address 0, so 690 * that we can trap those pesky NULL-reference errors in the kernel. 691 */ 692 void __init paging_init(void) 693 { 694 pagetable_init(); 695 696 __flush_tlb_all(); 697 698 /* 699 * NOTE: at this point the bootmem allocator is fully available. 700 */ 701 olpc_dt_build_devicetree(); 702 sparse_init(); 703 zone_sizes_init(); 704 } 705 706 /* 707 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 708 * and also on some strange 486's. All 586+'s are OK. This used to involve 709 * black magic jumps to work around some nasty CPU bugs, but fortunately the 710 * switch to using exceptions got rid of all that. 711 */ 712 static void __init test_wp_bit(void) 713 { 714 char z = 0; 715 716 printk(KERN_INFO "Checking if this processor honours the WP bit even in supervisor mode..."); 717 718 __set_fixmap(FIX_WP_TEST, __pa_symbol(empty_zero_page), PAGE_KERNEL_RO); 719 720 if (copy_to_kernel_nofault((char *)fix_to_virt(FIX_WP_TEST), &z, 1)) { 721 clear_fixmap(FIX_WP_TEST); 722 printk(KERN_CONT "Ok.\n"); 723 return; 724 } 725 726 printk(KERN_CONT "No.\n"); 727 panic("Linux doesn't support CPUs with broken WP."); 728 } 729 730 void __init mem_init(void) 731 { 732 pci_iommu_alloc(); 733 734 #ifdef CONFIG_FLATMEM 735 BUG_ON(!mem_map); 736 #endif 737 /* 738 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 739 * be done before memblock_free_all(). Memblock use free low memory for 740 * temporary data (see find_range_array()) and for this purpose can use 741 * pages that was already passed to the buddy allocator, hence marked as 742 * not accessible in the page tables when compiled with 743 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 744 * important here. 745 */ 746 set_highmem_pages_init(); 747 748 /* this will put all low memory onto the freelists */ 749 memblock_free_all(); 750 751 after_bootmem = 1; 752 x86_init.hyper.init_after_bootmem(); 753 754 /* 755 * Check boundaries twice: Some fundamental inconsistencies can 756 * be detected at build time already. 757 */ 758 #define __FIXADDR_TOP (-PAGE_SIZE) 759 #ifdef CONFIG_HIGHMEM 760 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 761 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 762 #endif 763 #define high_memory (-128UL << 20) 764 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 765 #undef high_memory 766 #undef __FIXADDR_TOP 767 768 #ifdef CONFIG_HIGHMEM 769 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 770 BUG_ON(VMALLOC_END > PKMAP_BASE); 771 #endif 772 BUG_ON(VMALLOC_START >= VMALLOC_END); 773 BUG_ON((unsigned long)high_memory > VMALLOC_START); 774 775 test_wp_bit(); 776 } 777 778 int kernel_set_to_readonly __read_mostly; 779 780 static void mark_nxdata_nx(void) 781 { 782 /* 783 * When this called, init has already been executed and released, 784 * so everything past _etext should be NX. 785 */ 786 unsigned long start = PFN_ALIGN(_etext); 787 /* 788 * This comes from is_x86_32_kernel_text upper limit. Also HPAGE where used: 789 */ 790 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 791 792 if (__supported_pte_mask & _PAGE_NX) 793 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 794 set_memory_nx(start, size >> PAGE_SHIFT); 795 } 796 797 void mark_rodata_ro(void) 798 { 799 unsigned long start = PFN_ALIGN(_text); 800 unsigned long size = (unsigned long)__end_rodata - start; 801 802 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 803 pr_info("Write protecting kernel text and read-only data: %luk\n", 804 size >> 10); 805 806 kernel_set_to_readonly = 1; 807 808 #ifdef CONFIG_CPA_DEBUG 809 pr_info("Testing CPA: Reverting %lx-%lx\n", start, start + size); 810 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 811 812 pr_info("Testing CPA: write protecting again\n"); 813 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 814 #endif 815 mark_nxdata_nx(); 816 if (__supported_pte_mask & _PAGE_NX) 817 debug_checkwx(); 818 } 819