1 /* 2 * 3 * Copyright (C) 1995 Linus Torvalds 4 * 5 * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999 6 */ 7 8 #include <linux/module.h> 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/bootmem.h> 28 #include <linux/memblock.h> 29 #include <linux/proc_fs.h> 30 #include <linux/memory_hotplug.h> 31 #include <linux/initrd.h> 32 #include <linux/cpumask.h> 33 #include <linux/gfp.h> 34 35 #include <asm/asm.h> 36 #include <asm/bios_ebda.h> 37 #include <asm/processor.h> 38 #include <asm/uaccess.h> 39 #include <asm/pgtable.h> 40 #include <asm/dma.h> 41 #include <asm/fixmap.h> 42 #include <asm/e820.h> 43 #include <asm/apic.h> 44 #include <asm/bugs.h> 45 #include <asm/tlb.h> 46 #include <asm/tlbflush.h> 47 #include <asm/olpc_ofw.h> 48 #include <asm/pgalloc.h> 49 #include <asm/sections.h> 50 #include <asm/paravirt.h> 51 #include <asm/setup.h> 52 #include <asm/cacheflush.h> 53 #include <asm/page_types.h> 54 #include <asm/init.h> 55 56 #include "mm_internal.h" 57 58 unsigned long highstart_pfn, highend_pfn; 59 60 static noinline int do_test_wp_bit(void); 61 62 bool __read_mostly __vmalloc_start_set = false; 63 64 /* 65 * Creates a middle page table and puts a pointer to it in the 66 * given global directory entry. This only returns the gd entry 67 * in non-PAE compilation mode, since the middle layer is folded. 68 */ 69 static pmd_t * __init one_md_table_init(pgd_t *pgd) 70 { 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 pud = pud_offset(pgd, 0); 80 BUG_ON(pmd_table != pmd_offset(pud, 0)); 81 82 return pmd_table; 83 } 84 #endif 85 pud = pud_offset(pgd, 0); 86 pmd_table = pmd_offset(pud, 0); 87 88 return pmd_table; 89 } 90 91 /* 92 * Create a page table and place a pointer to it in a middle page 93 * directory entry: 94 */ 95 static pte_t * __init one_page_table_init(pmd_t *pmd) 96 { 97 if (!(pmd_val(*pmd) & _PAGE_PRESENT)) { 98 pte_t *page_table = (pte_t *)alloc_low_page(); 99 100 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT); 101 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); 102 BUG_ON(page_table != pte_offset_kernel(pmd, 0)); 103 } 104 105 return pte_offset_kernel(pmd, 0); 106 } 107 108 pmd_t * __init populate_extra_pmd(unsigned long vaddr) 109 { 110 int pgd_idx = pgd_index(vaddr); 111 int pmd_idx = pmd_index(vaddr); 112 113 return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx; 114 } 115 116 pte_t * __init populate_extra_pte(unsigned long vaddr) 117 { 118 int pte_idx = pte_index(vaddr); 119 pmd_t *pmd; 120 121 pmd = populate_extra_pmd(vaddr); 122 return one_page_table_init(pmd) + pte_idx; 123 } 124 125 static unsigned long __init 126 page_table_range_init_count(unsigned long start, unsigned long end) 127 { 128 unsigned long count = 0; 129 #ifdef CONFIG_HIGHMEM 130 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 131 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 132 int pgd_idx, pmd_idx; 133 unsigned long vaddr; 134 135 if (pmd_idx_kmap_begin == pmd_idx_kmap_end) 136 return 0; 137 138 vaddr = start; 139 pgd_idx = pgd_index(vaddr); 140 pmd_idx = pmd_index(vaddr); 141 142 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) { 143 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 144 pmd_idx++) { 145 if ((vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin && 146 (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) 147 count++; 148 vaddr += PMD_SIZE; 149 } 150 pmd_idx = 0; 151 } 152 #endif 153 return count; 154 } 155 156 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd, 157 unsigned long vaddr, pte_t *lastpte, 158 void **adr) 159 { 160 #ifdef CONFIG_HIGHMEM 161 /* 162 * Something (early fixmap) may already have put a pte 163 * page here, which causes the page table allocation 164 * to become nonlinear. Attempt to fix it, and if it 165 * is still nonlinear then we have to bug. 166 */ 167 int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT; 168 int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT; 169 170 if (pmd_idx_kmap_begin != pmd_idx_kmap_end 171 && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin 172 && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end) { 173 pte_t *newpte; 174 int i; 175 176 BUG_ON(after_bootmem); 177 newpte = *adr; 178 for (i = 0; i < PTRS_PER_PTE; i++) 179 set_pte(newpte + i, pte[i]); 180 *adr = (void *)(((unsigned long)(*adr)) + PAGE_SIZE); 181 182 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT); 183 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE)); 184 BUG_ON(newpte != pte_offset_kernel(pmd, 0)); 185 __flush_tlb_all(); 186 187 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT); 188 pte = newpte; 189 } 190 BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1) 191 && vaddr > fix_to_virt(FIX_KMAP_END) 192 && lastpte && lastpte + PTRS_PER_PTE != pte); 193 #endif 194 return pte; 195 } 196 197 /* 198 * This function initializes a certain range of kernel virtual memory 199 * with new bootmem page tables, everywhere page tables are missing in 200 * the given range. 201 * 202 * NOTE: The pagetables are allocated contiguous on the physical space 203 * so we can cache the place of the first one and move around without 204 * checking the pgd every time. 205 */ 206 static void __init 207 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base) 208 { 209 int pgd_idx, pmd_idx; 210 unsigned long vaddr; 211 pgd_t *pgd; 212 pmd_t *pmd; 213 pte_t *pte = NULL; 214 unsigned long count = page_table_range_init_count(start, end); 215 void *adr = NULL; 216 217 if (count) 218 adr = alloc_low_pages(count); 219 220 vaddr = start; 221 pgd_idx = pgd_index(vaddr); 222 pmd_idx = pmd_index(vaddr); 223 pgd = pgd_base + pgd_idx; 224 225 for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) { 226 pmd = one_md_table_init(pgd); 227 pmd = pmd + pmd_index(vaddr); 228 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); 229 pmd++, pmd_idx++) { 230 pte = page_table_kmap_check(one_page_table_init(pmd), 231 pmd, vaddr, pte, &adr); 232 233 vaddr += PMD_SIZE; 234 } 235 pmd_idx = 0; 236 } 237 } 238 239 static inline int is_kernel_text(unsigned long addr) 240 { 241 if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end) 242 return 1; 243 return 0; 244 } 245 246 /* 247 * This maps the physical memory to kernel virtual address space, a total 248 * of max_low_pfn pages, by creating page tables starting from address 249 * PAGE_OFFSET: 250 */ 251 unsigned long __init 252 kernel_physical_mapping_init(unsigned long start, 253 unsigned long end, 254 unsigned long page_size_mask) 255 { 256 int use_pse = page_size_mask == (1<<PG_LEVEL_2M); 257 unsigned long last_map_addr = end; 258 unsigned long start_pfn, end_pfn; 259 pgd_t *pgd_base = swapper_pg_dir; 260 int pgd_idx, pmd_idx, pte_ofs; 261 unsigned long pfn; 262 pgd_t *pgd; 263 pmd_t *pmd; 264 pte_t *pte; 265 unsigned pages_2m, pages_4k; 266 int mapping_iter; 267 268 start_pfn = start >> PAGE_SHIFT; 269 end_pfn = end >> PAGE_SHIFT; 270 271 /* 272 * First iteration will setup identity mapping using large/small pages 273 * based on use_pse, with other attributes same as set by 274 * the early code in head_32.S 275 * 276 * Second iteration will setup the appropriate attributes (NX, GLOBAL..) 277 * as desired for the kernel identity mapping. 278 * 279 * This two pass mechanism conforms to the TLB app note which says: 280 * 281 * "Software should not write to a paging-structure entry in a way 282 * that would change, for any linear address, both the page size 283 * and either the page frame or attributes." 284 */ 285 mapping_iter = 1; 286 287 if (!cpu_has_pse) 288 use_pse = 0; 289 290 repeat: 291 pages_2m = pages_4k = 0; 292 pfn = start_pfn; 293 pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 294 pgd = pgd_base + pgd_idx; 295 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { 296 pmd = one_md_table_init(pgd); 297 298 if (pfn >= end_pfn) 299 continue; 300 #ifdef CONFIG_X86_PAE 301 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 302 pmd += pmd_idx; 303 #else 304 pmd_idx = 0; 305 #endif 306 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn; 307 pmd++, pmd_idx++) { 308 unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET; 309 310 /* 311 * Map with big pages if possible, otherwise 312 * create normal page tables: 313 */ 314 if (use_pse) { 315 unsigned int addr2; 316 pgprot_t prot = PAGE_KERNEL_LARGE; 317 /* 318 * first pass will use the same initial 319 * identity mapping attribute + _PAGE_PSE. 320 */ 321 pgprot_t init_prot = 322 __pgprot(PTE_IDENT_ATTR | 323 _PAGE_PSE); 324 325 pfn &= PMD_MASK >> PAGE_SHIFT; 326 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + 327 PAGE_OFFSET + PAGE_SIZE-1; 328 329 if (is_kernel_text(addr) || 330 is_kernel_text(addr2)) 331 prot = PAGE_KERNEL_LARGE_EXEC; 332 333 pages_2m++; 334 if (mapping_iter == 1) 335 set_pmd(pmd, pfn_pmd(pfn, init_prot)); 336 else 337 set_pmd(pmd, pfn_pmd(pfn, prot)); 338 339 pfn += PTRS_PER_PTE; 340 continue; 341 } 342 pte = one_page_table_init(pmd); 343 344 pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); 345 pte += pte_ofs; 346 for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; 347 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { 348 pgprot_t prot = PAGE_KERNEL; 349 /* 350 * first pass will use the same initial 351 * identity mapping attribute. 352 */ 353 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); 354 355 if (is_kernel_text(addr)) 356 prot = PAGE_KERNEL_EXEC; 357 358 pages_4k++; 359 if (mapping_iter == 1) { 360 set_pte(pte, pfn_pte(pfn, init_prot)); 361 last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE; 362 } else 363 set_pte(pte, pfn_pte(pfn, prot)); 364 } 365 } 366 } 367 if (mapping_iter == 1) { 368 /* 369 * update direct mapping page count only in the first 370 * iteration. 371 */ 372 update_page_count(PG_LEVEL_2M, pages_2m); 373 update_page_count(PG_LEVEL_4K, pages_4k); 374 375 /* 376 * local global flush tlb, which will flush the previous 377 * mappings present in both small and large page TLB's. 378 */ 379 __flush_tlb_all(); 380 381 /* 382 * Second iteration will set the actual desired PTE attributes. 383 */ 384 mapping_iter = 2; 385 goto repeat; 386 } 387 return last_map_addr; 388 } 389 390 pte_t *kmap_pte; 391 pgprot_t kmap_prot; 392 393 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr) 394 { 395 return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), 396 vaddr), vaddr), vaddr); 397 } 398 399 static void __init kmap_init(void) 400 { 401 unsigned long kmap_vstart; 402 403 /* 404 * Cache the first kmap pte: 405 */ 406 kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN); 407 kmap_pte = kmap_get_fixmap_pte(kmap_vstart); 408 409 kmap_prot = PAGE_KERNEL; 410 } 411 412 #ifdef CONFIG_HIGHMEM 413 static void __init permanent_kmaps_init(pgd_t *pgd_base) 414 { 415 unsigned long vaddr; 416 pgd_t *pgd; 417 pud_t *pud; 418 pmd_t *pmd; 419 pte_t *pte; 420 421 vaddr = PKMAP_BASE; 422 page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base); 423 424 pgd = swapper_pg_dir + pgd_index(vaddr); 425 pud = pud_offset(pgd, vaddr); 426 pmd = pmd_offset(pud, vaddr); 427 pte = pte_offset_kernel(pmd, vaddr); 428 pkmap_page_table = pte; 429 } 430 431 void __init add_highpages_with_active_regions(int nid, 432 unsigned long start_pfn, unsigned long end_pfn) 433 { 434 phys_addr_t start, end; 435 u64 i; 436 437 for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { 438 unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), 439 start_pfn, end_pfn); 440 unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), 441 start_pfn, end_pfn); 442 for ( ; pfn < e_pfn; pfn++) 443 if (pfn_valid(pfn)) 444 free_highmem_page(pfn_to_page(pfn)); 445 } 446 } 447 #else 448 static inline void permanent_kmaps_init(pgd_t *pgd_base) 449 { 450 } 451 #endif /* CONFIG_HIGHMEM */ 452 453 void __init native_pagetable_init(void) 454 { 455 unsigned long pfn, va; 456 pgd_t *pgd, *base = swapper_pg_dir; 457 pud_t *pud; 458 pmd_t *pmd; 459 pte_t *pte; 460 461 /* 462 * Remove any mappings which extend past the end of physical 463 * memory from the boot time page table. 464 * In virtual address space, we should have at least two pages 465 * from VMALLOC_END to pkmap or fixmap according to VMALLOC_END 466 * definition. And max_low_pfn is set to VMALLOC_END physical 467 * address. If initial memory mapping is doing right job, we 468 * should have pte used near max_low_pfn or one pmd is not present. 469 */ 470 for (pfn = max_low_pfn; pfn < 1<<(32-PAGE_SHIFT); pfn++) { 471 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT); 472 pgd = base + pgd_index(va); 473 if (!pgd_present(*pgd)) 474 break; 475 476 pud = pud_offset(pgd, va); 477 pmd = pmd_offset(pud, va); 478 if (!pmd_present(*pmd)) 479 break; 480 481 /* should not be large page here */ 482 if (pmd_large(*pmd)) { 483 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", 484 pfn, pmd, __pa(pmd)); 485 BUG_ON(1); 486 } 487 488 pte = pte_offset_kernel(pmd, va); 489 if (!pte_present(*pte)) 490 break; 491 492 printk(KERN_DEBUG "clearing pte for ram above max_low_pfn: pfn: %lx pmd: %p pmd phys: %lx pte: %p pte phys: %lx\n", 493 pfn, pmd, __pa(pmd), pte, __pa(pte)); 494 pte_clear(NULL, va, pte); 495 } 496 paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT); 497 paging_init(); 498 } 499 500 /* 501 * Build a proper pagetable for the kernel mappings. Up until this 502 * point, we've been running on some set of pagetables constructed by 503 * the boot process. 504 * 505 * If we're booting on native hardware, this will be a pagetable 506 * constructed in arch/x86/kernel/head_32.S. The root of the 507 * pagetable will be swapper_pg_dir. 508 * 509 * If we're booting paravirtualized under a hypervisor, then there are 510 * more options: we may already be running PAE, and the pagetable may 511 * or may not be based in swapper_pg_dir. In any case, 512 * paravirt_pagetable_init() will set up swapper_pg_dir 513 * appropriately for the rest of the initialization to work. 514 * 515 * In general, pagetable_init() assumes that the pagetable may already 516 * be partially populated, and so it avoids stomping on any existing 517 * mappings. 518 */ 519 void __init early_ioremap_page_table_range_init(void) 520 { 521 pgd_t *pgd_base = swapper_pg_dir; 522 unsigned long vaddr, end; 523 524 /* 525 * Fixed mappings, only the page table structure has to be 526 * created - mappings will be set by set_fixmap(): 527 */ 528 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 529 end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK; 530 page_table_range_init(vaddr, end, pgd_base); 531 early_ioremap_reset(); 532 } 533 534 static void __init pagetable_init(void) 535 { 536 pgd_t *pgd_base = swapper_pg_dir; 537 538 permanent_kmaps_init(pgd_base); 539 } 540 541 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL); 542 EXPORT_SYMBOL_GPL(__supported_pte_mask); 543 544 /* user-defined highmem size */ 545 static unsigned int highmem_pages = -1; 546 547 /* 548 * highmem=size forces highmem to be exactly 'size' bytes. 549 * This works even on boxes that have no highmem otherwise. 550 * This also works to reduce highmem size on bigger boxes. 551 */ 552 static int __init parse_highmem(char *arg) 553 { 554 if (!arg) 555 return -EINVAL; 556 557 highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; 558 return 0; 559 } 560 early_param("highmem", parse_highmem); 561 562 #define MSG_HIGHMEM_TOO_BIG \ 563 "highmem size (%luMB) is bigger than pages available (%luMB)!\n" 564 565 #define MSG_LOWMEM_TOO_SMALL \ 566 "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n" 567 /* 568 * All of RAM fits into lowmem - but if user wants highmem 569 * artificially via the highmem=x boot parameter then create 570 * it: 571 */ 572 static void __init lowmem_pfn_init(void) 573 { 574 /* max_low_pfn is 0, we already have early_res support */ 575 max_low_pfn = max_pfn; 576 577 if (highmem_pages == -1) 578 highmem_pages = 0; 579 #ifdef CONFIG_HIGHMEM 580 if (highmem_pages >= max_pfn) { 581 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG, 582 pages_to_mb(highmem_pages), pages_to_mb(max_pfn)); 583 highmem_pages = 0; 584 } 585 if (highmem_pages) { 586 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) { 587 printk(KERN_ERR MSG_LOWMEM_TOO_SMALL, 588 pages_to_mb(highmem_pages)); 589 highmem_pages = 0; 590 } 591 max_low_pfn -= highmem_pages; 592 } 593 #else 594 if (highmem_pages) 595 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n"); 596 #endif 597 } 598 599 #define MSG_HIGHMEM_TOO_SMALL \ 600 "only %luMB highmem pages available, ignoring highmem size of %luMB!\n" 601 602 #define MSG_HIGHMEM_TRIMMED \ 603 "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n" 604 /* 605 * We have more RAM than fits into lowmem - we try to put it into 606 * highmem, also taking the highmem=x boot parameter into account: 607 */ 608 static void __init highmem_pfn_init(void) 609 { 610 max_low_pfn = MAXMEM_PFN; 611 612 if (highmem_pages == -1) 613 highmem_pages = max_pfn - MAXMEM_PFN; 614 615 if (highmem_pages + MAXMEM_PFN < max_pfn) 616 max_pfn = MAXMEM_PFN + highmem_pages; 617 618 if (highmem_pages + MAXMEM_PFN > max_pfn) { 619 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL, 620 pages_to_mb(max_pfn - MAXMEM_PFN), 621 pages_to_mb(highmem_pages)); 622 highmem_pages = 0; 623 } 624 #ifndef CONFIG_HIGHMEM 625 /* Maximum memory usable is what is directly addressable */ 626 printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); 627 if (max_pfn > MAX_NONPAE_PFN) 628 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); 629 else 630 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); 631 max_pfn = MAXMEM_PFN; 632 #else /* !CONFIG_HIGHMEM */ 633 #ifndef CONFIG_HIGHMEM64G 634 if (max_pfn > MAX_NONPAE_PFN) { 635 max_pfn = MAX_NONPAE_PFN; 636 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED); 637 } 638 #endif /* !CONFIG_HIGHMEM64G */ 639 #endif /* !CONFIG_HIGHMEM */ 640 } 641 642 /* 643 * Determine low and high memory ranges: 644 */ 645 void __init find_low_pfn_range(void) 646 { 647 /* it could update max_pfn */ 648 649 if (max_pfn <= MAXMEM_PFN) 650 lowmem_pfn_init(); 651 else 652 highmem_pfn_init(); 653 } 654 655 #ifndef CONFIG_NEED_MULTIPLE_NODES 656 void __init initmem_init(void) 657 { 658 #ifdef CONFIG_HIGHMEM 659 highstart_pfn = highend_pfn = max_pfn; 660 if (max_pfn > max_low_pfn) 661 highstart_pfn = max_low_pfn; 662 printk(KERN_NOTICE "%ldMB HIGHMEM available.\n", 663 pages_to_mb(highend_pfn - highstart_pfn)); 664 high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1; 665 #else 666 high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1; 667 #endif 668 669 memblock_set_node(0, (phys_addr_t)ULLONG_MAX, &memblock.memory, 0); 670 sparse_memory_present_with_active_regions(0); 671 672 #ifdef CONFIG_FLATMEM 673 max_mapnr = IS_ENABLED(CONFIG_HIGHMEM) ? highend_pfn : max_low_pfn; 674 #endif 675 __vmalloc_start_set = true; 676 677 printk(KERN_NOTICE "%ldMB LOWMEM available.\n", 678 pages_to_mb(max_low_pfn)); 679 680 setup_bootmem_allocator(); 681 } 682 #endif /* !CONFIG_NEED_MULTIPLE_NODES */ 683 684 void __init setup_bootmem_allocator(void) 685 { 686 printk(KERN_INFO " mapped low ram: 0 - %08lx\n", 687 max_pfn_mapped<<PAGE_SHIFT); 688 printk(KERN_INFO " low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT); 689 } 690 691 /* 692 * paging_init() sets up the page tables - note that the first 8MB are 693 * already mapped by head.S. 694 * 695 * This routines also unmaps the page at virtual kernel address 0, so 696 * that we can trap those pesky NULL-reference errors in the kernel. 697 */ 698 void __init paging_init(void) 699 { 700 pagetable_init(); 701 702 __flush_tlb_all(); 703 704 kmap_init(); 705 706 /* 707 * NOTE: at this point the bootmem allocator is fully available. 708 */ 709 olpc_dt_build_devicetree(); 710 sparse_memory_present_with_active_regions(MAX_NUMNODES); 711 sparse_init(); 712 zone_sizes_init(); 713 } 714 715 /* 716 * Test if the WP bit works in supervisor mode. It isn't supported on 386's 717 * and also on some strange 486's. All 586+'s are OK. This used to involve 718 * black magic jumps to work around some nasty CPU bugs, but fortunately the 719 * switch to using exceptions got rid of all that. 720 */ 721 static void __init test_wp_bit(void) 722 { 723 printk(KERN_INFO 724 "Checking if this processor honours the WP bit even in supervisor mode..."); 725 726 /* Any page-aligned address will do, the test is non-destructive */ 727 __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_KERNEL_RO); 728 boot_cpu_data.wp_works_ok = do_test_wp_bit(); 729 clear_fixmap(FIX_WP_TEST); 730 731 if (!boot_cpu_data.wp_works_ok) { 732 printk(KERN_CONT "No.\n"); 733 panic("Linux doesn't support CPUs with broken WP."); 734 } else { 735 printk(KERN_CONT "Ok.\n"); 736 } 737 } 738 739 void __init mem_init(void) 740 { 741 pci_iommu_alloc(); 742 743 #ifdef CONFIG_FLATMEM 744 BUG_ON(!mem_map); 745 #endif 746 /* 747 * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to 748 * be done before free_all_bootmem(). Memblock use free low memory for 749 * temporary data (see find_range_array()) and for this purpose can use 750 * pages that was already passed to the buddy allocator, hence marked as 751 * not accessible in the page tables when compiled with 752 * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not 753 * important here. 754 */ 755 set_highmem_pages_init(); 756 757 /* this will put all low memory onto the freelists */ 758 free_all_bootmem(); 759 760 after_bootmem = 1; 761 762 mem_init_print_info(NULL); 763 printk(KERN_INFO "virtual kernel memory layout:\n" 764 " fixmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 765 #ifdef CONFIG_HIGHMEM 766 " pkmap : 0x%08lx - 0x%08lx (%4ld kB)\n" 767 #endif 768 " vmalloc : 0x%08lx - 0x%08lx (%4ld MB)\n" 769 " lowmem : 0x%08lx - 0x%08lx (%4ld MB)\n" 770 " .init : 0x%08lx - 0x%08lx (%4ld kB)\n" 771 " .data : 0x%08lx - 0x%08lx (%4ld kB)\n" 772 " .text : 0x%08lx - 0x%08lx (%4ld kB)\n", 773 FIXADDR_START, FIXADDR_TOP, 774 (FIXADDR_TOP - FIXADDR_START) >> 10, 775 776 #ifdef CONFIG_HIGHMEM 777 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, 778 (LAST_PKMAP*PAGE_SIZE) >> 10, 779 #endif 780 781 VMALLOC_START, VMALLOC_END, 782 (VMALLOC_END - VMALLOC_START) >> 20, 783 784 (unsigned long)__va(0), (unsigned long)high_memory, 785 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20, 786 787 (unsigned long)&__init_begin, (unsigned long)&__init_end, 788 ((unsigned long)&__init_end - 789 (unsigned long)&__init_begin) >> 10, 790 791 (unsigned long)&_etext, (unsigned long)&_edata, 792 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10, 793 794 (unsigned long)&_text, (unsigned long)&_etext, 795 ((unsigned long)&_etext - (unsigned long)&_text) >> 10); 796 797 /* 798 * Check boundaries twice: Some fundamental inconsistencies can 799 * be detected at build time already. 800 */ 801 #define __FIXADDR_TOP (-PAGE_SIZE) 802 #ifdef CONFIG_HIGHMEM 803 BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 804 BUILD_BUG_ON(VMALLOC_END > PKMAP_BASE); 805 #endif 806 #define high_memory (-128UL << 20) 807 BUILD_BUG_ON(VMALLOC_START >= VMALLOC_END); 808 #undef high_memory 809 #undef __FIXADDR_TOP 810 #ifdef CONFIG_RANDOMIZE_BASE 811 BUILD_BUG_ON(CONFIG_RANDOMIZE_BASE_MAX_OFFSET > KERNEL_IMAGE_SIZE); 812 #endif 813 814 #ifdef CONFIG_HIGHMEM 815 BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE > FIXADDR_START); 816 BUG_ON(VMALLOC_END > PKMAP_BASE); 817 #endif 818 BUG_ON(VMALLOC_START >= VMALLOC_END); 819 BUG_ON((unsigned long)high_memory > VMALLOC_START); 820 821 if (boot_cpu_data.wp_works_ok < 0) 822 test_wp_bit(); 823 } 824 825 #ifdef CONFIG_MEMORY_HOTPLUG 826 int arch_add_memory(int nid, u64 start, u64 size, bool for_device) 827 { 828 struct pglist_data *pgdata = NODE_DATA(nid); 829 struct zone *zone = pgdata->node_zones + 830 zone_for_memory(nid, start, size, ZONE_HIGHMEM, for_device); 831 unsigned long start_pfn = start >> PAGE_SHIFT; 832 unsigned long nr_pages = size >> PAGE_SHIFT; 833 834 return __add_pages(nid, zone, start_pfn, nr_pages); 835 } 836 837 #ifdef CONFIG_MEMORY_HOTREMOVE 838 int arch_remove_memory(u64 start, u64 size) 839 { 840 unsigned long start_pfn = start >> PAGE_SHIFT; 841 unsigned long nr_pages = size >> PAGE_SHIFT; 842 struct zone *zone; 843 844 zone = page_zone(pfn_to_page(start_pfn)); 845 return __remove_pages(zone, start_pfn, nr_pages); 846 } 847 #endif 848 #endif 849 850 /* 851 * This function cannot be __init, since exceptions don't work in that 852 * section. Put this after the callers, so that it cannot be inlined. 853 */ 854 static noinline int do_test_wp_bit(void) 855 { 856 char tmp_reg; 857 int flag; 858 859 __asm__ __volatile__( 860 " movb %0, %1 \n" 861 "1: movb %1, %0 \n" 862 " xorl %2, %2 \n" 863 "2: \n" 864 _ASM_EXTABLE(1b,2b) 865 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)), 866 "=q" (tmp_reg), 867 "=r" (flag) 868 :"2" (1) 869 :"memory"); 870 871 return flag; 872 } 873 874 #ifdef CONFIG_DEBUG_RODATA 875 const int rodata_test_data = 0xC3; 876 EXPORT_SYMBOL_GPL(rodata_test_data); 877 878 int kernel_set_to_readonly __read_mostly; 879 880 void set_kernel_text_rw(void) 881 { 882 unsigned long start = PFN_ALIGN(_text); 883 unsigned long size = PFN_ALIGN(_etext) - start; 884 885 if (!kernel_set_to_readonly) 886 return; 887 888 pr_debug("Set kernel text: %lx - %lx for read write\n", 889 start, start+size); 890 891 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 892 } 893 894 void set_kernel_text_ro(void) 895 { 896 unsigned long start = PFN_ALIGN(_text); 897 unsigned long size = PFN_ALIGN(_etext) - start; 898 899 if (!kernel_set_to_readonly) 900 return; 901 902 pr_debug("Set kernel text: %lx - %lx for read only\n", 903 start, start+size); 904 905 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 906 } 907 908 static void mark_nxdata_nx(void) 909 { 910 /* 911 * When this called, init has already been executed and released, 912 * so everything past _etext should be NX. 913 */ 914 unsigned long start = PFN_ALIGN(_etext); 915 /* 916 * This comes from is_kernel_text upper limit. Also HPAGE where used: 917 */ 918 unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start; 919 920 if (__supported_pte_mask & _PAGE_NX) 921 printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10); 922 set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT); 923 } 924 925 void mark_rodata_ro(void) 926 { 927 unsigned long start = PFN_ALIGN(_text); 928 unsigned long size = PFN_ALIGN(_etext) - start; 929 930 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 931 printk(KERN_INFO "Write protecting the kernel text: %luk\n", 932 size >> 10); 933 934 kernel_set_to_readonly = 1; 935 936 #ifdef CONFIG_CPA_DEBUG 937 printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n", 938 start, start+size); 939 set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT); 940 941 printk(KERN_INFO "Testing CPA: write protecting again\n"); 942 set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT); 943 #endif 944 945 start += size; 946 size = (unsigned long)__end_rodata - start; 947 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 948 printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n", 949 size >> 10); 950 rodata_test(); 951 952 #ifdef CONFIG_CPA_DEBUG 953 printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size); 954 set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT); 955 956 printk(KERN_INFO "Testing CPA: write protecting again\n"); 957 set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT); 958 #endif 959 mark_nxdata_nx(); 960 if (__supported_pte_mask & _PAGE_NX) 961 debug_checkwx(); 962 } 963 #endif 964 965