arch/x86/mm/init_32.c

   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/pfn.h>
  25 #include <linux/poison.h>
  26 #include <linux/bootmem.h>
  27 #include <linux/slab.h>
  28 #include <linux/proc_fs.h>
  29 #include <linux/memory_hotplug.h>
  30 #include <linux/initrd.h>
  31 #include <linux/cpumask.h>
  32
  33 #include <asm/asm.h>
  34 #include <asm/bios_ebda.h>
  35 #include <asm/processor.h>
  36 #include <asm/system.h>
  37 #include <asm/uaccess.h>
  38 #include <asm/pgtable.h>
  39 #include <asm/dma.h>
  40 #include <asm/fixmap.h>
  41 #include <asm/e820.h>
  42 #include <asm/apic.h>
  43 #include <asm/bugs.h>
  44 #include <asm/tlb.h>
  45 #include <asm/tlbflush.h>
  46 #include <asm/pgalloc.h>
  47 #include <asm/sections.h>
  48 #include <asm/paravirt.h>
  49 #include <asm/setup.h>
  50 #include <asm/cacheflush.h>
  51 #include <asm/smp.h>
  52
  53 unsigned int __VMALLOC_RESERVE = 128 << 20;
  54
  55 unsigned long max_low_pfn_mapped;
  56 unsigned long max_pfn_mapped;
  57
  58 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  59 unsigned long highstart_pfn, highend_pfn;
  60
  61 static noinline int do_test_wp_bit(void);
  62
  63
  64 static unsigned long __initdata table_start;
  65 static unsigned long __meminitdata table_end;
  66 static unsigned long __meminitdata table_top;
  67
  68 static int __initdata after_init_bootmem;
  69
  70 static __init void *alloc_low_page(unsigned long *phys)
  71 {
  72         unsigned long pfn = table_end++;
  73         void *adr;
  74
  75         if (pfn >= table_top)
  76                 panic("alloc_low_page: ran out of memory");
  77
  78         adr = __va(pfn * PAGE_SIZE);
  79         memset(adr, 0, PAGE_SIZE);
  80         *phys  = pfn * PAGE_SIZE;
  81         return adr;
  82 }
  83
  84 /*
  85  * Creates a middle page table and puts a pointer to it in the
  86  * given global directory entry. This only returns the gd entry
  87  * in non-PAE compilation mode, since the middle layer is folded.
  88  */
  89 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  90 {
  91         pud_t *pud;
  92         pmd_t *pmd_table;
  93
  94 #ifdef CONFIG_X86_PAE
  95         unsigned long phys;
  96         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  97                 if (after_init_bootmem)
  98                         pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  99                 else
 100                         pmd_table = (pmd_t *)alloc_low_page(&phys);
 101                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
 102                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
 103                 pud = pud_offset(pgd, 0);
 104                 BUG_ON(pmd_table != pmd_offset(pud, 0));
 105         }
 106 #endif
 107         pud = pud_offset(pgd, 0);
 108         pmd_table = pmd_offset(pud, 0);
 109
 110         return pmd_table;
 111 }
 112
 113 /*
 114  * Create a page table and place a pointer to it in a middle page
 115  * directory entry:
 116  */
 117 static pte_t * __init one_page_table_init(pmd_t *pmd)
 118 {
 119         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 120                 pte_t *page_table = NULL;
 121
 122                 if (after_init_bootmem) {
 123 #ifdef CONFIG_DEBUG_PAGEALLOC
 124                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 125 #endif
 126                         if (!page_table)
 127                                 page_table =
 128                                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 129                 } else {
 130                         unsigned long phys;
 131                         page_table = (pte_t *)alloc_low_page(&phys);
 132                 }
 133
 134                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 135                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 136                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 137         }
 138
 139         return pte_offset_kernel(pmd, 0);
 140 }
 141
 142 /*
 143  * This function initializes a certain range of kernel virtual memory
 144  * with new bootmem page tables, everywhere page tables are missing in
 145  * the given range.
 146  *
 147  * NOTE: The pagetables are allocated contiguous on the physical space
 148  * so we can cache the place of the first one and move around without
 149  * checking the pgd every time.
 150  */
 151 static void __init
 152 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 153 {
 154         int pgd_idx, pmd_idx;
 155         unsigned long vaddr;
 156         pgd_t *pgd;
 157         pmd_t *pmd;
 158
 159         vaddr = start;
 160         pgd_idx = pgd_index(vaddr);
 161         pmd_idx = pmd_index(vaddr);
 162         pgd = pgd_base + pgd_idx;
 163
 164         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 165                 pmd = one_md_table_init(pgd);
 166                 pmd = pmd + pmd_index(vaddr);
 167                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 168                                                         pmd++, pmd_idx++) {
 169                         one_page_table_init(pmd);
 170
 171                         vaddr += PMD_SIZE;
 172                 }
 173                 pmd_idx = 0;
 174         }
 175 }
 176
 177 static inline int is_kernel_text(unsigned long addr)
 178 {
 179         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 180                 return 1;
 181         return 0;
 182 }
 183
 184 /*
 185  * This maps the physical memory to kernel virtual address space, a total
 186  * of max_low_pfn pages, by creating page tables starting from address
 187  * PAGE_OFFSET:
 188  */
 189 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
 190                                                 unsigned long start_pfn,
 191                                                 unsigned long end_pfn,
 192                                                 int use_pse)
 193 {
 194         int pgd_idx, pmd_idx, pte_ofs;
 195         unsigned long pfn;
 196         pgd_t *pgd;
 197         pmd_t *pmd;
 198         pte_t *pte;
 199         unsigned pages_2m, pages_4k;
 200         int mapping_iter;
 201
 202         /*
 203          * First iteration will setup identity mapping using large/small pages
 204          * based on use_pse, with other attributes same as set by
 205          * the early code in head_32.S
 206          *
 207          * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
 208          * as desired for the kernel identity mapping.
 209          *
 210          * This two pass mechanism conforms to the TLB app note which says:
 211          *
 212          *     "Software should not write to a paging-structure entry in a way
 213          *      that would change, for any linear address, both the page size
 214          *      and either the page frame or attributes."
 215          */
 216         mapping_iter = 1;
 217
 218         if (!cpu_has_pse)
 219                 use_pse = 0;
 220
 221 repeat:
 222         pages_2m = pages_4k = 0;
 223         pfn = start_pfn;
 224         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 225         pgd = pgd_base + pgd_idx;
 226         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 227                 pmd = one_md_table_init(pgd);
 228
 229                 if (pfn >= end_pfn)
 230                         continue;
 231 #ifdef CONFIG_X86_PAE
 232                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 233                 pmd += pmd_idx;
 234 #else
 235                 pmd_idx = 0;
 236 #endif
 237                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 238                      pmd++, pmd_idx++) {
 239                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 240
 241                         /*
 242                          * Map with big pages if possible, otherwise
 243                          * create normal page tables:
 244                          */
 245                         if (use_pse) {
 246                                 unsigned int addr2;
 247                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 248                                 /*
 249                                  * first pass will use the same initial
 250                                  * identity mapping attribute + _PAGE_PSE.
 251                                  */
 252                                 pgprot_t init_prot =
 253                                         __pgprot(PTE_IDENT_ATTR |
 254                                                  _PAGE_PSE);
 255
 256                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 257                                         PAGE_OFFSET + PAGE_SIZE-1;
 258
 259                                 if (is_kernel_text(addr) ||
 260                                     is_kernel_text(addr2))
 261                                         prot = PAGE_KERNEL_LARGE_EXEC;
 262
 263                                 pages_2m++;
 264                                 if (mapping_iter == 1)
 265                                         set_pmd(pmd, pfn_pmd(pfn, init_prot));
 266                                 else
 267                                         set_pmd(pmd, pfn_pmd(pfn, prot));
 268
 269                                 pfn += PTRS_PER_PTE;
 270                                 continue;
 271                         }
 272                         pte = one_page_table_init(pmd);
 273
 274                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 275                         pte += pte_ofs;
 276                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 277                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 278                                 pgprot_t prot = PAGE_KERNEL;
 279                                 /*
 280                                  * first pass will use the same initial
 281                                  * identity mapping attribute.
 282                                  */
 283                                 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 284
 285                                 if (is_kernel_text(addr))
 286                                         prot = PAGE_KERNEL_EXEC;
 287
 288                                 pages_4k++;
 289                                 if (mapping_iter == 1)
 290                                         set_pte(pte, pfn_pte(pfn, init_prot));
 291                                 else
 292                                         set_pte(pte, pfn_pte(pfn, prot));
 293                         }
 294                 }
 295         }
 296         if (mapping_iter == 1) {
 297                 /*
 298                  * update direct mapping page count only in the first
 299                  * iteration.
 300                  */
 301                 update_page_count(PG_LEVEL_2M, pages_2m);
 302                 update_page_count(PG_LEVEL_4K, pages_4k);
 303
 304                 /*
 305                  * local global flush tlb, which will flush the previous
 306                  * mappings present in both small and large page TLB's.
 307                  */
 308                 __flush_tlb_all();
 309
 310                 /*
 311                  * Second iteration will set the actual desired PTE attributes.
 312                  */
 313                 mapping_iter = 2;
 314                 goto repeat;
 315         }
 316 }
 317
 318 /*
 319  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 320  * is valid. The argument is a physical page number.
 321  *
 322  *
 323  * On x86, access has to be given to the first megabyte of ram because that area
 324  * contains bios code and data regions used by X and dosemu and similar apps.
 325  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 326  * mmio resources as well as potential bios/acpi data regions.
 327  */
 328 int devmem_is_allowed(unsigned long pagenr)
 329 {
 330         if (pagenr <= 256)
 331                 return 1;
 332         if (!page_is_ram(pagenr))
 333                 return 1;
 334         return 0;
 335 }
 336
 337 #ifdef CONFIG_HIGHMEM
 338 pte_t *kmap_pte;
 339 pgprot_t kmap_prot;
 340
 341 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 342 {
 343         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 344                         vaddr), vaddr), vaddr);
 345 }
 346
 347 static void __init kmap_init(void)
 348 {
 349         unsigned long kmap_vstart;
 350
 351         /*
 352          * Cache the first kmap pte:
 353          */
 354         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 355         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 356
 357         kmap_prot = PAGE_KERNEL;
 358 }
 359
 360 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 361 {
 362         unsigned long vaddr;
 363         pgd_t *pgd;
 364         pud_t *pud;
 365         pmd_t *pmd;
 366         pte_t *pte;
 367
 368         vaddr = PKMAP_BASE;
 369         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 370
 371         pgd = swapper_pg_dir + pgd_index(vaddr);
 372         pud = pud_offset(pgd, vaddr);
 373         pmd = pmd_offset(pud, vaddr);
 374         pte = pte_offset_kernel(pmd, vaddr);
 375         pkmap_page_table = pte;
 376 }
 377
 378 static void __init add_one_highpage_init(struct page *page, int pfn)
 379 {
 380         ClearPageReserved(page);
 381         init_page_count(page);
 382         __free_page(page);
 383         totalhigh_pages++;
 384 }
 385
 386 struct add_highpages_data {
 387         unsigned long start_pfn;
 388         unsigned long end_pfn;
 389 };
 390
 391 static int __init add_highpages_work_fn(unsigned long start_pfn,
 392                                          unsigned long end_pfn, void *datax)
 393 {
 394         int node_pfn;
 395         struct page *page;
 396         unsigned long final_start_pfn, final_end_pfn;
 397         struct add_highpages_data *data;
 398
 399         data = (struct add_highpages_data *)datax;
 400
 401         final_start_pfn = max(start_pfn, data->start_pfn);
 402         final_end_pfn = min(end_pfn, data->end_pfn);
 403         if (final_start_pfn >= final_end_pfn)
 404                 return 0;
 405
 406         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 407              node_pfn++) {
 408                 if (!pfn_valid(node_pfn))
 409                         continue;
 410                 page = pfn_to_page(node_pfn);
 411                 add_one_highpage_init(page, node_pfn);
 412         }
 413
 414         return 0;
 415
 416 }
 417
 418 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 419                                               unsigned long end_pfn)
 420 {
 421         struct add_highpages_data data;
 422
 423         data.start_pfn = start_pfn;
 424         data.end_pfn = end_pfn;
 425
 426         work_with_active_regions(nid, add_highpages_work_fn, &data);
 427 }
 428
 429 #ifndef CONFIG_NUMA
 430 static void __init set_highmem_pages_init(void)
 431 {
 432         add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
 433
 434         totalram_pages += totalhigh_pages;
 435 }
 436 #endif /* !CONFIG_NUMA */
 437
 438 #else
 439 # define kmap_init()                            do { } while (0)
 440 # define permanent_kmaps_init(pgd_base)         do { } while (0)
 441 # define set_highmem_pages_init()       do { } while (0)
 442 #endif /* CONFIG_HIGHMEM */
 443
 444 void __init native_pagetable_setup_start(pgd_t *base)
 445 {
 446         unsigned long pfn, va;
 447         pgd_t *pgd;
 448         pud_t *pud;
 449         pmd_t *pmd;
 450         pte_t *pte;
 451
 452         /*
 453          * Remove any mappings which extend past the end of physical
 454          * memory from the boot time page table:
 455          */
 456         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 457                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 458                 pgd = base + pgd_index(va);
 459                 if (!pgd_present(*pgd))
 460                         break;
 461
 462                 pud = pud_offset(pgd, va);
 463                 pmd = pmd_offset(pud, va);
 464                 if (!pmd_present(*pmd))
 465                         break;
 466
 467                 pte = pte_offset_kernel(pmd, va);
 468                 if (!pte_present(*pte))
 469                         break;
 470
 471                 pte_clear(NULL, va, pte);
 472         }
 473         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 474 }
 475
 476 void __init native_pagetable_setup_done(pgd_t *base)
 477 {
 478 }
 479
 480 /*
 481  * Build a proper pagetable for the kernel mappings.  Up until this
 482  * point, we've been running on some set of pagetables constructed by
 483  * the boot process.
 484  *
 485  * If we're booting on native hardware, this will be a pagetable
 486  * constructed in arch/x86/kernel/head_32.S.  The root of the
 487  * pagetable will be swapper_pg_dir.
 488  *
 489  * If we're booting paravirtualized under a hypervisor, then there are
 490  * more options: we may already be running PAE, and the pagetable may
 491  * or may not be based in swapper_pg_dir.  In any case,
 492  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 493  * appropriately for the rest of the initialization to work.
 494  *
 495  * In general, pagetable_init() assumes that the pagetable may already
 496  * be partially populated, and so it avoids stomping on any existing
 497  * mappings.
 498  */
 499 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
 500 {
 501         unsigned long vaddr, end;
 502
 503         /*
 504          * Fixed mappings, only the page table structure has to be
 505          * created - mappings will be set by set_fixmap():
 506          */
 507         early_ioremap_clear();
 508         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 509         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 510         page_table_range_init(vaddr, end, pgd_base);
 511         early_ioremap_reset();
 512 }
 513
 514 static void __init pagetable_init(void)
 515 {
 516         pgd_t *pgd_base = swapper_pg_dir;
 517
 518         permanent_kmaps_init(pgd_base);
 519 }
 520
 521 #ifdef CONFIG_ACPI_SLEEP
 522 /*
 523  * ACPI suspend needs this for resume, because things like the intel-agp
 524  * driver might have split up a kernel 4MB mapping.
 525  */
 526 char swsusp_pg_dir[PAGE_SIZE]
 527         __attribute__ ((aligned(PAGE_SIZE)));
 528
 529 static inline void save_pg_dir(void)
 530 {
 531         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 532 }
 533 #else /* !CONFIG_ACPI_SLEEP */
 534 static inline void save_pg_dir(void)
 535 {
 536 }
 537 #endif /* !CONFIG_ACPI_SLEEP */
 538
 539 void zap_low_mappings(void)
 540 {
 541         int i;
 542
 543         /*
 544          * Zap initial low-memory mappings.
 545          *
 546          * Note that "pgd_clear()" doesn't do it for
 547          * us, because pgd_clear() is a no-op on i386.
 548          */
 549         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 550 #ifdef CONFIG_X86_PAE
 551                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 552 #else
 553                 set_pgd(swapper_pg_dir+i, __pgd(0));
 554 #endif
 555         }
 556         flush_tlb_all();
 557 }
 558
 559 int nx_enabled;
 560
 561 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 562 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 563
 564 #ifdef CONFIG_X86_PAE
 565
 566 static int disable_nx __initdata;
 567
 568 /*
 569  * noexec = on|off
 570  *
 571  * Control non executable mappings.
 572  *
 573  * on      Enable
 574  * off     Disable
 575  */
 576 static int __init noexec_setup(char *str)
 577 {
 578         if (!str || !strcmp(str, "on")) {
 579                 if (cpu_has_nx) {
 580                         __supported_pte_mask |= _PAGE_NX;
 581                         disable_nx = 0;
 582                 }
 583         } else {
 584                 if (!strcmp(str, "off")) {
 585                         disable_nx = 1;
 586                         __supported_pte_mask &= ~_PAGE_NX;
 587                 } else {
 588                         return -EINVAL;
 589                 }
 590         }
 591
 592         return 0;
 593 }
 594 early_param("noexec", noexec_setup);
 595
 596 static void __init set_nx(void)
 597 {
 598         unsigned int v[4], l, h;
 599
 600         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 601                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 602
 603                 if ((v[3] & (1 << 20)) && !disable_nx) {
 604                         rdmsr(MSR_EFER, l, h);
 605                         l |= EFER_NX;
 606                         wrmsr(MSR_EFER, l, h);
 607                         nx_enabled = 1;
 608                         __supported_pte_mask |= _PAGE_NX;
 609                 }
 610         }
 611 }
 612 #endif
 613
 614 /* user-defined highmem size */
 615 static unsigned int highmem_pages = -1;
 616
 617 /*
 618  * highmem=size forces highmem to be exactly 'size' bytes.
 619  * This works even on boxes that have no highmem otherwise.
 620  * This also works to reduce highmem size on bigger boxes.
 621  */
 622 static int __init parse_highmem(char *arg)
 623 {
 624         if (!arg)
 625                 return -EINVAL;
 626
 627         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 628         return 0;
 629 }
 630 early_param("highmem", parse_highmem);
 631
 632 /*
 633  * Determine low and high memory ranges:
 634  */
 635 void __init find_low_pfn_range(void)
 636 {
 637         /* it could update max_pfn */
 638
 639         /* max_low_pfn is 0, we already have early_res support */
 640
 641         max_low_pfn = max_pfn;
 642         if (max_low_pfn > MAXMEM_PFN) {
 643                 if (highmem_pages == -1)
 644                         highmem_pages = max_pfn - MAXMEM_PFN;
 645                 if (highmem_pages + MAXMEM_PFN < max_pfn)
 646                         max_pfn = MAXMEM_PFN + highmem_pages;
 647                 if (highmem_pages + MAXMEM_PFN > max_pfn) {
 648                         printk(KERN_WARNING "only %luMB highmem pages "
 649                                 "available, ignoring highmem size of %uMB.\n",
 650                                 pages_to_mb(max_pfn - MAXMEM_PFN),
 651                                 pages_to_mb(highmem_pages));
 652                         highmem_pages = 0;
 653                 }
 654                 max_low_pfn = MAXMEM_PFN;
 655 #ifndef CONFIG_HIGHMEM
 656                 /* Maximum memory usable is what is directly addressable */
 657                 printk(KERN_WARNING "Warning only %ldMB will be used.\n",
 658                                         MAXMEM>>20);
 659                 if (max_pfn > MAX_NONPAE_PFN)
 660                         printk(KERN_WARNING
 661                                  "Use a HIGHMEM64G enabled kernel.\n");
 662                 else
 663                         printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 664                 max_pfn = MAXMEM_PFN;
 665 #else /* !CONFIG_HIGHMEM */
 666 #ifndef CONFIG_HIGHMEM64G
 667                 if (max_pfn > MAX_NONPAE_PFN) {
 668                         max_pfn = MAX_NONPAE_PFN;
 669                         printk(KERN_WARNING "Warning only 4GB will be used."
 670                                 "Use a HIGHMEM64G enabled kernel.\n");
 671                 }
 672 #endif /* !CONFIG_HIGHMEM64G */
 673 #endif /* !CONFIG_HIGHMEM */
 674         } else {
 675                 if (highmem_pages == -1)
 676                         highmem_pages = 0;
 677 #ifdef CONFIG_HIGHMEM
 678                 if (highmem_pages >= max_pfn) {
 679                         printk(KERN_ERR "highmem size specified (%uMB) is "
 680                                 "bigger than pages available (%luMB)!.\n",
 681                                 pages_to_mb(highmem_pages),
 682                                 pages_to_mb(max_pfn));
 683                         highmem_pages = 0;
 684                 }
 685                 if (highmem_pages) {
 686                         if (max_low_pfn - highmem_pages <
 687                             64*1024*1024/PAGE_SIZE){
 688                                 printk(KERN_ERR "highmem size %uMB results in "
 689                                 "smaller than 64MB lowmem, ignoring it.\n"
 690                                         , pages_to_mb(highmem_pages));
 691                                 highmem_pages = 0;
 692                         }
 693                         max_low_pfn -= highmem_pages;
 694                 }
 695 #else
 696                 if (highmem_pages)
 697                         printk(KERN_ERR "ignoring highmem size on non-highmem"
 698                                         " kernel!\n");
 699 #endif
 700         }
 701 }
 702
 703 #ifndef CONFIG_NEED_MULTIPLE_NODES
 704 void __init initmem_init(unsigned long start_pfn,
 705                                   unsigned long end_pfn)
 706 {
 707 #ifdef CONFIG_HIGHMEM
 708         highstart_pfn = highend_pfn = max_pfn;
 709         if (max_pfn > max_low_pfn)
 710                 highstart_pfn = max_low_pfn;
 711         memory_present(0, 0, highend_pfn);
 712         e820_register_active_regions(0, 0, highend_pfn);
 713         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 714                 pages_to_mb(highend_pfn - highstart_pfn));
 715         num_physpages = highend_pfn;
 716         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 717 #else
 718         memory_present(0, 0, max_low_pfn);
 719         e820_register_active_regions(0, 0, max_low_pfn);
 720         num_physpages = max_low_pfn;
 721         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 722 #endif
 723 #ifdef CONFIG_FLATMEM
 724         max_mapnr = num_physpages;
 725 #endif
 726         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 727                         pages_to_mb(max_low_pfn));
 728
 729         setup_bootmem_allocator();
 730 }
 731 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 732
 733 static void __init zone_sizes_init(void)
 734 {
 735         unsigned long max_zone_pfns[MAX_NR_ZONES];
 736         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 737         max_zone_pfns[ZONE_DMA] =
 738                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 739         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 740 #ifdef CONFIG_HIGHMEM
 741         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 742 #endif
 743
 744         free_area_init_nodes(max_zone_pfns);
 745 }
 746
 747 void __init setup_bootmem_allocator(void)
 748 {
 749         int i;
 750         unsigned long bootmap_size, bootmap;
 751         /*
 752          * Initialize the boot-time allocator (with low memory only):
 753          */
 754         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 755         bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
 756                                  max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 757                                  PAGE_SIZE);
 758         if (bootmap == -1L)
 759                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 760         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 761
 762         /* don't touch min_low_pfn */
 763         bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
 764                                          min_low_pfn, max_low_pfn);
 765         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 766                  max_pfn_mapped<<PAGE_SHIFT);
 767         printk(KERN_INFO "  low ram: %08lx - %08lx\n",
 768                  min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
 769         printk(KERN_INFO "  bootmap %08lx - %08lx\n",
 770                  bootmap, bootmap + bootmap_size);
 771         for_each_online_node(i)
 772                 free_bootmem_with_active_regions(i, max_low_pfn);
 773         early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
 774
 775         after_init_bootmem = 1;
 776 }
 777
 778 static void __init find_early_table_space(unsigned long end, int use_pse)
 779 {
 780         unsigned long puds, pmds, ptes, tables, start;
 781
 782         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
 783         tables = PAGE_ALIGN(puds * sizeof(pud_t));
 784
 785         pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
 786         tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
 787
 788         if (use_pse) {
 789                 unsigned long extra;
 790
 791                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
 792                 extra += PMD_SIZE;
 793                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 794         } else
 795                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
 796
 797         tables += PAGE_ALIGN(ptes * sizeof(pte_t));
 798
 799         /* for fixmap */
 800         tables += PAGE_SIZE * 2;
 801
 802         /*
 803          * RED-PEN putting page tables only on node 0 could
 804          * cause a hotspot and fill up ZONE_DMA. The page tables
 805          * need roughly 0.5KB per GB.
 806          */
 807         start = 0x7000;
 808         table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
 809                                         tables, PAGE_SIZE);
 810         if (table_start == -1UL)
 811                 panic("Cannot find space for the kernel page tables");
 812
 813         table_start >>= PAGE_SHIFT;
 814         table_end = table_start;
 815         table_top = table_start + (tables>>PAGE_SHIFT);
 816
 817         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 818                 end, table_start << PAGE_SHIFT,
 819                 (table_start << PAGE_SHIFT) + tables);
 820 }
 821
 822 unsigned long __init_refok init_memory_mapping(unsigned long start,
 823                                                 unsigned long end)
 824 {
 825         pgd_t *pgd_base = swapper_pg_dir;
 826         unsigned long start_pfn, end_pfn;
 827         unsigned long big_page_start;
 828 #ifdef CONFIG_DEBUG_PAGEALLOC
 829         /*
 830          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 831          * This will simplify cpa(), which otherwise needs to support splitting
 832          * large pages into small in interrupt context, etc.
 833          */
 834         int use_pse = 0;
 835 #else
 836         int use_pse = cpu_has_pse;
 837 #endif
 838
 839         /*
 840          * Find space for the kernel direct mapping tables.
 841          */
 842         if (!after_init_bootmem)
 843                 find_early_table_space(end, use_pse);
 844
 845 #ifdef CONFIG_X86_PAE
 846         set_nx();
 847         if (nx_enabled)
 848                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 849 #endif
 850
 851         /* Enable PSE if available */
 852         if (cpu_has_pse)
 853                 set_in_cr4(X86_CR4_PSE);
 854
 855         /* Enable PGE if available */
 856         if (cpu_has_pge) {
 857                 set_in_cr4(X86_CR4_PGE);
 858                 __supported_pte_mask |= _PAGE_GLOBAL;
 859         }
 860
 861         /*
 862          * Don't use a large page for the first 2/4MB of memory
 863          * because there are often fixed size MTRRs in there
 864          * and overlapping MTRRs into large pages can cause
 865          * slowdowns.
 866          */
 867         big_page_start = PMD_SIZE;
 868
 869         if (start < big_page_start) {
 870                 start_pfn = start >> PAGE_SHIFT;
 871                 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
 872         } else {
 873                 /* head is not big page alignment ? */
 874                 start_pfn = start >> PAGE_SHIFT;
 875                 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 876                                  << (PMD_SHIFT - PAGE_SHIFT);
 877         }
 878         if (start_pfn < end_pfn)
 879                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
 880
 881         /* big page range */
 882         start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 883                          << (PMD_SHIFT - PAGE_SHIFT);
 884         if (start_pfn < (big_page_start >> PAGE_SHIFT))
 885                 start_pfn =  big_page_start >> PAGE_SHIFT;
 886         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 887         if (start_pfn < end_pfn)
 888                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
 889                                              use_pse);
 890
 891         /* tail is not big page alignment ? */
 892         start_pfn = end_pfn;
 893         if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
 894                 end_pfn = end >> PAGE_SHIFT;
 895                 if (start_pfn < end_pfn)
 896                         kernel_physical_mapping_init(pgd_base, start_pfn,
 897                                                          end_pfn, 0);
 898         }
 899
 900         early_ioremap_page_table_range_init(pgd_base);
 901
 902         load_cr3(swapper_pg_dir);
 903
 904         __flush_tlb_all();
 905
 906         if (!after_init_bootmem)
 907                 reserve_early(table_start << PAGE_SHIFT,
 908                                  table_end << PAGE_SHIFT, "PGTABLE");
 909
 910         if (!after_init_bootmem)
 911                 early_memtest(start, end);
 912
 913         return end >> PAGE_SHIFT;
 914 }
 915
 916
 917 /*
 918  * paging_init() sets up the page tables - note that the first 8MB are
 919  * already mapped by head.S.
 920  *
 921  * This routines also unmaps the page at virtual kernel address 0, so
 922  * that we can trap those pesky NULL-reference errors in the kernel.
 923  */
 924 void __init paging_init(void)
 925 {
 926         pagetable_init();
 927
 928         __flush_tlb_all();
 929
 930         kmap_init();
 931
 932         /*
 933          * NOTE: at this point the bootmem allocator is fully available.
 934          */
 935         sparse_init();
 936         zone_sizes_init();
 937 }
 938
 939 /*
 940  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 941  * and also on some strange 486's. All 586+'s are OK. This used to involve
 942  * black magic jumps to work around some nasty CPU bugs, but fortunately the
 943  * switch to using exceptions got rid of all that.
 944  */
 945 static void __init test_wp_bit(void)
 946 {
 947         printk(KERN_INFO
 948   "Checking if this processor honours the WP bit even in supervisor mode...");
 949
 950         /* Any page-aligned address will do, the test is non-destructive */
 951         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 952         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 953         clear_fixmap(FIX_WP_TEST);
 954
 955         if (!boot_cpu_data.wp_works_ok) {
 956                 printk(KERN_CONT "No.\n");
 957 #ifdef CONFIG_X86_WP_WORKS_OK
 958                 panic(
 959   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 960 #endif
 961         } else {
 962                 printk(KERN_CONT "Ok.\n");
 963         }
 964 }
 965
 966 static struct kcore_list kcore_mem, kcore_vmalloc;
 967
 968 void __init mem_init(void)
 969 {
 970         int codesize, reservedpages, datasize, initsize;
 971         int tmp;
 972
 973         start_periodic_check_for_corruption();
 974
 975 #ifdef CONFIG_FLATMEM
 976         BUG_ON(!mem_map);
 977 #endif
 978         /* this will put all low memory onto the freelists */
 979         totalram_pages += free_all_bootmem();
 980
 981         reservedpages = 0;
 982         for (tmp = 0; tmp < max_low_pfn; tmp++)
 983                 /*
 984                  * Only count reserved RAM pages:
 985                  */
 986                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 987                         reservedpages++;
 988
 989         set_highmem_pages_init();
 990
 991         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 992         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 993         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 994
 995         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 996         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 997                    VMALLOC_END-VMALLOC_START);
 998
 999         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
1000                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
1001                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
1002                 num_physpages << (PAGE_SHIFT-10),
1003                 codesize >> 10,
1004                 reservedpages << (PAGE_SHIFT-10),
1005                 datasize >> 10,
1006                 initsize >> 10,
1007                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
1008                );
1009
1010         printk(KERN_INFO "virtual kernel memory layout:\n"
1011                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1012 #ifdef CONFIG_HIGHMEM
1013                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1014 #endif
1015                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1016                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1017                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1018                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1019                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
1020                 FIXADDR_START, FIXADDR_TOP,
1021                 (FIXADDR_TOP - FIXADDR_START) >> 10,
1022
1023 #ifdef CONFIG_HIGHMEM
1024                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
1025                 (LAST_PKMAP*PAGE_SIZE) >> 10,
1026 #endif
1027
1028                 VMALLOC_START, VMALLOC_END,
1029                 (VMALLOC_END - VMALLOC_START) >> 20,
1030
1031                 (unsigned long)__va(0), (unsigned long)high_memory,
1032                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
1033
1034                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
1035                 ((unsigned long)&__init_end -
1036                  (unsigned long)&__init_begin) >> 10,
1037
1038                 (unsigned long)&_etext, (unsigned long)&_edata,
1039                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
1040
1041                 (unsigned long)&_text, (unsigned long)&_etext,
1042                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
1043
1044 #ifdef CONFIG_HIGHMEM
1045         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
1046         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
1047 #endif
1048         BUG_ON(VMALLOC_START                            > VMALLOC_END);
1049         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
1050
1051         if (boot_cpu_data.wp_works_ok < 0)
1052                 test_wp_bit();
1053
1054         save_pg_dir();
1055         zap_low_mappings();
1056 }
1057
1058 #ifdef CONFIG_MEMORY_HOTPLUG
1059 int arch_add_memory(int nid, u64 start, u64 size)
1060 {
1061         struct pglist_data *pgdata = NODE_DATA(nid);
1062         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1063         unsigned long start_pfn = start >> PAGE_SHIFT;
1064         unsigned long nr_pages = size >> PAGE_SHIFT;
1065
1066         return __add_pages(zone, start_pfn, nr_pages);
1067 }
1068 #endif
1069
1070 /*
1071  * This function cannot be __init, since exceptions don't work in that
1072  * section.  Put this after the callers, so that it cannot be inlined.
1073  */
1074 static noinline int do_test_wp_bit(void)
1075 {
1076         char tmp_reg;
1077         int flag;
1078
1079         __asm__ __volatile__(
1080                 "       movb %0, %1     \n"
1081                 "1:     movb %1, %0     \n"
1082                 "       xorl %2, %2     \n"
1083                 "2:                     \n"
1084                 _ASM_EXTABLE(1b,2b)
1085                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1086                  "=q" (tmp_reg),
1087                  "=r" (flag)
1088                 :"2" (1)
1089                 :"memory");
1090
1091         return flag;
1092 }
1093
1094 #ifdef CONFIG_DEBUG_RODATA
1095 const int rodata_test_data = 0xC3;
1096 EXPORT_SYMBOL_GPL(rodata_test_data);
1097
1098 void mark_rodata_ro(void)
1099 {
1100         unsigned long start = PFN_ALIGN(_text);
1101         unsigned long size = PFN_ALIGN(_etext) - start;
1102
1103 #ifndef CONFIG_DYNAMIC_FTRACE
1104         /* Dynamic tracing modifies the kernel text section */
1105         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1106         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1107                 size >> 10);
1108
1109 #ifdef CONFIG_CPA_DEBUG
1110         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1111                 start, start+size);
1112         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1113
1114         printk(KERN_INFO "Testing CPA: write protecting again\n");
1115         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1116 #endif
1117 #endif /* CONFIG_DYNAMIC_FTRACE */
1118
1119         start += size;
1120         size = (unsigned long)__end_rodata - start;
1121         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1122         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1123                 size >> 10);
1124         rodata_test();
1125
1126 #ifdef CONFIG_CPA_DEBUG
1127         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1128         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1129
1130         printk(KERN_INFO "Testing CPA: write protecting again\n");
1131         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1132 #endif
1133 }
1134 #endif
1135
1136 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1137 {
1138 #ifdef CONFIG_DEBUG_PAGEALLOC
1139         /*
1140          * If debugging page accesses then do not free this memory but
1141          * mark them not present - any buggy init-section access will
1142          * create a kernel page fault:
1143          */
1144         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1145                 begin, PAGE_ALIGN(end));
1146         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1147 #else
1148         unsigned long addr;
1149
1150         /*
1151          * We just marked the kernel text read only above, now that
1152          * we are going to free part of that, we need to make that
1153          * writeable first.
1154          */
1155         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1156
1157         for (addr = begin; addr < end; addr += PAGE_SIZE) {
1158                 ClearPageReserved(virt_to_page(addr));
1159                 init_page_count(virt_to_page(addr));
1160                 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1161                 free_page(addr);
1162                 totalram_pages++;
1163         }
1164         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1165 #endif
1166 }
1167
1168 void free_initmem(void)
1169 {
1170         free_init_pages("unused kernel memory",
1171                         (unsigned long)(&__init_begin),
1172                         (unsigned long)(&__init_end));
1173 }
1174
1175 #ifdef CONFIG_BLK_DEV_INITRD
1176 void free_initrd_mem(unsigned long start, unsigned long end)
1177 {
1178         free_init_pages("initrd memory", start, end);
1179 }
1180 #endif
1181
1182 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1183                                    int flags)
1184 {
1185         return reserve_bootmem(phys, len, flags);
1186 }