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