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