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/pci.h>
  25 #include <linux/pfn.h>
  26 #include <linux/poison.h>
  27 #include <linux/bootmem.h>
  28 #include <linux/slab.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/memory_hotplug.h>
  31 #include <linux/initrd.h>
  32 #include <linux/cpumask.h>
  33
  34 #include <asm/asm.h>
  35 #include <asm/bios_ebda.h>
  36 #include <asm/processor.h>
  37 #include <asm/system.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/dma.h>
  41 #include <asm/fixmap.h>
  42 #include <asm/e820.h>
  43 #include <asm/apic.h>
  44 #include <asm/bugs.h>
  45 #include <asm/tlb.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/pgalloc.h>
  48 #include <asm/sections.h>
  49 #include <asm/paravirt.h>
  50 #include <asm/setup.h>
  51 #include <asm/cacheflush.h>
  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(void)
  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         return adr;
  79 }
  80
  81 /*
  82  * Creates a middle page table and puts a pointer to it in the
  83  * given global directory entry. This only returns the gd entry
  84  * in non-PAE compilation mode, since the middle layer is folded.
  85  */
  86 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  87 {
  88         pud_t *pud;
  89         pmd_t *pmd_table;
  90
  91 #ifdef CONFIG_X86_PAE
  92         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  93                 if (after_init_bootmem)
  94                         pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  95                 else
  96                         pmd_table = (pmd_t *)alloc_low_page();
  97                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
  98                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  99                 pud = pud_offset(pgd, 0);
 100                 BUG_ON(pmd_table != pmd_offset(pud, 0));
 101
 102                 return pmd_table;
 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                         page_table = (pte_t *)alloc_low_page();
 129
 130                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 131                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 132                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 133         }
 134
 135         return pte_offset_kernel(pmd, 0);
 136 }
 137
 138 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
 139                                            unsigned long vaddr, pte_t *lastpte)
 140 {
 141 #ifdef CONFIG_HIGHMEM
 142         /*
 143          * Something (early fixmap) may already have put a pte
 144          * page here, which causes the page table allocation
 145          * to become nonlinear. Attempt to fix it, and if it
 146          * is still nonlinear then we have to bug.
 147          */
 148         int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
 149         int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
 150
 151         if (pmd_idx_kmap_begin != pmd_idx_kmap_end
 152             && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
 153             && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
 154             && ((__pa(pte) >> PAGE_SHIFT) < table_start
 155                 || (__pa(pte) >> PAGE_SHIFT) >= table_end)) {
 156                 pte_t *newpte;
 157                 int i;
 158
 159                 BUG_ON(after_init_bootmem);
 160                 newpte = alloc_low_page();
 161                 for (i = 0; i < PTRS_PER_PTE; i++)
 162                         set_pte(newpte + i, pte[i]);
 163
 164                 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
 165                 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
 166                 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
 167                 __flush_tlb_all();
 168
 169                 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
 170                 pte = newpte;
 171         }
 172         BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
 173                && vaddr > fix_to_virt(FIX_KMAP_END)
 174                && lastpte && lastpte + PTRS_PER_PTE != pte);
 175 #endif
 176         return pte;
 177 }
 178
 179 /*
 180  * This function initializes a certain range of kernel virtual memory
 181  * with new bootmem page tables, everywhere page tables are missing in
 182  * the given range.
 183  *
 184  * NOTE: The pagetables are allocated contiguous on the physical space
 185  * so we can cache the place of the first one and move around without
 186  * checking the pgd every time.
 187  */
 188 static void __init
 189 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 190 {
 191         int pgd_idx, pmd_idx;
 192         unsigned long vaddr;
 193         pgd_t *pgd;
 194         pmd_t *pmd;
 195         pte_t *pte = NULL;
 196
 197         vaddr = start;
 198         pgd_idx = pgd_index(vaddr);
 199         pmd_idx = pmd_index(vaddr);
 200         pgd = pgd_base + pgd_idx;
 201
 202         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 203                 pmd = one_md_table_init(pgd);
 204                 pmd = pmd + pmd_index(vaddr);
 205                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 206                                                         pmd++, pmd_idx++) {
 207                         pte = page_table_kmap_check(one_page_table_init(pmd),
 208                                                     pmd, vaddr, pte);
 209
 210                         vaddr += PMD_SIZE;
 211                 }
 212                 pmd_idx = 0;
 213         }
 214 }
 215
 216 static inline int is_kernel_text(unsigned long addr)
 217 {
 218         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 219                 return 1;
 220         return 0;
 221 }
 222
 223 /*
 224  * This maps the physical memory to kernel virtual address space, a total
 225  * of max_low_pfn pages, by creating page tables starting from address
 226  * PAGE_OFFSET:
 227  */
 228 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
 229                                                 unsigned long start_pfn,
 230                                                 unsigned long end_pfn,
 231                                                 int use_pse)
 232 {
 233         int pgd_idx, pmd_idx, pte_ofs;
 234         unsigned long pfn;
 235         pgd_t *pgd;
 236         pmd_t *pmd;
 237         pte_t *pte;
 238         unsigned pages_2m, pages_4k;
 239         int mapping_iter;
 240
 241         /*
 242          * First iteration will setup identity mapping using large/small pages
 243          * based on use_pse, with other attributes same as set by
 244          * the early code in head_32.S
 245          *
 246          * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
 247          * as desired for the kernel identity mapping.
 248          *
 249          * This two pass mechanism conforms to the TLB app note which says:
 250          *
 251          *     "Software should not write to a paging-structure entry in a way
 252          *      that would change, for any linear address, both the page size
 253          *      and either the page frame or attributes."
 254          */
 255         mapping_iter = 1;
 256
 257         if (!cpu_has_pse)
 258                 use_pse = 0;
 259
 260 repeat:
 261         pages_2m = pages_4k = 0;
 262         pfn = start_pfn;
 263         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 264         pgd = pgd_base + pgd_idx;
 265         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 266                 pmd = one_md_table_init(pgd);
 267
 268                 if (pfn >= end_pfn)
 269                         continue;
 270 #ifdef CONFIG_X86_PAE
 271                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 272                 pmd += pmd_idx;
 273 #else
 274                 pmd_idx = 0;
 275 #endif
 276                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 277                      pmd++, pmd_idx++) {
 278                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 279
 280                         /*
 281                          * Map with big pages if possible, otherwise
 282                          * create normal page tables:
 283                          */
 284                         if (use_pse) {
 285                                 unsigned int addr2;
 286                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 287                                 /*
 288                                  * first pass will use the same initial
 289                                  * identity mapping attribute + _PAGE_PSE.
 290                                  */
 291                                 pgprot_t init_prot =
 292                                         __pgprot(PTE_IDENT_ATTR |
 293                                                  _PAGE_PSE);
 294
 295                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 296                                         PAGE_OFFSET + PAGE_SIZE-1;
 297
 298                                 if (is_kernel_text(addr) ||
 299                                     is_kernel_text(addr2))
 300                                         prot = PAGE_KERNEL_LARGE_EXEC;
 301
 302                                 pages_2m++;
 303                                 if (mapping_iter == 1)
 304                                         set_pmd(pmd, pfn_pmd(pfn, init_prot));
 305                                 else
 306                                         set_pmd(pmd, pfn_pmd(pfn, prot));
 307
 308                                 pfn += PTRS_PER_PTE;
 309                                 continue;
 310                         }
 311                         pte = one_page_table_init(pmd);
 312
 313                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 314                         pte += pte_ofs;
 315                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 316                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 317                                 pgprot_t prot = PAGE_KERNEL;
 318                                 /*
 319                                  * first pass will use the same initial
 320                                  * identity mapping attribute.
 321                                  */
 322                                 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 323
 324                                 if (is_kernel_text(addr))
 325                                         prot = PAGE_KERNEL_EXEC;
 326
 327                                 pages_4k++;
 328                                 if (mapping_iter == 1)
 329                                         set_pte(pte, pfn_pte(pfn, init_prot));
 330                                 else
 331                                         set_pte(pte, pfn_pte(pfn, prot));
 332                         }
 333                 }
 334         }
 335         if (mapping_iter == 1) {
 336                 /*
 337                  * update direct mapping page count only in the first
 338                  * iteration.
 339                  */
 340                 update_page_count(PG_LEVEL_2M, pages_2m);
 341                 update_page_count(PG_LEVEL_4K, pages_4k);
 342
 343                 /*
 344                  * local global flush tlb, which will flush the previous
 345                  * mappings present in both small and large page TLB's.
 346                  */
 347                 __flush_tlb_all();
 348
 349                 /*
 350                  * Second iteration will set the actual desired PTE attributes.
 351                  */
 352                 mapping_iter = 2;
 353                 goto repeat;
 354         }
 355 }
 356
 357 pte_t *kmap_pte;
 358 pgprot_t kmap_prot;
 359
 360 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 361 {
 362         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 363                         vaddr), vaddr), vaddr);
 364 }
 365
 366 static void __init kmap_init(void)
 367 {
 368         unsigned long kmap_vstart;
 369
 370         /*
 371          * Cache the first kmap pte:
 372          */
 373         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 374         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 375
 376         kmap_prot = PAGE_KERNEL;
 377 }
 378
 379 #ifdef CONFIG_HIGHMEM
 380 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 381 {
 382         unsigned long vaddr;
 383         pgd_t *pgd;
 384         pud_t *pud;
 385         pmd_t *pmd;
 386         pte_t *pte;
 387
 388         vaddr = PKMAP_BASE;
 389         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 390
 391         pgd = swapper_pg_dir + pgd_index(vaddr);
 392         pud = pud_offset(pgd, vaddr);
 393         pmd = pmd_offset(pud, vaddr);
 394         pte = pte_offset_kernel(pmd, vaddr);
 395         pkmap_page_table = pte;
 396 }
 397
 398 static void __init add_one_highpage_init(struct page *page, int pfn)
 399 {
 400         ClearPageReserved(page);
 401         init_page_count(page);
 402         __free_page(page);
 403         totalhigh_pages++;
 404 }
 405
 406 struct add_highpages_data {
 407         unsigned long start_pfn;
 408         unsigned long end_pfn;
 409 };
 410
 411 static int __init add_highpages_work_fn(unsigned long start_pfn,
 412                                          unsigned long end_pfn, void *datax)
 413 {
 414         int node_pfn;
 415         struct page *page;
 416         unsigned long final_start_pfn, final_end_pfn;
 417         struct add_highpages_data *data;
 418
 419         data = (struct add_highpages_data *)datax;
 420
 421         final_start_pfn = max(start_pfn, data->start_pfn);
 422         final_end_pfn = min(end_pfn, data->end_pfn);
 423         if (final_start_pfn >= final_end_pfn)
 424                 return 0;
 425
 426         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 427              node_pfn++) {
 428                 if (!pfn_valid(node_pfn))
 429                         continue;
 430                 page = pfn_to_page(node_pfn);
 431                 add_one_highpage_init(page, node_pfn);
 432         }
 433
 434         return 0;
 435
 436 }
 437
 438 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 439                                               unsigned long end_pfn)
 440 {
 441         struct add_highpages_data data;
 442
 443         data.start_pfn = start_pfn;
 444         data.end_pfn = end_pfn;
 445
 446         work_with_active_regions(nid, add_highpages_work_fn, &data);
 447 }
 448
 449 #else
 450 static inline void permanent_kmaps_init(pgd_t *pgd_base)
 451 {
 452 }
 453 #endif /* CONFIG_HIGHMEM */
 454
 455 void __init native_pagetable_setup_start(pgd_t *base)
 456 {
 457         unsigned long pfn, va;
 458         pgd_t *pgd;
 459         pud_t *pud;
 460         pmd_t *pmd;
 461         pte_t *pte;
 462
 463         /*
 464          * Remove any mappings which extend past the end of physical
 465          * memory from the boot time page table:
 466          */
 467         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 468                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 469                 pgd = base + pgd_index(va);
 470                 if (!pgd_present(*pgd))
 471                         break;
 472
 473                 pud = pud_offset(pgd, va);
 474                 pmd = pmd_offset(pud, va);
 475                 if (!pmd_present(*pmd))
 476                         break;
 477
 478                 pte = pte_offset_kernel(pmd, va);
 479                 if (!pte_present(*pte))
 480                         break;
 481
 482                 pte_clear(NULL, va, pte);
 483         }
 484         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 485 }
 486
 487 void __init native_pagetable_setup_done(pgd_t *base)
 488 {
 489 }
 490
 491 /*
 492  * Build a proper pagetable for the kernel mappings.  Up until this
 493  * point, we've been running on some set of pagetables constructed by
 494  * the boot process.
 495  *
 496  * If we're booting on native hardware, this will be a pagetable
 497  * constructed in arch/x86/kernel/head_32.S.  The root of the
 498  * pagetable will be swapper_pg_dir.
 499  *
 500  * If we're booting paravirtualized under a hypervisor, then there are
 501  * more options: we may already be running PAE, and the pagetable may
 502  * or may not be based in swapper_pg_dir.  In any case,
 503  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 504  * appropriately for the rest of the initialization to work.
 505  *
 506  * In general, pagetable_init() assumes that the pagetable may already
 507  * be partially populated, and so it avoids stomping on any existing
 508  * mappings.
 509  */
 510 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
 511 {
 512         unsigned long vaddr, end;
 513
 514         /*
 515          * Fixed mappings, only the page table structure has to be
 516          * created - mappings will be set by set_fixmap():
 517          */
 518         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 519         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 520         page_table_range_init(vaddr, end, pgd_base);
 521         early_ioremap_reset();
 522 }
 523
 524 static void __init pagetable_init(void)
 525 {
 526         pgd_t *pgd_base = swapper_pg_dir;
 527
 528         permanent_kmaps_init(pgd_base);
 529 }
 530
 531 #ifdef CONFIG_ACPI_SLEEP
 532 /*
 533  * ACPI suspend needs this for resume, because things like the intel-agp
 534  * driver might have split up a kernel 4MB mapping.
 535  */
 536 char swsusp_pg_dir[PAGE_SIZE]
 537         __attribute__ ((aligned(PAGE_SIZE)));
 538
 539 static inline void save_pg_dir(void)
 540 {
 541         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 542 }
 543 #else /* !CONFIG_ACPI_SLEEP */
 544 static inline void save_pg_dir(void)
 545 {
 546 }
 547 #endif /* !CONFIG_ACPI_SLEEP */
 548
 549 void zap_low_mappings(void)
 550 {
 551         int i;
 552
 553         /*
 554          * Zap initial low-memory mappings.
 555          *
 556          * Note that "pgd_clear()" doesn't do it for
 557          * us, because pgd_clear() is a no-op on i386.
 558          */
 559         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 560 #ifdef CONFIG_X86_PAE
 561                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 562 #else
 563                 set_pgd(swapper_pg_dir+i, __pgd(0));
 564 #endif
 565         }
 566         flush_tlb_all();
 567 }
 568
 569 int nx_enabled;
 570
 571 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 572 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 573
 574 #ifdef CONFIG_X86_PAE
 575
 576 static int disable_nx __initdata;
 577
 578 /*
 579  * noexec = on|off
 580  *
 581  * Control non executable mappings.
 582  *
 583  * on      Enable
 584  * off     Disable
 585  */
 586 static int __init noexec_setup(char *str)
 587 {
 588         if (!str || !strcmp(str, "on")) {
 589                 if (cpu_has_nx) {
 590                         __supported_pte_mask |= _PAGE_NX;
 591                         disable_nx = 0;
 592                 }
 593         } else {
 594                 if (!strcmp(str, "off")) {
 595                         disable_nx = 1;
 596                         __supported_pte_mask &= ~_PAGE_NX;
 597                 } else {
 598                         return -EINVAL;
 599                 }
 600         }
 601
 602         return 0;
 603 }
 604 early_param("noexec", noexec_setup);
 605
 606 static void __init set_nx(void)
 607 {
 608         unsigned int v[4], l, h;
 609
 610         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 611                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 612
 613                 if ((v[3] & (1 << 20)) && !disable_nx) {
 614                         rdmsr(MSR_EFER, l, h);
 615                         l |= EFER_NX;
 616                         wrmsr(MSR_EFER, l, h);
 617                         nx_enabled = 1;
 618                         __supported_pte_mask |= _PAGE_NX;
 619                 }
 620         }
 621 }
 622 #endif
 623
 624 /* user-defined highmem size */
 625 static unsigned int highmem_pages = -1;
 626
 627 /*
 628  * highmem=size forces highmem to be exactly 'size' bytes.
 629  * This works even on boxes that have no highmem otherwise.
 630  * This also works to reduce highmem size on bigger boxes.
 631  */
 632 static int __init parse_highmem(char *arg)
 633 {
 634         if (!arg)
 635                 return -EINVAL;
 636
 637         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 638         return 0;
 639 }
 640 early_param("highmem", parse_highmem);
 641
 642 #define MSG_HIGHMEM_TOO_BIG \
 643         "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
 644
 645 #define MSG_LOWMEM_TOO_SMALL \
 646         "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
 647 /*
 648  * All of RAM fits into lowmem - but if user wants highmem
 649  * artificially via the highmem=x boot parameter then create
 650  * it:
 651  */
 652 void __init lowmem_pfn_init(void)
 653 {
 654         /* max_low_pfn is 0, we already have early_res support */
 655         max_low_pfn = max_pfn;
 656
 657         if (highmem_pages == -1)
 658                 highmem_pages = 0;
 659 #ifdef CONFIG_HIGHMEM
 660         if (highmem_pages >= max_pfn) {
 661                 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
 662                         pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
 663                 highmem_pages = 0;
 664         }
 665         if (highmem_pages) {
 666                 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
 667                         printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
 668                                 pages_to_mb(highmem_pages));
 669                         highmem_pages = 0;
 670                 }
 671                 max_low_pfn -= highmem_pages;
 672         }
 673 #else
 674         if (highmem_pages)
 675                 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
 676 #endif
 677 }
 678
 679 #define MSG_HIGHMEM_TOO_SMALL \
 680         "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
 681
 682 #define MSG_HIGHMEM_TRIMMED \
 683         "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
 684 /*
 685  * We have more RAM than fits into lowmem - we try to put it into
 686  * highmem, also taking the highmem=x boot parameter into account:
 687  */
 688 void __init highmem_pfn_init(void)
 689 {
 690         max_low_pfn = MAXMEM_PFN;
 691
 692         if (highmem_pages == -1)
 693                 highmem_pages = max_pfn - MAXMEM_PFN;
 694
 695         if (highmem_pages + MAXMEM_PFN < max_pfn)
 696                 max_pfn = MAXMEM_PFN + highmem_pages;
 697
 698         if (highmem_pages + MAXMEM_PFN > max_pfn) {
 699                 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
 700                         pages_to_mb(max_pfn - MAXMEM_PFN),
 701                         pages_to_mb(highmem_pages));
 702                 highmem_pages = 0;
 703         }
 704 #ifndef CONFIG_HIGHMEM
 705         /* Maximum memory usable is what is directly addressable */
 706         printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
 707         if (max_pfn > MAX_NONPAE_PFN)
 708                 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
 709         else
 710                 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 711         max_pfn = MAXMEM_PFN;
 712 #else /* !CONFIG_HIGHMEM */
 713 #ifndef CONFIG_HIGHMEM64G
 714         if (max_pfn > MAX_NONPAE_PFN) {
 715                 max_pfn = MAX_NONPAE_PFN;
 716                 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
 717         }
 718 #endif /* !CONFIG_HIGHMEM64G */
 719 #endif /* !CONFIG_HIGHMEM */
 720 }
 721
 722 /*
 723  * Determine low and high memory ranges:
 724  */
 725 void __init find_low_pfn_range(void)
 726 {
 727         /* it could update max_pfn */
 728
 729         if (max_pfn <= MAXMEM_PFN)
 730                 lowmem_pfn_init();
 731         else
 732                 highmem_pfn_init();
 733 }
 734
 735 #ifndef CONFIG_NEED_MULTIPLE_NODES
 736 void __init initmem_init(unsigned long start_pfn,
 737                                   unsigned long end_pfn)
 738 {
 739 #ifdef CONFIG_HIGHMEM
 740         highstart_pfn = highend_pfn = max_pfn;
 741         if (max_pfn > max_low_pfn)
 742                 highstart_pfn = max_low_pfn;
 743         memory_present(0, 0, highend_pfn);
 744         e820_register_active_regions(0, 0, highend_pfn);
 745         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 746                 pages_to_mb(highend_pfn - highstart_pfn));
 747         num_physpages = highend_pfn;
 748         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 749 #else
 750         memory_present(0, 0, max_low_pfn);
 751         e820_register_active_regions(0, 0, max_low_pfn);
 752         num_physpages = max_low_pfn;
 753         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 754 #endif
 755 #ifdef CONFIG_FLATMEM
 756         max_mapnr = num_physpages;
 757 #endif
 758         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 759                         pages_to_mb(max_low_pfn));
 760
 761         setup_bootmem_allocator();
 762 }
 763 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 764
 765 static void __init zone_sizes_init(void)
 766 {
 767         unsigned long max_zone_pfns[MAX_NR_ZONES];
 768         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 769         max_zone_pfns[ZONE_DMA] =
 770                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 771         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 772 #ifdef CONFIG_HIGHMEM
 773         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 774 #endif
 775
 776         free_area_init_nodes(max_zone_pfns);
 777 }
 778
 779 static unsigned long __init setup_node_bootmem(int nodeid,
 780                                  unsigned long start_pfn,
 781                                  unsigned long end_pfn,
 782                                  unsigned long bootmap)
 783 {
 784         unsigned long bootmap_size;
 785
 786         if (start_pfn > max_low_pfn)
 787                 return bootmap;
 788         if (end_pfn > max_low_pfn)
 789                 end_pfn = max_low_pfn;
 790
 791         /* don't touch min_low_pfn */
 792         bootmap_size = init_bootmem_node(NODE_DATA(nodeid),
 793                                          bootmap >> PAGE_SHIFT,
 794                                          start_pfn, end_pfn);
 795         printk(KERN_INFO "  node %d low ram: %08lx - %08lx\n",
 796                 nodeid, start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
 797         printk(KERN_INFO "  node %d bootmap %08lx - %08lx\n",
 798                  nodeid, bootmap, bootmap + bootmap_size);
 799         free_bootmem_with_active_regions(nodeid, end_pfn);
 800         early_res_to_bootmem(start_pfn<<PAGE_SHIFT, end_pfn<<PAGE_SHIFT);
 801
 802         return bootmap + bootmap_size;
 803 }
 804
 805 void __init setup_bootmem_allocator(void)
 806 {
 807         int nodeid;
 808         unsigned long bootmap_size, bootmap;
 809         /*
 810          * Initialize the boot-time allocator (with low memory only):
 811          */
 812         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 813         bootmap = find_e820_area(0, max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 814                                  PAGE_SIZE);
 815         if (bootmap == -1L)
 816                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 817         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 818
 819         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 820                  max_pfn_mapped<<PAGE_SHIFT);
 821         printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);
 822
 823 #ifdef CONFIG_NEED_MULTIPLE_NODES
 824         for_each_online_node(nodeid)
 825                 bootmap = setup_node_bootmem(nodeid, node_start_pfn[nodeid],
 826                                         node_end_pfn[nodeid], bootmap);
 827 #else
 828         bootmap = setup_node_bootmem(0, 0, max_low_pfn, bootmap);
 829 #endif
 830
 831         after_init_bootmem = 1;
 832 }
 833
 834 static void __init find_early_table_space(unsigned long end, int use_pse)
 835 {
 836         unsigned long puds, pmds, ptes, tables, start;
 837
 838         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
 839         tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
 840
 841         pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
 842         tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
 843
 844         if (use_pse) {
 845                 unsigned long extra;
 846
 847                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
 848                 extra += PMD_SIZE;
 849                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 850         } else
 851                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
 852
 853         tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
 854
 855         /* for fixmap */
 856         tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
 857
 858         /*
 859          * RED-PEN putting page tables only on node 0 could
 860          * cause a hotspot and fill up ZONE_DMA. The page tables
 861          * need roughly 0.5KB per GB.
 862          */
 863         start = 0x7000;
 864         table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
 865                                         tables, PAGE_SIZE);
 866         if (table_start == -1UL)
 867                 panic("Cannot find space for the kernel page tables");
 868
 869         table_start >>= PAGE_SHIFT;
 870         table_end = table_start;
 871         table_top = table_start + (tables >> PAGE_SHIFT);
 872
 873         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 874                 end, table_start << PAGE_SHIFT, table_top << PAGE_SHIFT);
 875 }
 876
 877 struct map_range {
 878         unsigned long start;
 879         unsigned long end;
 880         unsigned page_size_mask;
 881 };
 882
 883 #define NR_RANGE_MR 3
 884
 885 static int save_mr(struct map_range *mr, int nr_range,
 886                    unsigned long start_pfn, unsigned long end_pfn,
 887                    unsigned long page_size_mask)
 888 {
 889         if (start_pfn < end_pfn) {
 890                 if (nr_range >= NR_RANGE_MR)
 891                         panic("run out of range for init_memory_mapping\n");
 892                 mr[nr_range].start = start_pfn<<PAGE_SHIFT;
 893                 mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
 894                 mr[nr_range].page_size_mask = page_size_mask;
 895                 nr_range++;
 896         }
 897
 898         return nr_range;
 899 }
 900
 901 /*
 902  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
 903  * This runs before bootmem is initialized and gets pages directly from
 904  * the physical memory. To access them they are temporarily mapped.
 905  */
 906 unsigned long __init_refok init_memory_mapping(unsigned long start,
 907                                                unsigned long end)
 908 {
 909         pgd_t *pgd_base = swapper_pg_dir;
 910         unsigned long page_size_mask = 0;
 911         unsigned long start_pfn, end_pfn;
 912         unsigned long pos;
 913
 914         struct map_range mr[NR_RANGE_MR];
 915         int nr_range, i;
 916         int use_pse;
 917
 918         printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
 919
 920 #ifdef CONFIG_DEBUG_PAGEALLOC
 921         /*
 922          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 923          * This will simplify cpa(), which otherwise needs to support splitting
 924          * large pages into small in interrupt context, etc.
 925          */
 926         use_pse = 0;
 927 #else
 928         use_pse = cpu_has_pse;
 929 #endif
 930
 931 #ifdef CONFIG_X86_PAE
 932         set_nx();
 933         if (nx_enabled)
 934                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 935 #endif
 936
 937         /* Enable PSE if available */
 938         if (cpu_has_pse)
 939                 set_in_cr4(X86_CR4_PSE);
 940
 941         /* Enable PGE if available */
 942         if (cpu_has_pge) {
 943                 set_in_cr4(X86_CR4_PGE);
 944                 __supported_pte_mask |= _PAGE_GLOBAL;
 945         }
 946
 947         if (use_pse)
 948                 page_size_mask |= 1 << PG_LEVEL_2M;
 949
 950         memset(mr, 0, sizeof(mr));
 951         nr_range = 0;
 952
 953         /*
 954          * Don't use a large page for the first 2/4MB of memory
 955          * because there are often fixed size MTRRs in there
 956          * and overlapping MTRRs into large pages can cause
 957          * slowdowns.
 958          */
 959         /* head if not big page alignment ? */
 960         start_pfn = start >> PAGE_SHIFT;
 961         pos = start_pfn << PAGE_SHIFT;
 962         if (pos == 0)
 963                 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
 964         else
 965                 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 966                                  << (PMD_SHIFT - PAGE_SHIFT);
 967         if (end_pfn > (end >> PAGE_SHIFT))
 968                 end_pfn = end >> PAGE_SHIFT;
 969         if (start_pfn < end_pfn) {
 970                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 971                 pos = end_pfn << PAGE_SHIFT;
 972         }
 973
 974         /* big page (2M) range */
 975         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 976                          << (PMD_SHIFT - PAGE_SHIFT);
 977         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 978         if (start_pfn < end_pfn) {
 979                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 980                                 page_size_mask & (1<<PG_LEVEL_2M));
 981                 pos = end_pfn << PAGE_SHIFT;
 982         }
 983
 984         /* tail is not big page (2M) alignment */
 985         start_pfn = pos>>PAGE_SHIFT;
 986         end_pfn = end>>PAGE_SHIFT;
 987         if (start_pfn < end_pfn)
 988                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 989
 990         /* try to merge same page size and continuous */
 991         for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
 992                 unsigned long old_start;
 993                 if (mr[i].end != mr[i+1].start ||
 994                     mr[i].page_size_mask != mr[i+1].page_size_mask)
 995                         continue;
 996                 /* move it */
 997                 old_start = mr[i].start;
 998                 memmove(&mr[i], &mr[i+1],
 999                         (nr_range - 1 - i) * sizeof(struct map_range));
1000                 mr[i--].start = old_start;
1001                 nr_range--;
1002         }
1003
1004         for (i = 0; i < nr_range; i++)
1005                 printk(KERN_DEBUG " %010lx - %010lx page %s\n",
1006                                 mr[i].start, mr[i].end,
1007                         (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
1008                          (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
1009
1010         /*
1011          * Find space for the kernel direct mapping tables.
1012          *
1013          * Later we should allocate these tables in the local node of the
1014          * memory mapped. Unfortunately this is done currently before the
1015          * nodes are discovered.
1016          */
1017         if (!after_init_bootmem)
1018                 find_early_table_space(end, use_pse);
1019
1020         for (i = 0; i < nr_range; i++)
1021                 kernel_physical_mapping_init(pgd_base,
1022                                 mr[i].start >> PAGE_SHIFT,
1023                                 mr[i].end >> PAGE_SHIFT,
1024                                 mr[i].page_size_mask == (1<<PG_LEVEL_2M));
1025
1026         early_ioremap_page_table_range_init(pgd_base);
1027
1028         load_cr3(swapper_pg_dir);
1029
1030         __flush_tlb_all();
1031
1032         if (!after_init_bootmem)
1033                 reserve_early(table_start << PAGE_SHIFT,
1034                                  table_end << PAGE_SHIFT, "PGTABLE");
1035
1036         if (!after_init_bootmem)
1037                 early_memtest(start, end);
1038
1039         return end >> PAGE_SHIFT;
1040 }
1041
1042
1043 /*
1044  * paging_init() sets up the page tables - note that the first 8MB are
1045  * already mapped by head.S.
1046  *
1047  * This routines also unmaps the page at virtual kernel address 0, so
1048  * that we can trap those pesky NULL-reference errors in the kernel.
1049  */
1050 void __init paging_init(void)
1051 {
1052         pagetable_init();
1053
1054         __flush_tlb_all();
1055
1056         kmap_init();
1057
1058         /*
1059          * NOTE: at this point the bootmem allocator is fully available.
1060          */
1061         sparse_init();
1062         zone_sizes_init();
1063 }
1064
1065 /*
1066  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
1067  * and also on some strange 486's. All 586+'s are OK. This used to involve
1068  * black magic jumps to work around some nasty CPU bugs, but fortunately the
1069  * switch to using exceptions got rid of all that.
1070  */
1071 static void __init test_wp_bit(void)
1072 {
1073         printk(KERN_INFO
1074   "Checking if this processor honours the WP bit even in supervisor mode...");
1075
1076         /* Any page-aligned address will do, the test is non-destructive */
1077         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
1078         boot_cpu_data.wp_works_ok = do_test_wp_bit();
1079         clear_fixmap(FIX_WP_TEST);
1080
1081         if (!boot_cpu_data.wp_works_ok) {
1082                 printk(KERN_CONT "No.\n");
1083 #ifdef CONFIG_X86_WP_WORKS_OK
1084                 panic(
1085   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
1086 #endif
1087         } else {
1088                 printk(KERN_CONT "Ok.\n");
1089         }
1090 }
1091
1092 static struct kcore_list kcore_mem, kcore_vmalloc;
1093
1094 void __init mem_init(void)
1095 {
1096         int codesize, reservedpages, datasize, initsize;
1097         int tmp;
1098
1099         pci_iommu_alloc();
1100
1101 #ifdef CONFIG_FLATMEM
1102         BUG_ON(!mem_map);
1103 #endif
1104         /* this will put all low memory onto the freelists */
1105         totalram_pages += free_all_bootmem();
1106
1107         reservedpages = 0;
1108         for (tmp = 0; tmp < max_low_pfn; tmp++)
1109                 /*
1110                  * Only count reserved RAM pages:
1111                  */
1112                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
1113                         reservedpages++;
1114
1115         set_highmem_pages_init();
1116
1117         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
1118         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
1119         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
1120
1121         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
1122         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
1123                    VMALLOC_END-VMALLOC_START);
1124
1125         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
1126                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
1127                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
1128                 num_physpages << (PAGE_SHIFT-10),
1129                 codesize >> 10,
1130                 reservedpages << (PAGE_SHIFT-10),
1131                 datasize >> 10,
1132                 initsize >> 10,
1133                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
1134                );
1135
1136         printk(KERN_INFO "virtual kernel memory layout:\n"
1137                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1138 #ifdef CONFIG_HIGHMEM
1139                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1140 #endif
1141                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1142                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1143                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1144                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1145                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
1146                 FIXADDR_START, FIXADDR_TOP,
1147                 (FIXADDR_TOP - FIXADDR_START) >> 10,
1148
1149 #ifdef CONFIG_HIGHMEM
1150                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
1151                 (LAST_PKMAP*PAGE_SIZE) >> 10,
1152 #endif
1153
1154                 VMALLOC_START, VMALLOC_END,
1155                 (VMALLOC_END - VMALLOC_START) >> 20,
1156
1157                 (unsigned long)__va(0), (unsigned long)high_memory,
1158                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
1159
1160                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
1161                 ((unsigned long)&__init_end -
1162                  (unsigned long)&__init_begin) >> 10,
1163
1164                 (unsigned long)&_etext, (unsigned long)&_edata,
1165                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
1166
1167                 (unsigned long)&_text, (unsigned long)&_etext,
1168                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
1169
1170         /*
1171          * Check boundaries twice: Some fundamental inconsistencies can
1172          * be detected at build time already.
1173          */
1174 #define __FIXADDR_TOP (-PAGE_SIZE)
1175 #ifdef CONFIG_HIGHMEM
1176         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
1177         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
1178 #endif
1179 #define high_memory (-128UL << 20)
1180         BUILD_BUG_ON(VMALLOC_START                      >= VMALLOC_END);
1181 #undef high_memory
1182 #undef __FIXADDR_TOP
1183
1184 #ifdef CONFIG_HIGHMEM
1185         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
1186         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
1187 #endif
1188         BUG_ON(VMALLOC_START                            >= VMALLOC_END);
1189         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
1190
1191         if (boot_cpu_data.wp_works_ok < 0)
1192                 test_wp_bit();
1193
1194         save_pg_dir();
1195         zap_low_mappings();
1196 }
1197
1198 #ifdef CONFIG_MEMORY_HOTPLUG
1199 int arch_add_memory(int nid, u64 start, u64 size)
1200 {
1201         struct pglist_data *pgdata = NODE_DATA(nid);
1202         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1203         unsigned long start_pfn = start >> PAGE_SHIFT;
1204         unsigned long nr_pages = size >> PAGE_SHIFT;
1205
1206         return __add_pages(nid, zone, start_pfn, nr_pages);
1207 }
1208 #endif
1209
1210 /*
1211  * This function cannot be __init, since exceptions don't work in that
1212  * section.  Put this after the callers, so that it cannot be inlined.
1213  */
1214 static noinline int do_test_wp_bit(void)
1215 {
1216         char tmp_reg;
1217         int flag;
1218
1219         __asm__ __volatile__(
1220                 "       movb %0, %1     \n"
1221                 "1:     movb %1, %0     \n"
1222                 "       xorl %2, %2     \n"
1223                 "2:                     \n"
1224                 _ASM_EXTABLE(1b,2b)
1225                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1226                  "=q" (tmp_reg),
1227                  "=r" (flag)
1228                 :"2" (1)
1229                 :"memory");
1230
1231         return flag;
1232 }
1233
1234 #ifdef CONFIG_DEBUG_RODATA
1235 const int rodata_test_data = 0xC3;
1236 EXPORT_SYMBOL_GPL(rodata_test_data);
1237
1238 void mark_rodata_ro(void)
1239 {
1240         unsigned long start = PFN_ALIGN(_text);
1241         unsigned long size = PFN_ALIGN(_etext) - start;
1242
1243 #ifndef CONFIG_DYNAMIC_FTRACE
1244         /* Dynamic tracing modifies the kernel text section */
1245         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1246         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1247                 size >> 10);
1248
1249 #ifdef CONFIG_CPA_DEBUG
1250         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1251                 start, start+size);
1252         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1253
1254         printk(KERN_INFO "Testing CPA: write protecting again\n");
1255         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1256 #endif
1257 #endif /* CONFIG_DYNAMIC_FTRACE */
1258
1259         start += size;
1260         size = (unsigned long)__end_rodata - start;
1261         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1262         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1263                 size >> 10);
1264         rodata_test();
1265
1266 #ifdef CONFIG_CPA_DEBUG
1267         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1268         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1269
1270         printk(KERN_INFO "Testing CPA: write protecting again\n");
1271         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1272 #endif
1273 }
1274 #endif
1275
1276 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1277                                    int flags)
1278 {
1279         return reserve_bootmem(phys, len, flags);
1280 }