git.oblomov.eu Git - linux-2.6/blob - 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 #include <asm/smp.h>
  53
  54 unsigned int __VMALLOC_RESERVE = 128 << 20;
  55
  56 unsigned long max_low_pfn_mapped;
  57 unsigned long max_pfn_mapped;
  58
  59 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  60 unsigned long highstart_pfn, highend_pfn;
  61
  62 static noinline int do_test_wp_bit(void);
  63
  64
  65 static unsigned long __initdata table_start;
  66 static unsigned long __meminitdata table_end;
  67 static unsigned long __meminitdata table_top;
  68
  69 static int __initdata after_init_bootmem;
  70
  71 static __init void *alloc_low_page(void)
  72 {
  73         unsigned long pfn = table_end++;
  74         void *adr;
  75
  76         if (pfn >= table_top)
  77                 panic("alloc_low_page: ran out of memory");
  78
  79         adr = __va(pfn * PAGE_SIZE);
  80         memset(adr, 0, PAGE_SIZE);
  81         return adr;
  82 }
  83
  84 /*
  85  * Creates a middle page table and puts a pointer to it in the
  86  * given global directory entry. This only returns the gd entry
  87  * in non-PAE compilation mode, since the middle layer is folded.
  88  */
  89 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  90 {
  91         pud_t *pud;
  92         pmd_t *pmd_table;
  93
  94 #ifdef CONFIG_X86_PAE
  95         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();
 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                 return pmd_table;
 106         }
 107 #endif
 108         pud = pud_offset(pgd, 0);
 109         pmd_table = pmd_offset(pud, 0);
 110
 111         return pmd_table;
 112 }
 113
 114 /*
 115  * Create a page table and place a pointer to it in a middle page
 116  * directory entry:
 117  */
 118 static pte_t * __init one_page_table_init(pmd_t *pmd)
 119 {
 120         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 121                 pte_t *page_table = NULL;
 122
 123                 if (after_init_bootmem) {
 124 #ifdef CONFIG_DEBUG_PAGEALLOC
 125                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 126 #endif
 127                         if (!page_table)
 128                                 page_table =
 129                                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 130                 } else
 131                         page_table = (pte_t *)alloc_low_page();
 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 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
 142                                            unsigned long vaddr, pte_t *lastpte)
 143 {
 144 #ifdef CONFIG_HIGHMEM
 145         /*
 146          * Something (early fixmap) may already have put a pte
 147          * page here, which causes the page table allocation
 148          * to become nonlinear. Attempt to fix it, and if it
 149          * is still nonlinear then we have to bug.
 150          */
 151         int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
 152         int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
 153
 154         if (pmd_idx_kmap_begin != pmd_idx_kmap_end
 155             && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
 156             && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
 157             && ((__pa(pte) >> PAGE_SHIFT) < table_start
 158                 || (__pa(pte) >> PAGE_SHIFT) >= table_end)) {
 159                 pte_t *newpte;
 160                 int i;
 161
 162                 BUG_ON(after_init_bootmem);
 163                 newpte = alloc_low_page();
 164                 for (i = 0; i < PTRS_PER_PTE; i++)
 165                         set_pte(newpte + i, pte[i]);
 166
 167                 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
 168                 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
 169                 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
 170                 __flush_tlb_all();
 171
 172                 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
 173                 pte = newpte;
 174         }
 175         BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
 176                && vaddr > fix_to_virt(FIX_KMAP_END)
 177                && lastpte && lastpte + PTRS_PER_PTE != pte);
 178 #endif
 179         return pte;
 180 }
 181
 182 /*
 183  * This function initializes a certain range of kernel virtual memory
 184  * with new bootmem page tables, everywhere page tables are missing in
 185  * the given range.
 186  *
 187  * NOTE: The pagetables are allocated contiguous on the physical space
 188  * so we can cache the place of the first one and move around without
 189  * checking the pgd every time.
 190  */
 191 static void __init
 192 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 193 {
 194         int pgd_idx, pmd_idx;
 195         unsigned long vaddr;
 196         pgd_t *pgd;
 197         pmd_t *pmd;
 198         pte_t *pte = NULL;
 199
 200         vaddr = start;
 201         pgd_idx = pgd_index(vaddr);
 202         pmd_idx = pmd_index(vaddr);
 203         pgd = pgd_base + pgd_idx;
 204
 205         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 206                 pmd = one_md_table_init(pgd);
 207                 pmd = pmd + pmd_index(vaddr);
 208                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 209                                                         pmd++, pmd_idx++) {
 210                         pte = page_table_kmap_check(one_page_table_init(pmd),
 211                                                     pmd, vaddr, pte);
 212
 213                         vaddr += PMD_SIZE;
 214                 }
 215                 pmd_idx = 0;
 216         }
 217 }
 218
 219 static inline int is_kernel_text(unsigned long addr)
 220 {
 221         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 222                 return 1;
 223         return 0;
 224 }
 225
 226 /*
 227  * This maps the physical memory to kernel virtual address space, a total
 228  * of max_low_pfn pages, by creating page tables starting from address
 229  * PAGE_OFFSET:
 230  */
 231 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
 232                                                 unsigned long start_pfn,
 233                                                 unsigned long end_pfn,
 234                                                 int use_pse)
 235 {
 236         int pgd_idx, pmd_idx, pte_ofs;
 237         unsigned long pfn;
 238         pgd_t *pgd;
 239         pmd_t *pmd;
 240         pte_t *pte;
 241         unsigned pages_2m, pages_4k;
 242         int mapping_iter;
 243
 244         /*
 245          * First iteration will setup identity mapping using large/small pages
 246          * based on use_pse, with other attributes same as set by
 247          * the early code in head_32.S
 248          *
 249          * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
 250          * as desired for the kernel identity mapping.
 251          *
 252          * This two pass mechanism conforms to the TLB app note which says:
 253          *
 254          *     "Software should not write to a paging-structure entry in a way
 255          *      that would change, for any linear address, both the page size
 256          *      and either the page frame or attributes."
 257          */
 258         mapping_iter = 1;
 259
 260         if (!cpu_has_pse)
 261                 use_pse = 0;
 262
 263 repeat:
 264         pages_2m = pages_4k = 0;
 265         pfn = start_pfn;
 266         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 267         pgd = pgd_base + pgd_idx;
 268         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 269                 pmd = one_md_table_init(pgd);
 270
 271                 if (pfn >= end_pfn)
 272                         continue;
 273 #ifdef CONFIG_X86_PAE
 274                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 275                 pmd += pmd_idx;
 276 #else
 277                 pmd_idx = 0;
 278 #endif
 279                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 280                      pmd++, pmd_idx++) {
 281                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 282
 283                         /*
 284                          * Map with big pages if possible, otherwise
 285                          * create normal page tables:
 286                          */
 287                         if (use_pse) {
 288                                 unsigned int addr2;
 289                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 290                                 /*
 291                                  * first pass will use the same initial
 292                                  * identity mapping attribute + _PAGE_PSE.
 293                                  */
 294                                 pgprot_t init_prot =
 295                                         __pgprot(PTE_IDENT_ATTR |
 296                                                  _PAGE_PSE);
 297
 298                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 299                                         PAGE_OFFSET + PAGE_SIZE-1;
 300
 301                                 if (is_kernel_text(addr) ||
 302                                     is_kernel_text(addr2))
 303                                         prot = PAGE_KERNEL_LARGE_EXEC;
 304
 305                                 pages_2m++;
 306                                 if (mapping_iter == 1)
 307                                         set_pmd(pmd, pfn_pmd(pfn, init_prot));
 308                                 else
 309                                         set_pmd(pmd, pfn_pmd(pfn, prot));
 310
 311                                 pfn += PTRS_PER_PTE;
 312                                 continue;
 313                         }
 314                         pte = one_page_table_init(pmd);
 315
 316                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 317                         pte += pte_ofs;
 318                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 319                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 320                                 pgprot_t prot = PAGE_KERNEL;
 321                                 /*
 322                                  * first pass will use the same initial
 323                                  * identity mapping attribute.
 324                                  */
 325                                 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 326
 327                                 if (is_kernel_text(addr))
 328                                         prot = PAGE_KERNEL_EXEC;
 329
 330                                 pages_4k++;
 331                                 if (mapping_iter == 1)
 332                                         set_pte(pte, pfn_pte(pfn, init_prot));
 333                                 else
 334                                         set_pte(pte, pfn_pte(pfn, prot));
 335                         }
 336                 }
 337         }
 338         if (mapping_iter == 1) {
 339                 /*
 340                  * update direct mapping page count only in the first
 341                  * iteration.
 342                  */
 343                 update_page_count(PG_LEVEL_2M, pages_2m);
 344                 update_page_count(PG_LEVEL_4K, pages_4k);
 345
 346                 /*
 347                  * local global flush tlb, which will flush the previous
 348                  * mappings present in both small and large page TLB's.
 349                  */
 350                 __flush_tlb_all();
 351
 352                 /*
 353                  * Second iteration will set the actual desired PTE attributes.
 354                  */
 355                 mapping_iter = 2;
 356                 goto repeat;
 357         }
 358 }
 359
 360 /*
 361  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 362  * is valid. The argument is a physical page number.
 363  *
 364  *
 365  * On x86, access has to be given to the first megabyte of ram because that area
 366  * contains bios code and data regions used by X and dosemu and similar apps.
 367  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 368  * mmio resources as well as potential bios/acpi data regions.
 369  */
 370 int devmem_is_allowed(unsigned long pagenr)
 371 {
 372         if (pagenr <= 256)
 373                 return 1;
 374         if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
 375                 return 0;
 376         if (!page_is_ram(pagenr))
 377                 return 1;
 378         return 0;
 379 }
 380
 381 pte_t *kmap_pte;
 382 pgprot_t kmap_prot;
 383
 384 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 385 {
 386         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 387                         vaddr), vaddr), vaddr);
 388 }
 389
 390 static void __init kmap_init(void)
 391 {
 392         unsigned long kmap_vstart;
 393
 394         /*
 395          * Cache the first kmap pte:
 396          */
 397         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 398         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 399
 400         kmap_prot = PAGE_KERNEL;
 401 }
 402
 403 #ifdef CONFIG_HIGHMEM
 404 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 405 {
 406         unsigned long vaddr;
 407         pgd_t *pgd;
 408         pud_t *pud;
 409         pmd_t *pmd;
 410         pte_t *pte;
 411
 412         vaddr = PKMAP_BASE;
 413         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 414
 415         pgd = swapper_pg_dir + pgd_index(vaddr);
 416         pud = pud_offset(pgd, vaddr);
 417         pmd = pmd_offset(pud, vaddr);
 418         pte = pte_offset_kernel(pmd, vaddr);
 419         pkmap_page_table = pte;
 420 }
 421
 422 static void __init add_one_highpage_init(struct page *page, int pfn)
 423 {
 424         ClearPageReserved(page);
 425         init_page_count(page);
 426         __free_page(page);
 427         totalhigh_pages++;
 428 }
 429
 430 struct add_highpages_data {
 431         unsigned long start_pfn;
 432         unsigned long end_pfn;
 433 };
 434
 435 static int __init add_highpages_work_fn(unsigned long start_pfn,
 436                                          unsigned long end_pfn, void *datax)
 437 {
 438         int node_pfn;
 439         struct page *page;
 440         unsigned long final_start_pfn, final_end_pfn;
 441         struct add_highpages_data *data;
 442
 443         data = (struct add_highpages_data *)datax;
 444
 445         final_start_pfn = max(start_pfn, data->start_pfn);
 446         final_end_pfn = min(end_pfn, data->end_pfn);
 447         if (final_start_pfn >= final_end_pfn)
 448                 return 0;
 449
 450         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 451              node_pfn++) {
 452                 if (!pfn_valid(node_pfn))
 453                         continue;
 454                 page = pfn_to_page(node_pfn);
 455                 add_one_highpage_init(page, node_pfn);
 456         }
 457
 458         return 0;
 459
 460 }
 461
 462 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 463                                               unsigned long end_pfn)
 464 {
 465         struct add_highpages_data data;
 466
 467         data.start_pfn = start_pfn;
 468         data.end_pfn = end_pfn;
 469
 470         work_with_active_regions(nid, add_highpages_work_fn, &data);
 471 }
 472
 473 #ifndef CONFIG_NUMA
 474 static void __init set_highmem_pages_init(void)
 475 {
 476         add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
 477
 478         totalram_pages += totalhigh_pages;
 479 }
 480 #endif /* !CONFIG_NUMA */
 481
 482 #else
 483 static inline void permanent_kmaps_init(pgd_t *pgd_base)
 484 {
 485 }
 486 static inline void set_highmem_pages_init(void)
 487 {
 488 }
 489 #endif /* CONFIG_HIGHMEM */
 490
 491 void __init native_pagetable_setup_start(pgd_t *base)
 492 {
 493         unsigned long pfn, va;
 494         pgd_t *pgd;
 495         pud_t *pud;
 496         pmd_t *pmd;
 497         pte_t *pte;
 498
 499         /*
 500          * Remove any mappings which extend past the end of physical
 501          * memory from the boot time page table:
 502          */
 503         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 504                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 505                 pgd = base + pgd_index(va);
 506                 if (!pgd_present(*pgd))
 507                         break;
 508
 509                 pud = pud_offset(pgd, va);
 510                 pmd = pmd_offset(pud, va);
 511                 if (!pmd_present(*pmd))
 512                         break;
 513
 514                 pte = pte_offset_kernel(pmd, va);
 515                 if (!pte_present(*pte))
 516                         break;
 517
 518                 pte_clear(NULL, va, pte);
 519         }
 520         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 521 }
 522
 523 void __init native_pagetable_setup_done(pgd_t *base)
 524 {
 525 }
 526
 527 /*
 528  * Build a proper pagetable for the kernel mappings.  Up until this
 529  * point, we've been running on some set of pagetables constructed by
 530  * the boot process.
 531  *
 532  * If we're booting on native hardware, this will be a pagetable
 533  * constructed in arch/x86/kernel/head_32.S.  The root of the
 534  * pagetable will be swapper_pg_dir.
 535  *
 536  * If we're booting paravirtualized under a hypervisor, then there are
 537  * more options: we may already be running PAE, and the pagetable may
 538  * or may not be based in swapper_pg_dir.  In any case,
 539  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 540  * appropriately for the rest of the initialization to work.
 541  *
 542  * In general, pagetable_init() assumes that the pagetable may already
 543  * be partially populated, and so it avoids stomping on any existing
 544  * mappings.
 545  */
 546 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
 547 {
 548         unsigned long vaddr, end;
 549
 550         /*
 551          * Fixed mappings, only the page table structure has to be
 552          * created - mappings will be set by set_fixmap():
 553          */
 554         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 555         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 556         page_table_range_init(vaddr, end, pgd_base);
 557         early_ioremap_reset();
 558 }
 559
 560 static void __init pagetable_init(void)
 561 {
 562         pgd_t *pgd_base = swapper_pg_dir;
 563
 564         permanent_kmaps_init(pgd_base);
 565 }
 566
 567 #ifdef CONFIG_ACPI_SLEEP
 568 /*
 569  * ACPI suspend needs this for resume, because things like the intel-agp
 570  * driver might have split up a kernel 4MB mapping.
 571  */
 572 char swsusp_pg_dir[PAGE_SIZE]
 573         __attribute__ ((aligned(PAGE_SIZE)));
 574
 575 static inline void save_pg_dir(void)
 576 {
 577         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 578 }
 579 #else /* !CONFIG_ACPI_SLEEP */
 580 static inline void save_pg_dir(void)
 581 {
 582 }
 583 #endif /* !CONFIG_ACPI_SLEEP */
 584
 585 void zap_low_mappings(void)
 586 {
 587         int i;
 588
 589         /*
 590          * Zap initial low-memory mappings.
 591          *
 592          * Note that "pgd_clear()" doesn't do it for
 593          * us, because pgd_clear() is a no-op on i386.
 594          */
 595         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 596 #ifdef CONFIG_X86_PAE
 597                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 598 #else
 599                 set_pgd(swapper_pg_dir+i, __pgd(0));
 600 #endif
 601         }
 602         flush_tlb_all();
 603 }
 604
 605 int nx_enabled;
 606
 607 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 608 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 609
 610 #ifdef CONFIG_X86_PAE
 611
 612 static int disable_nx __initdata;
 613
 614 /*
 615  * noexec = on|off
 616  *
 617  * Control non executable mappings.
 618  *
 619  * on      Enable
 620  * off     Disable
 621  */
 622 static int __init noexec_setup(char *str)
 623 {
 624         if (!str || !strcmp(str, "on")) {
 625                 if (cpu_has_nx) {
 626                         __supported_pte_mask |= _PAGE_NX;
 627                         disable_nx = 0;
 628                 }
 629         } else {
 630                 if (!strcmp(str, "off")) {
 631                         disable_nx = 1;
 632                         __supported_pte_mask &= ~_PAGE_NX;
 633                 } else {
 634                         return -EINVAL;
 635                 }
 636         }
 637
 638         return 0;
 639 }
 640 early_param("noexec", noexec_setup);
 641
 642 static void __init set_nx(void)
 643 {
 644         unsigned int v[4], l, h;
 645
 646         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 647                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 648
 649                 if ((v[3] & (1 << 20)) && !disable_nx) {
 650                         rdmsr(MSR_EFER, l, h);
 651                         l |= EFER_NX;
 652                         wrmsr(MSR_EFER, l, h);
 653                         nx_enabled = 1;
 654                         __supported_pte_mask |= _PAGE_NX;
 655                 }
 656         }
 657 }
 658 #endif
 659
 660 /* user-defined highmem size */
 661 static unsigned int highmem_pages = -1;
 662
 663 /*
 664  * highmem=size forces highmem to be exactly 'size' bytes.
 665  * This works even on boxes that have no highmem otherwise.
 666  * This also works to reduce highmem size on bigger boxes.
 667  */
 668 static int __init parse_highmem(char *arg)
 669 {
 670         if (!arg)
 671                 return -EINVAL;
 672
 673         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 674         return 0;
 675 }
 676 early_param("highmem", parse_highmem);
 677
 678 /*
 679  * Determine low and high memory ranges:
 680  */
 681 void __init find_low_pfn_range(void)
 682 {
 683         /* it could update max_pfn */
 684
 685         /* max_low_pfn is 0, we already have early_res support */
 686
 687         max_low_pfn = max_pfn;
 688         if (max_low_pfn > MAXMEM_PFN) {
 689                 if (highmem_pages == -1)
 690                         highmem_pages = max_pfn - MAXMEM_PFN;
 691                 if (highmem_pages + MAXMEM_PFN < max_pfn)
 692                         max_pfn = MAXMEM_PFN + highmem_pages;
 693                 if (highmem_pages + MAXMEM_PFN > max_pfn) {
 694                         printk(KERN_WARNING "only %luMB highmem pages "
 695                                 "available, ignoring highmem size of %uMB.\n",
 696                                 pages_to_mb(max_pfn - MAXMEM_PFN),
 697                                 pages_to_mb(highmem_pages));
 698                         highmem_pages = 0;
 699                 }
 700                 max_low_pfn = MAXMEM_PFN;
 701 #ifndef CONFIG_HIGHMEM
 702                 /* Maximum memory usable is what is directly addressable */
 703                 printk(KERN_WARNING "Warning only %ldMB will be used.\n",
 704                                         MAXMEM>>20);
 705                 if (max_pfn > MAX_NONPAE_PFN)
 706                         printk(KERN_WARNING
 707                                  "Use a HIGHMEM64G enabled kernel.\n");
 708                 else
 709                         printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 710                 max_pfn = MAXMEM_PFN;
 711 #else /* !CONFIG_HIGHMEM */
 712 #ifndef CONFIG_HIGHMEM64G
 713                 if (max_pfn > MAX_NONPAE_PFN) {
 714                         max_pfn = MAX_NONPAE_PFN;
 715                         printk(KERN_WARNING "Warning only 4GB will be used."
 716                                 "Use a HIGHMEM64G enabled kernel.\n");
 717                 }
 718 #endif /* !CONFIG_HIGHMEM64G */
 719 #endif /* !CONFIG_HIGHMEM */
 720         } else {
 721                 if (highmem_pages == -1)
 722                         highmem_pages = 0;
 723 #ifdef CONFIG_HIGHMEM
 724                 if (highmem_pages >= max_pfn) {
 725                         printk(KERN_ERR "highmem size specified (%uMB) is "
 726                                 "bigger than pages available (%luMB)!.\n",
 727                                 pages_to_mb(highmem_pages),
 728                                 pages_to_mb(max_pfn));
 729                         highmem_pages = 0;
 730                 }
 731                 if (highmem_pages) {
 732                         if (max_low_pfn - highmem_pages <
 733                             64*1024*1024/PAGE_SIZE){
 734                                 printk(KERN_ERR "highmem size %uMB results in "
 735                                 "smaller than 64MB lowmem, ignoring it.\n"
 736                                         , pages_to_mb(highmem_pages));
 737                                 highmem_pages = 0;
 738                         }
 739                         max_low_pfn -= highmem_pages;
 740                 }
 741 #else
 742                 if (highmem_pages)
 743                         printk(KERN_ERR "ignoring highmem size on non-highmem"
 744                                         " kernel!\n");
 745 #endif
 746         }
 747 }
 748
 749 #ifndef CONFIG_NEED_MULTIPLE_NODES
 750 void __init initmem_init(unsigned long start_pfn,
 751                                   unsigned long end_pfn)
 752 {
 753 #ifdef CONFIG_HIGHMEM
 754         highstart_pfn = highend_pfn = max_pfn;
 755         if (max_pfn > max_low_pfn)
 756                 highstart_pfn = max_low_pfn;
 757         memory_present(0, 0, highend_pfn);
 758         e820_register_active_regions(0, 0, highend_pfn);
 759         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 760                 pages_to_mb(highend_pfn - highstart_pfn));
 761         num_physpages = highend_pfn;
 762         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 763 #else
 764         memory_present(0, 0, max_low_pfn);
 765         e820_register_active_regions(0, 0, max_low_pfn);
 766         num_physpages = max_low_pfn;
 767         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 768 #endif
 769 #ifdef CONFIG_FLATMEM
 770         max_mapnr = num_physpages;
 771 #endif
 772         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 773                         pages_to_mb(max_low_pfn));
 774
 775         setup_bootmem_allocator();
 776 }
 777 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 778
 779 static void __init zone_sizes_init(void)
 780 {
 781         unsigned long max_zone_pfns[MAX_NR_ZONES];
 782         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 783         max_zone_pfns[ZONE_DMA] =
 784                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 785         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 786 #ifdef CONFIG_HIGHMEM
 787         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 788 #endif
 789
 790         free_area_init_nodes(max_zone_pfns);
 791 }
 792
 793 void __init setup_bootmem_allocator(void)
 794 {
 795         int i;
 796         unsigned long bootmap_size, bootmap;
 797         /*
 798          * Initialize the boot-time allocator (with low memory only):
 799          */
 800         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 801         bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
 802                                  max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 803                                  PAGE_SIZE);
 804         if (bootmap == -1L)
 805                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 806         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 807
 808         /* don't touch min_low_pfn */
 809         bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
 810                                          min_low_pfn, max_low_pfn);
 811         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 812                  max_pfn_mapped<<PAGE_SHIFT);
 813         printk(KERN_INFO "  low ram: %08lx - %08lx\n",
 814                  min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
 815         printk(KERN_INFO "  bootmap %08lx - %08lx\n",
 816                  bootmap, bootmap + bootmap_size);
 817         for_each_online_node(i)
 818                 free_bootmem_with_active_regions(i, max_low_pfn);
 819         early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
 820
 821         after_init_bootmem = 1;
 822 }
 823
 824 static void __init find_early_table_space(unsigned long end, int use_pse)
 825 {
 826         unsigned long puds, pmds, ptes, tables, start;
 827
 828         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
 829         tables = PAGE_ALIGN(puds * sizeof(pud_t));
 830
 831         pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
 832         tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
 833
 834         if (use_pse) {
 835                 unsigned long extra;
 836
 837                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
 838                 extra += PMD_SIZE;
 839                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 840         } else
 841                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
 842
 843         tables += PAGE_ALIGN(ptes * sizeof(pte_t));
 844
 845         /* for fixmap */
 846         tables += PAGE_ALIGN(__end_of_fixed_addresses * sizeof(pte_t));
 847
 848         /*
 849          * RED-PEN putting page tables only on node 0 could
 850          * cause a hotspot and fill up ZONE_DMA. The page tables
 851          * need roughly 0.5KB per GB.
 852          */
 853         start = 0x7000;
 854         table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
 855                                         tables, PAGE_SIZE);
 856         if (table_start == -1UL)
 857                 panic("Cannot find space for the kernel page tables");
 858
 859         table_start >>= PAGE_SHIFT;
 860         table_end = table_start;
 861         table_top = table_start + (tables>>PAGE_SHIFT);
 862
 863         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 864                 end, table_start << PAGE_SHIFT,
 865                 (table_start << PAGE_SHIFT) + tables);
 866 }
 867
 868 unsigned long __init_refok init_memory_mapping(unsigned long start,
 869                                                 unsigned long end)
 870 {
 871         pgd_t *pgd_base = swapper_pg_dir;
 872         unsigned long start_pfn, end_pfn;
 873         unsigned long big_page_start;
 874 #ifdef CONFIG_DEBUG_PAGEALLOC
 875         /*
 876          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 877          * This will simplify cpa(), which otherwise needs to support splitting
 878          * large pages into small in interrupt context, etc.
 879          */
 880         int use_pse = 0;
 881 #else
 882         int use_pse = cpu_has_pse;
 883 #endif
 884
 885         /*
 886          * Find space for the kernel direct mapping tables.
 887          */
 888         if (!after_init_bootmem)
 889                 find_early_table_space(end, use_pse);
 890
 891 #ifdef CONFIG_X86_PAE
 892         set_nx();
 893         if (nx_enabled)
 894                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 895 #endif
 896
 897         /* Enable PSE if available */
 898         if (cpu_has_pse)
 899                 set_in_cr4(X86_CR4_PSE);
 900
 901         /* Enable PGE if available */
 902         if (cpu_has_pge) {
 903                 set_in_cr4(X86_CR4_PGE);
 904                 __supported_pte_mask |= _PAGE_GLOBAL;
 905         }
 906
 907         /*
 908          * Don't use a large page for the first 2/4MB of memory
 909          * because there are often fixed size MTRRs in there
 910          * and overlapping MTRRs into large pages can cause
 911          * slowdowns.
 912          */
 913         big_page_start = PMD_SIZE;
 914
 915         if (start < big_page_start) {
 916                 start_pfn = start >> PAGE_SHIFT;
 917                 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
 918         } else {
 919                 /* head is not big page alignment ? */
 920                 start_pfn = start >> PAGE_SHIFT;
 921                 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 922                                  << (PMD_SHIFT - PAGE_SHIFT);
 923         }
 924         if (start_pfn < end_pfn)
 925                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
 926
 927         /* big page range */
 928         start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 929                          << (PMD_SHIFT - PAGE_SHIFT);
 930         if (start_pfn < (big_page_start >> PAGE_SHIFT))
 931                 start_pfn =  big_page_start >> PAGE_SHIFT;
 932         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 933         if (start_pfn < end_pfn)
 934                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
 935                                              use_pse);
 936
 937         /* tail is not big page alignment ? */
 938         start_pfn = end_pfn;
 939         if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
 940                 end_pfn = end >> PAGE_SHIFT;
 941                 if (start_pfn < end_pfn)
 942                         kernel_physical_mapping_init(pgd_base, start_pfn,
 943                                                          end_pfn, 0);
 944         }
 945
 946         early_ioremap_page_table_range_init(pgd_base);
 947
 948         load_cr3(swapper_pg_dir);
 949
 950         __flush_tlb_all();
 951
 952         if (!after_init_bootmem)
 953                 reserve_early(table_start << PAGE_SHIFT,
 954                                  table_end << PAGE_SHIFT, "PGTABLE");
 955
 956         if (!after_init_bootmem)
 957                 early_memtest(start, end);
 958
 959         return end >> PAGE_SHIFT;
 960 }
 961
 962
 963 /*
 964  * paging_init() sets up the page tables - note that the first 8MB are
 965  * already mapped by head.S.
 966  *
 967  * This routines also unmaps the page at virtual kernel address 0, so
 968  * that we can trap those pesky NULL-reference errors in the kernel.
 969  */
 970 void __init paging_init(void)
 971 {
 972         pagetable_init();
 973
 974         __flush_tlb_all();
 975
 976         kmap_init();
 977
 978         /*
 979          * NOTE: at this point the bootmem allocator is fully available.
 980          */
 981         sparse_init();
 982         zone_sizes_init();
 983 }
 984
 985 /*
 986  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 987  * and also on some strange 486's. All 586+'s are OK. This used to involve
 988  * black magic jumps to work around some nasty CPU bugs, but fortunately the
 989  * switch to using exceptions got rid of all that.
 990  */
 991 static void __init test_wp_bit(void)
 992 {
 993         printk(KERN_INFO
 994   "Checking if this processor honours the WP bit even in supervisor mode...");
 995
 996         /* Any page-aligned address will do, the test is non-destructive */
 997         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 998         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 999         clear_fixmap(FIX_WP_TEST);
1000
1001         if (!boot_cpu_data.wp_works_ok) {
1002                 printk(KERN_CONT "No.\n");
1003 #ifdef CONFIG_X86_WP_WORKS_OK
1004                 panic(
1005   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
1006 #endif
1007         } else {
1008                 printk(KERN_CONT "Ok.\n");
1009         }
1010 }
1011
1012 static struct kcore_list kcore_mem, kcore_vmalloc;
1013
1014 void __init mem_init(void)
1015 {
1016         int codesize, reservedpages, datasize, initsize;
1017         int tmp;
1018
1019         pci_iommu_alloc();
1020
1021 #ifdef CONFIG_FLATMEM
1022         BUG_ON(!mem_map);
1023 #endif
1024         /* this will put all low memory onto the freelists */
1025         totalram_pages += free_all_bootmem();
1026
1027         reservedpages = 0;
1028         for (tmp = 0; tmp < max_low_pfn; tmp++)
1029                 /*
1030                  * Only count reserved RAM pages:
1031                  */
1032                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
1033                         reservedpages++;
1034
1035         set_highmem_pages_init();
1036
1037         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
1038         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
1039         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
1040
1041         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
1042         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
1043                    VMALLOC_END-VMALLOC_START);
1044
1045         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
1046                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
1047                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
1048                 num_physpages << (PAGE_SHIFT-10),
1049                 codesize >> 10,
1050                 reservedpages << (PAGE_SHIFT-10),
1051                 datasize >> 10,
1052                 initsize >> 10,
1053                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
1054                );
1055
1056         printk(KERN_INFO "virtual kernel memory layout:\n"
1057                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1058 #ifdef CONFIG_HIGHMEM
1059                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1060 #endif
1061                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1062                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1063                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1064                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1065                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
1066                 FIXADDR_START, FIXADDR_TOP,
1067                 (FIXADDR_TOP - FIXADDR_START) >> 10,
1068
1069 #ifdef CONFIG_HIGHMEM
1070                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
1071                 (LAST_PKMAP*PAGE_SIZE) >> 10,
1072 #endif
1073
1074                 VMALLOC_START, VMALLOC_END,
1075                 (VMALLOC_END - VMALLOC_START) >> 20,
1076
1077                 (unsigned long)__va(0), (unsigned long)high_memory,
1078                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
1079
1080                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
1081                 ((unsigned long)&__init_end -
1082                  (unsigned long)&__init_begin) >> 10,
1083
1084                 (unsigned long)&_etext, (unsigned long)&_edata,
1085                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
1086
1087                 (unsigned long)&_text, (unsigned long)&_etext,
1088                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
1089
1090         /*
1091          * Check boundaries twice: Some fundamental inconsistencies can
1092          * be detected at build time already.
1093          */
1094 #define __FIXADDR_TOP (-PAGE_SIZE)
1095 #ifdef CONFIG_HIGHMEM
1096         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
1097         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
1098 #endif
1099 #define high_memory (-128UL << 20)
1100         BUILD_BUG_ON(VMALLOC_START                      >= VMALLOC_END);
1101 #undef high_memory
1102 #undef __FIXADDR_TOP
1103
1104 #ifdef CONFIG_HIGHMEM
1105         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
1106         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
1107 #endif
1108         BUG_ON(VMALLOC_START                            >= VMALLOC_END);
1109         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
1110
1111         if (boot_cpu_data.wp_works_ok < 0)
1112                 test_wp_bit();
1113
1114         save_pg_dir();
1115         zap_low_mappings();
1116 }
1117
1118 #ifdef CONFIG_MEMORY_HOTPLUG
1119 int arch_add_memory(int nid, u64 start, u64 size)
1120 {
1121         struct pglist_data *pgdata = NODE_DATA(nid);
1122         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1123         unsigned long start_pfn = start >> PAGE_SHIFT;
1124         unsigned long nr_pages = size >> PAGE_SHIFT;
1125
1126         return __add_pages(nid, zone, start_pfn, nr_pages);
1127 }
1128 #endif
1129
1130 /*
1131  * This function cannot be __init, since exceptions don't work in that
1132  * section.  Put this after the callers, so that it cannot be inlined.
1133  */
1134 static noinline int do_test_wp_bit(void)
1135 {
1136         char tmp_reg;
1137         int flag;
1138
1139         __asm__ __volatile__(
1140                 "       movb %0, %1     \n"
1141                 "1:     movb %1, %0     \n"
1142                 "       xorl %2, %2     \n"
1143                 "2:                     \n"
1144                 _ASM_EXTABLE(1b,2b)
1145                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1146                  "=q" (tmp_reg),
1147                  "=r" (flag)
1148                 :"2" (1)
1149                 :"memory");
1150
1151         return flag;
1152 }
1153
1154 #ifdef CONFIG_DEBUG_RODATA
1155 const int rodata_test_data = 0xC3;
1156 EXPORT_SYMBOL_GPL(rodata_test_data);
1157
1158 void mark_rodata_ro(void)
1159 {
1160         unsigned long start = PFN_ALIGN(_text);
1161         unsigned long size = PFN_ALIGN(_etext) - start;
1162
1163 #ifndef CONFIG_DYNAMIC_FTRACE
1164         /* Dynamic tracing modifies the kernel text section */
1165         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1166         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1167                 size >> 10);
1168
1169 #ifdef CONFIG_CPA_DEBUG
1170         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1171                 start, start+size);
1172         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1173
1174         printk(KERN_INFO "Testing CPA: write protecting again\n");
1175         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1176 #endif
1177 #endif /* CONFIG_DYNAMIC_FTRACE */
1178
1179         start += size;
1180         size = (unsigned long)__end_rodata - start;
1181         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1182         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1183                 size >> 10);
1184         rodata_test();
1185
1186 #ifdef CONFIG_CPA_DEBUG
1187         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1188         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1189
1190         printk(KERN_INFO "Testing CPA: write protecting again\n");
1191         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1192 #endif
1193 }
1194 #endif
1195
1196 void free_init_pages(char *what, unsigned long begin, unsigned long end)
1197 {
1198 #ifdef CONFIG_DEBUG_PAGEALLOC
1199         /*
1200          * If debugging page accesses then do not free this memory but
1201          * mark them not present - any buggy init-section access will
1202          * create a kernel page fault:
1203          */
1204         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1205                 begin, PAGE_ALIGN(end));
1206         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1207 #else
1208         unsigned long addr;
1209
1210         /*
1211          * We just marked the kernel text read only above, now that
1212          * we are going to free part of that, we need to make that
1213          * writeable first.
1214          */
1215         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1216
1217         for (addr = begin; addr < end; addr += PAGE_SIZE) {
1218                 ClearPageReserved(virt_to_page(addr));
1219                 init_page_count(virt_to_page(addr));
1220                 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1221                 free_page(addr);
1222                 totalram_pages++;
1223         }
1224         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1225 #endif
1226 }
1227
1228 void free_initmem(void)
1229 {
1230         free_init_pages("unused kernel memory",
1231                         (unsigned long)(&__init_begin),
1232                         (unsigned long)(&__init_end));
1233 }
1234
1235 #ifdef CONFIG_BLK_DEV_INITRD
1236 void free_initrd_mem(unsigned long start, unsigned long end)
1237 {
1238         free_init_pages("initrd memory", start, end);
1239 }
1240 #endif
1241
1242 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1243                                    int flags)
1244 {
1245         return reserve_bootmem(phys, len, flags);
1246 }