arch/x86/mm/init_64.c

   1 /*
   2  *  linux/arch/x86_64/mm/init.c
   3  *
   4  *  Copyright (C) 1995  Linus Torvalds
   5  *  Copyright (C) 2000  Pavel Machek <pavel@suse.cz>
   6  *  Copyright (C) 2002,2003 Andi Kleen <ak@suse.de>
   7  */
   8
   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/swap.h>
  19 #include <linux/smp.h>
  20 #include <linux/init.h>
  21 #include <linux/initrd.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/bootmem.h>
  24 #include <linux/proc_fs.h>
  25 #include <linux/pci.h>
  26 #include <linux/pfn.h>
  27 #include <linux/poison.h>
  28 #include <linux/dma-mapping.h>
  29 #include <linux/module.h>
  30 #include <linux/memory_hotplug.h>
  31 #include <linux/nmi.h>
  32
  33 #include <asm/processor.h>
  34 #include <asm/bios_ebda.h>
  35 #include <asm/system.h>
  36 #include <asm/uaccess.h>
  37 #include <asm/pgtable.h>
  38 #include <asm/pgalloc.h>
  39 #include <asm/dma.h>
  40 #include <asm/fixmap.h>
  41 #include <asm/e820.h>
  42 #include <asm/apic.h>
  43 #include <asm/tlb.h>
  44 #include <asm/mmu_context.h>
  45 #include <asm/proto.h>
  46 #include <asm/smp.h>
  47 #include <asm/sections.h>
  48 #include <asm/kdebug.h>
  49 #include <asm/numa.h>
  50 #include <asm/cacheflush.h>
  51
  52 /*
  53  * end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
  54  * The direct mapping extends to max_pfn_mapped, so that we can directly access
  55  * apertures, ACPI and other tables without having to play with fixmaps.
  56  */
  57 unsigned long max_low_pfn_mapped;
  58 unsigned long max_pfn_mapped;
  59
  60 static unsigned long dma_reserve __initdata;
  61
  62 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  63
  64 int direct_gbpages
  65 #ifdef CONFIG_DIRECT_GBPAGES
  66                                 = 1
  67 #endif
  68 ;
  69
  70 static int __init parse_direct_gbpages_off(char *arg)
  71 {
  72         direct_gbpages = 0;
  73         return 0;
  74 }
  75 early_param("nogbpages", parse_direct_gbpages_off);
  76
  77 static int __init parse_direct_gbpages_on(char *arg)
  78 {
  79         direct_gbpages = 1;
  80         return 0;
  81 }
  82 early_param("gbpages", parse_direct_gbpages_on);
  83
  84 /*
  85  * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
  86  * physical space so we can cache the place of the first one and move
  87  * around without checking the pgd every time.
  88  */
  89
  90 int after_bootmem;
  91
  92 pteval_t __supported_pte_mask __read_mostly = ~_PAGE_IOMAP;
  93 EXPORT_SYMBOL_GPL(__supported_pte_mask);
  94
  95 static int do_not_nx __cpuinitdata;
  96
  97 /*
  98  * noexec=on|off
  99  * Control non-executable mappings for 64-bit processes.
 100  *
 101  * on   Enable (default)
 102  * off  Disable
 103  */
 104 static int __init nonx_setup(char *str)
 105 {
 106         if (!str)
 107                 return -EINVAL;
 108         if (!strncmp(str, "on", 2)) {
 109                 __supported_pte_mask |= _PAGE_NX;
 110                 do_not_nx = 0;
 111         } else if (!strncmp(str, "off", 3)) {
 112                 do_not_nx = 1;
 113                 __supported_pte_mask &= ~_PAGE_NX;
 114         }
 115         return 0;
 116 }
 117 early_param("noexec", nonx_setup);
 118
 119 void __cpuinit check_efer(void)
 120 {
 121         unsigned long efer;
 122
 123         rdmsrl(MSR_EFER, efer);
 124         if (!(efer & EFER_NX) || do_not_nx)
 125                 __supported_pte_mask &= ~_PAGE_NX;
 126 }
 127
 128 int force_personality32;
 129
 130 /*
 131  * noexec32=on|off
 132  * Control non executable heap for 32bit processes.
 133  * To control the stack too use noexec=off
 134  *
 135  * on   PROT_READ does not imply PROT_EXEC for 32-bit processes (default)
 136  * off  PROT_READ implies PROT_EXEC
 137  */
 138 static int __init nonx32_setup(char *str)
 139 {
 140         if (!strcmp(str, "on"))
 141                 force_personality32 &= ~READ_IMPLIES_EXEC;
 142         else if (!strcmp(str, "off"))
 143                 force_personality32 |= READ_IMPLIES_EXEC;
 144         return 1;
 145 }
 146 __setup("noexec32=", nonx32_setup);
 147
 148 /*
 149  * NOTE: This function is marked __ref because it calls __init function
 150  * (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
 151  */
 152 static __ref void *spp_getpage(void)
 153 {
 154         void *ptr;
 155
 156         if (after_bootmem)
 157                 ptr = (void *) get_zeroed_page(GFP_ATOMIC);
 158         else
 159                 ptr = alloc_bootmem_pages(PAGE_SIZE);
 160
 161         if (!ptr || ((unsigned long)ptr & ~PAGE_MASK)) {
 162                 panic("set_pte_phys: cannot allocate page data %s\n",
 163                         after_bootmem ? "after bootmem" : "");
 164         }
 165
 166         pr_debug("spp_getpage %p\n", ptr);
 167
 168         return ptr;
 169 }
 170
 171 void
 172 set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte)
 173 {
 174         pud_t *pud;
 175         pmd_t *pmd;
 176         pte_t *pte;
 177
 178         pud = pud_page + pud_index(vaddr);
 179         if (pud_none(*pud)) {
 180                 pmd = (pmd_t *) spp_getpage();
 181                 pud_populate(&init_mm, pud, pmd);
 182                 if (pmd != pmd_offset(pud, 0)) {
 183                         printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n",
 184                                 pmd, pmd_offset(pud, 0));
 185                         return;
 186                 }
 187         }
 188         pmd = pmd_offset(pud, vaddr);
 189         if (pmd_none(*pmd)) {
 190                 pte = (pte_t *) spp_getpage();
 191                 pmd_populate_kernel(&init_mm, pmd, pte);
 192                 if (pte != pte_offset_kernel(pmd, 0)) {
 193                         printk(KERN_ERR "PAGETABLE BUG #02!\n");
 194                         return;
 195                 }
 196         }
 197
 198         pte = pte_offset_kernel(pmd, vaddr);
 199         set_pte(pte, new_pte);
 200
 201         /*
 202          * It's enough to flush this one mapping.
 203          * (PGE mappings get flushed as well)
 204          */
 205         __flush_tlb_one(vaddr);
 206 }
 207
 208 void
 209 set_pte_vaddr(unsigned long vaddr, pte_t pteval)
 210 {
 211         pgd_t *pgd;
 212         pud_t *pud_page;
 213
 214         pr_debug("set_pte_vaddr %lx to %lx\n", vaddr, native_pte_val(pteval));
 215
 216         pgd = pgd_offset_k(vaddr);
 217         if (pgd_none(*pgd)) {
 218                 printk(KERN_ERR
 219                         "PGD FIXMAP MISSING, it should be setup in head.S!\n");
 220                 return;
 221         }
 222         pud_page = (pud_t*)pgd_page_vaddr(*pgd);
 223         set_pte_vaddr_pud(pud_page, vaddr, pteval);
 224 }
 225
 226 /*
 227  * Create large page table mappings for a range of physical addresses.
 228  */
 229 static void __init __init_extra_mapping(unsigned long phys, unsigned long size,
 230                                                 pgprot_t prot)
 231 {
 232         pgd_t *pgd;
 233         pud_t *pud;
 234         pmd_t *pmd;
 235
 236         BUG_ON((phys & ~PMD_MASK) || (size & ~PMD_MASK));
 237         for (; size; phys += PMD_SIZE, size -= PMD_SIZE) {
 238                 pgd = pgd_offset_k((unsigned long)__va(phys));
 239                 if (pgd_none(*pgd)) {
 240                         pud = (pud_t *) spp_getpage();
 241                         set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE |
 242                                                 _PAGE_USER));
 243                 }
 244                 pud = pud_offset(pgd, (unsigned long)__va(phys));
 245                 if (pud_none(*pud)) {
 246                         pmd = (pmd_t *) spp_getpage();
 247                         set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE |
 248                                                 _PAGE_USER));
 249                 }
 250                 pmd = pmd_offset(pud, phys);
 251                 BUG_ON(!pmd_none(*pmd));
 252                 set_pmd(pmd, __pmd(phys | pgprot_val(prot)));
 253         }
 254 }
 255
 256 void __init init_extra_mapping_wb(unsigned long phys, unsigned long size)
 257 {
 258         __init_extra_mapping(phys, size, PAGE_KERNEL_LARGE);
 259 }
 260
 261 void __init init_extra_mapping_uc(unsigned long phys, unsigned long size)
 262 {
 263         __init_extra_mapping(phys, size, PAGE_KERNEL_LARGE_NOCACHE);
 264 }
 265
 266 /*
 267  * The head.S code sets up the kernel high mapping:
 268  *
 269  *   from __START_KERNEL_map to __START_KERNEL_map + size (== _end-_text)
 270  *
 271  * phys_addr holds the negative offset to the kernel, which is added
 272  * to the compile time generated pmds. This results in invalid pmds up
 273  * to the point where we hit the physaddr 0 mapping.
 274  *
 275  * We limit the mappings to the region from _text to _end.  _end is
 276  * rounded up to the 2MB boundary. This catches the invalid pmds as
 277  * well, as they are located before _text:
 278  */
 279 void __init cleanup_highmap(void)
 280 {
 281         unsigned long vaddr = __START_KERNEL_map;
 282         unsigned long end = roundup((unsigned long)_end, PMD_SIZE) - 1;
 283         pmd_t *pmd = level2_kernel_pgt;
 284         pmd_t *last_pmd = pmd + PTRS_PER_PMD;
 285
 286         for (; pmd < last_pmd; pmd++, vaddr += PMD_SIZE) {
 287                 if (pmd_none(*pmd))
 288                         continue;
 289                 if (vaddr < (unsigned long) _text || vaddr > end)
 290                         set_pmd(pmd, __pmd(0));
 291         }
 292 }
 293
 294 static unsigned long __initdata table_start;
 295 static unsigned long __meminitdata table_end;
 296 static unsigned long __meminitdata table_top;
 297
 298 static __ref void *alloc_low_page(unsigned long *phys)
 299 {
 300         unsigned long pfn = table_end++;
 301         void *adr;
 302
 303         if (after_bootmem) {
 304                 adr = (void *)get_zeroed_page(GFP_ATOMIC);
 305                 *phys = __pa(adr);
 306
 307                 return adr;
 308         }
 309
 310         if (pfn >= table_top)
 311                 panic("alloc_low_page: ran out of memory");
 312
 313         adr = early_memremap(pfn * PAGE_SIZE, PAGE_SIZE);
 314         memset(adr, 0, PAGE_SIZE);
 315         *phys  = pfn * PAGE_SIZE;
 316         return adr;
 317 }
 318
 319 static __ref void unmap_low_page(void *adr)
 320 {
 321         if (after_bootmem)
 322                 return;
 323
 324         early_iounmap(adr, PAGE_SIZE);
 325 }
 326
 327 static unsigned long __meminit
 328 phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end,
 329               pgprot_t prot)
 330 {
 331         unsigned pages = 0;
 332         unsigned long last_map_addr = end;
 333         int i;
 334
 335         pte_t *pte = pte_page + pte_index(addr);
 336
 337         for(i = pte_index(addr); i < PTRS_PER_PTE; i++, addr += PAGE_SIZE, pte++) {
 338
 339                 if (addr >= end) {
 340                         if (!after_bootmem) {
 341                                 for(; i < PTRS_PER_PTE; i++, pte++)
 342                                         set_pte(pte, __pte(0));
 343                         }
 344                         break;
 345                 }
 346
 347                 /*
 348                  * We will re-use the existing mapping.
 349                  * Xen for example has some special requirements, like mapping
 350                  * pagetable pages as RO. So assume someone who pre-setup
 351                  * these mappings are more intelligent.
 352                  */
 353                 if (pte_val(*pte)) {
 354                         pages++;
 355                         continue;
 356                 }
 357
 358                 if (0)
 359                         printk("   pte=%p addr=%lx pte=%016lx\n",
 360                                pte, addr, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL).pte);
 361                 pages++;
 362                 set_pte(pte, pfn_pte(addr >> PAGE_SHIFT, prot));
 363                 last_map_addr = (addr & PAGE_MASK) + PAGE_SIZE;
 364         }
 365
 366         update_page_count(PG_LEVEL_4K, pages);
 367
 368         return last_map_addr;
 369 }
 370
 371 static unsigned long __meminit
 372 phys_pte_update(pmd_t *pmd, unsigned long address, unsigned long end,
 373                 pgprot_t prot)
 374 {
 375         pte_t *pte = (pte_t *)pmd_page_vaddr(*pmd);
 376
 377         return phys_pte_init(pte, address, end, prot);
 378 }
 379
 380 static unsigned long __meminit
 381 phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end,
 382               unsigned long page_size_mask, pgprot_t prot)
 383 {
 384         unsigned long pages = 0;
 385         unsigned long last_map_addr = end;
 386
 387         int i = pmd_index(address);
 388
 389         for (; i < PTRS_PER_PMD; i++, address += PMD_SIZE) {
 390                 unsigned long pte_phys;
 391                 pmd_t *pmd = pmd_page + pmd_index(address);
 392                 pte_t *pte;
 393                 pgprot_t new_prot = prot;
 394
 395                 if (address >= end) {
 396                         if (!after_bootmem) {
 397                                 for (; i < PTRS_PER_PMD; i++, pmd++)
 398                                         set_pmd(pmd, __pmd(0));
 399                         }
 400                         break;
 401                 }
 402
 403                 if (pmd_val(*pmd)) {
 404                         if (!pmd_large(*pmd)) {
 405                                 spin_lock(&init_mm.page_table_lock);
 406                                 last_map_addr = phys_pte_update(pmd, address,
 407                                                                 end, prot);
 408                                 spin_unlock(&init_mm.page_table_lock);
 409                                 continue;
 410                         }
 411                         /*
 412                          * If we are ok with PG_LEVEL_2M mapping, then we will
 413                          * use the existing mapping,
 414                          *
 415                          * Otherwise, we will split the large page mapping but
 416                          * use the same existing protection bits except for
 417                          * large page, so that we don't violate Intel's TLB
 418                          * Application note (317080) which says, while changing
 419                          * the page sizes, new and old translations should
 420                          * not differ with respect to page frame and
 421                          * attributes.
 422                          */
 423                         if (page_size_mask & (1 << PG_LEVEL_2M)) {
 424                                 pages++;
 425                                 continue;
 426                         }
 427                         new_prot = pte_pgprot(pte_clrhuge(*(pte_t *)pmd));
 428                 }
 429
 430                 if (page_size_mask & (1<<PG_LEVEL_2M)) {
 431                         pages++;
 432                         spin_lock(&init_mm.page_table_lock);
 433                         set_pte((pte_t *)pmd,
 434                                 pfn_pte(address >> PAGE_SHIFT,
 435                                         __pgprot(pgprot_val(prot) | _PAGE_PSE)));
 436                         spin_unlock(&init_mm.page_table_lock);
 437                         last_map_addr = (address & PMD_MASK) + PMD_SIZE;
 438                         continue;
 439                 }
 440
 441                 pte = alloc_low_page(&pte_phys);
 442                 last_map_addr = phys_pte_init(pte, address, end, new_prot);
 443                 unmap_low_page(pte);
 444
 445                 spin_lock(&init_mm.page_table_lock);
 446                 pmd_populate_kernel(&init_mm, pmd, __va(pte_phys));
 447                 spin_unlock(&init_mm.page_table_lock);
 448         }
 449         update_page_count(PG_LEVEL_2M, pages);
 450         return last_map_addr;
 451 }
 452
 453 static unsigned long __meminit
 454 phys_pmd_update(pud_t *pud, unsigned long address, unsigned long end,
 455                 unsigned long page_size_mask, pgprot_t prot)
 456 {
 457         pmd_t *pmd = pmd_offset(pud, 0);
 458         unsigned long last_map_addr;
 459
 460         last_map_addr = phys_pmd_init(pmd, address, end, page_size_mask, prot);
 461         __flush_tlb_all();
 462         return last_map_addr;
 463 }
 464
 465 static unsigned long __meminit
 466 phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end,
 467                          unsigned long page_size_mask)
 468 {
 469         unsigned long pages = 0;
 470         unsigned long last_map_addr = end;
 471         int i = pud_index(addr);
 472
 473         for (; i < PTRS_PER_PUD; i++, addr = (addr & PUD_MASK) + PUD_SIZE) {
 474                 unsigned long pmd_phys;
 475                 pud_t *pud = pud_page + pud_index(addr);
 476                 pmd_t *pmd;
 477                 pgprot_t prot = PAGE_KERNEL;
 478
 479                 if (addr >= end)
 480                         break;
 481
 482                 if (!after_bootmem &&
 483                                 !e820_any_mapped(addr, addr+PUD_SIZE, 0)) {
 484                         set_pud(pud, __pud(0));
 485                         continue;
 486                 }
 487
 488                 if (pud_val(*pud)) {
 489                         if (!pud_large(*pud)) {
 490                                 last_map_addr = phys_pmd_update(pud, addr, end,
 491                                                          page_size_mask, prot);
 492                                 continue;
 493                         }
 494                         /*
 495                          * If we are ok with PG_LEVEL_1G mapping, then we will
 496                          * use the existing mapping.
 497                          *
 498                          * Otherwise, we will split the gbpage mapping but use
 499                          * the same existing protection  bits except for large
 500                          * page, so that we don't violate Intel's TLB
 501                          * Application note (317080) which says, while changing
 502                          * the page sizes, new and old translations should
 503                          * not differ with respect to page frame and
 504                          * attributes.
 505                          */
 506                         if (page_size_mask & (1 << PG_LEVEL_1G)) {
 507                                 pages++;
 508                                 continue;
 509                         }
 510                         prot = pte_pgprot(pte_clrhuge(*(pte_t *)pud));
 511                 }
 512
 513                 if (page_size_mask & (1<<PG_LEVEL_1G)) {
 514                         pages++;
 515                         spin_lock(&init_mm.page_table_lock);
 516                         set_pte((pte_t *)pud,
 517                                 pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE));
 518                         spin_unlock(&init_mm.page_table_lock);
 519                         last_map_addr = (addr & PUD_MASK) + PUD_SIZE;
 520                         continue;
 521                 }
 522
 523                 pmd = alloc_low_page(&pmd_phys);
 524                 last_map_addr = phys_pmd_init(pmd, addr, end, page_size_mask,
 525                                               prot);
 526                 unmap_low_page(pmd);
 527
 528                 spin_lock(&init_mm.page_table_lock);
 529                 pud_populate(&init_mm, pud, __va(pmd_phys));
 530                 spin_unlock(&init_mm.page_table_lock);
 531         }
 532         __flush_tlb_all();
 533
 534         update_page_count(PG_LEVEL_1G, pages);
 535
 536         return last_map_addr;
 537 }
 538
 539 static unsigned long __meminit
 540 phys_pud_update(pgd_t *pgd, unsigned long addr, unsigned long end,
 541                  unsigned long page_size_mask)
 542 {
 543         pud_t *pud;
 544
 545         pud = (pud_t *)pgd_page_vaddr(*pgd);
 546
 547         return phys_pud_init(pud, addr, end, page_size_mask);
 548 }
 549
 550 static void __init find_early_table_space(unsigned long end, int use_pse,
 551                                           int use_gbpages)
 552 {
 553         unsigned long puds, pmds, ptes, tables, start;
 554
 555         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
 556         tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
 557
 558         if (use_gbpages) {
 559                 unsigned long extra;
 560
 561                 extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
 562                 pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
 563         } else
 564                 pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
 565
 566         tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
 567
 568         if (use_pse) {
 569                 unsigned long extra;
 570
 571                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
 572 #ifdef CONFIG_X86_32
 573                 extra += PMD_SIZE;
 574 #endif
 575                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 576         } else
 577                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
 578
 579         tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
 580
 581 #ifdef CONFIG_X86_32
 582         /* for fixmap */
 583         tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
 584 #endif
 585
 586         /*
 587          * RED-PEN putting page tables only on node 0 could
 588          * cause a hotspot and fill up ZONE_DMA. The page tables
 589          * need roughly 0.5KB per GB.
 590          */
 591 #ifdef CONFIG_X86_32
 592         start = 0x7000;
 593         table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
 594                                         tables, PAGE_SIZE);
 595 #else /* CONFIG_X86_64 */
 596         start = 0x8000;
 597         table_start = find_e820_area(start, end, tables, PAGE_SIZE);
 598 #endif
 599         if (table_start == -1UL)
 600                 panic("Cannot find space for the kernel page tables");
 601
 602         table_start >>= PAGE_SHIFT;
 603         table_end = table_start;
 604         table_top = table_start + (tables >> PAGE_SHIFT);
 605
 606         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 607                 end, table_start << PAGE_SHIFT, table_top << PAGE_SHIFT);
 608 }
 609
 610 static void __init init_gbpages(void)
 611 {
 612         if (direct_gbpages && cpu_has_gbpages)
 613                 printk(KERN_INFO "Using GB pages for direct mapping\n");
 614         else
 615                 direct_gbpages = 0;
 616 }
 617
 618 static unsigned long __meminit kernel_physical_mapping_init(unsigned long start,
 619                                                 unsigned long end,
 620                                                 unsigned long page_size_mask)
 621 {
 622
 623         unsigned long next, last_map_addr = end;
 624
 625         start = (unsigned long)__va(start);
 626         end = (unsigned long)__va(end);
 627
 628         for (; start < end; start = next) {
 629                 pgd_t *pgd = pgd_offset_k(start);
 630                 unsigned long pud_phys;
 631                 pud_t *pud;
 632
 633                 next = (start + PGDIR_SIZE) & PGDIR_MASK;
 634                 if (next > end)
 635                         next = end;
 636
 637                 if (pgd_val(*pgd)) {
 638                         last_map_addr = phys_pud_update(pgd, __pa(start),
 639                                                  __pa(end), page_size_mask);
 640                         continue;
 641                 }
 642
 643                 pud = alloc_low_page(&pud_phys);
 644                 last_map_addr = phys_pud_init(pud, __pa(start), __pa(next),
 645                                                  page_size_mask);
 646                 unmap_low_page(pud);
 647
 648                 spin_lock(&init_mm.page_table_lock);
 649                 pgd_populate(&init_mm, pgd, __va(pud_phys));
 650                 spin_unlock(&init_mm.page_table_lock);
 651         }
 652         __flush_tlb_all();
 653
 654         return last_map_addr;
 655 }
 656
 657 struct map_range {
 658         unsigned long start;
 659         unsigned long end;
 660         unsigned page_size_mask;
 661 };
 662
 663 #define NR_RANGE_MR 5
 664
 665 static int save_mr(struct map_range *mr, int nr_range,
 666                    unsigned long start_pfn, unsigned long end_pfn,
 667                    unsigned long page_size_mask)
 668 {
 669         if (start_pfn < end_pfn) {
 670                 if (nr_range >= NR_RANGE_MR)
 671                         panic("run out of range for init_memory_mapping\n");
 672                 mr[nr_range].start = start_pfn<<PAGE_SHIFT;
 673                 mr[nr_range].end   = end_pfn<<PAGE_SHIFT;
 674                 mr[nr_range].page_size_mask = page_size_mask;
 675                 nr_range++;
 676         }
 677
 678         return nr_range;
 679 }
 680
 681 /*
 682  * Setup the direct mapping of the physical memory at PAGE_OFFSET.
 683  * This runs before bootmem is initialized and gets pages directly from
 684  * the physical memory. To access them they are temporarily mapped.
 685  */
 686 unsigned long __init_refok init_memory_mapping(unsigned long start,
 687                                                unsigned long end)
 688 {
 689         unsigned long page_size_mask = 0;
 690         unsigned long start_pfn, end_pfn;
 691         unsigned long pos;
 692         unsigned long ret;
 693
 694         struct map_range mr[NR_RANGE_MR];
 695         int nr_range, i;
 696         int use_pse, use_gbpages;
 697
 698         printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
 699
 700         if (!after_bootmem)
 701                 init_gbpages();
 702
 703 #ifdef CONFIG_DEBUG_PAGEALLOC
 704         /*
 705          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 706          * This will simplify cpa(), which otherwise needs to support splitting
 707          * large pages into small in interrupt context, etc.
 708          */
 709         use_pse = use_gbpages = 0;
 710 #else
 711         use_pse = cpu_has_pse;
 712         use_gbpages = direct_gbpages;
 713 #endif
 714
 715 #ifdef CONFIG_X86_32
 716 #ifdef CONFIG_X86_PAE
 717         set_nx();
 718         if (nx_enabled)
 719                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 720 #endif
 721
 722         /* Enable PSE if available */
 723         if (cpu_has_pse)
 724                 set_in_cr4(X86_CR4_PSE);
 725
 726         /* Enable PGE if available */
 727         if (cpu_has_pge) {
 728                 set_in_cr4(X86_CR4_PGE);
 729                 __supported_pte_mask |= _PAGE_GLOBAL;
 730         }
 731 #endif
 732
 733         if (use_gbpages)
 734                 page_size_mask |= 1 << PG_LEVEL_1G;
 735         if (use_pse)
 736                 page_size_mask |= 1 << PG_LEVEL_2M;
 737
 738         memset(mr, 0, sizeof(mr));
 739         nr_range = 0;
 740
 741         /* head if not big page alignment ? */
 742         start_pfn = start >> PAGE_SHIFT;
 743         pos = start_pfn << PAGE_SHIFT;
 744 #ifdef CONFIG_X86_32
 745         /*
 746          * Don't use a large page for the first 2/4MB of memory
 747          * because there are often fixed size MTRRs in there
 748          * and overlapping MTRRs into large pages can cause
 749          * slowdowns.
 750          */
 751         if (pos == 0)
 752                 end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
 753         else
 754                 end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 755                                  << (PMD_SHIFT - PAGE_SHIFT);
 756 #else /* CONFIG_X86_64 */
 757         end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
 758                         << (PMD_SHIFT - PAGE_SHIFT);
 759 #endif
 760         if (end_pfn > (end >> PAGE_SHIFT))
 761                 end_pfn = end >> PAGE_SHIFT;
 762         if (start_pfn < end_pfn) {
 763                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 764                 pos = end_pfn << PAGE_SHIFT;
 765         }
 766
 767         /* big page (2M) range */
 768         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 769                          << (PMD_SHIFT - PAGE_SHIFT);
 770 #ifdef CONFIG_X86_32
 771         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 772 #else /* CONFIG_X86_64 */
 773         end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 774                          << (PUD_SHIFT - PAGE_SHIFT);
 775         if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
 776                 end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
 777 #endif
 778
 779         if (start_pfn < end_pfn) {
 780                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 781                                 page_size_mask & (1<<PG_LEVEL_2M));
 782                 pos = end_pfn << PAGE_SHIFT;
 783         }
 784
 785 #ifdef CONFIG_X86_64
 786         /* big page (1G) range */
 787         start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
 788                          << (PUD_SHIFT - PAGE_SHIFT);
 789         end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
 790         if (start_pfn < end_pfn) {
 791                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 792                                 page_size_mask &
 793                                  ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
 794                 pos = end_pfn << PAGE_SHIFT;
 795         }
 796
 797         /* tail is not big page (1G) alignment */
 798         start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
 799                          << (PMD_SHIFT - PAGE_SHIFT);
 800         end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 801         if (start_pfn < end_pfn) {
 802                 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
 803                                 page_size_mask & (1<<PG_LEVEL_2M));
 804                 pos = end_pfn << PAGE_SHIFT;
 805         }
 806 #endif
 807
 808         /* tail is not big page (2M) alignment */
 809         start_pfn = pos>>PAGE_SHIFT;
 810         end_pfn = end>>PAGE_SHIFT;
 811         nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
 812
 813         /* try to merge same page size and continuous */
 814         for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
 815                 unsigned long old_start;
 816                 if (mr[i].end != mr[i+1].start ||
 817                     mr[i].page_size_mask != mr[i+1].page_size_mask)
 818                         continue;
 819                 /* move it */
 820                 old_start = mr[i].start;
 821                 memmove(&mr[i], &mr[i+1],
 822                         (nr_range - 1 - i) * sizeof(struct map_range));
 823                 mr[i--].start = old_start;
 824                 nr_range--;
 825         }
 826
 827         for (i = 0; i < nr_range; i++)
 828                 printk(KERN_DEBUG " %010lx - %010lx page %s\n",
 829                                 mr[i].start, mr[i].end,
 830                         (mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
 831                          (mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
 832
 833         /*
 834          * Find space for the kernel direct mapping tables.
 835          *
 836          * Later we should allocate these tables in the local node of the
 837          * memory mapped. Unfortunately this is done currently before the
 838          * nodes are discovered.
 839          */
 840         if (!after_bootmem)
 841                 find_early_table_space(end, use_pse, use_gbpages);
 842
 843 #ifdef CONFIG_X86_32
 844         for (i = 0; i < nr_range; i++)
 845                 kernel_physical_mapping_init(
 846                                 mr[i].start >> PAGE_SHIFT,
 847                                 mr[i].end >> PAGE_SHIFT,
 848                                 mr[i].page_size_mask == (1<<PG_LEVEL_2M));
 849         ret = end;
 850 #else /* CONFIG_X86_64 */
 851         for (i = 0; i < nr_range; i++)
 852                 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
 853                                                    mr[i].page_size_mask);
 854 #endif
 855
 856 #ifdef CONFIG_X86_32
 857         early_ioremap_page_table_range_init();
 858
 859         load_cr3(swapper_pg_dir);
 860 #endif
 861
 862 #ifdef CONFIG_X86_64
 863         if (!after_bootmem)
 864                 mmu_cr4_features = read_cr4();
 865 #endif
 866         __flush_tlb_all();
 867
 868         if (!after_bootmem && table_end > table_start)
 869                 reserve_early(table_start << PAGE_SHIFT,
 870                                  table_end << PAGE_SHIFT, "PGTABLE");
 871
 872         if (!after_bootmem)
 873                 early_memtest(start, end);
 874
 875         return ret >> PAGE_SHIFT;
 876 }
 877
 878 #ifndef CONFIG_NUMA
 879 void __init initmem_init(unsigned long start_pfn, unsigned long end_pfn)
 880 {
 881         unsigned long bootmap_size, bootmap;
 882
 883         bootmap_size = bootmem_bootmap_pages(end_pfn)<<PAGE_SHIFT;
 884         bootmap = find_e820_area(0, end_pfn<<PAGE_SHIFT, bootmap_size,
 885                                  PAGE_SIZE);
 886         if (bootmap == -1L)
 887                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 888         /* don't touch min_low_pfn */
 889         bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
 890                                          0, end_pfn);
 891         e820_register_active_regions(0, start_pfn, end_pfn);
 892         free_bootmem_with_active_regions(0, end_pfn);
 893         early_res_to_bootmem(0, end_pfn<<PAGE_SHIFT);
 894         reserve_bootmem(bootmap, bootmap_size, BOOTMEM_DEFAULT);
 895 }
 896
 897 void __init paging_init(void)
 898 {
 899         unsigned long max_zone_pfns[MAX_NR_ZONES];
 900
 901         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 902         max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
 903         max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
 904         max_zone_pfns[ZONE_NORMAL] = max_pfn;
 905
 906         memory_present(0, 0, max_pfn);
 907         sparse_init();
 908         free_area_init_nodes(max_zone_pfns);
 909 }
 910 #endif
 911
 912 /*
 913  * Memory hotplug specific functions
 914  */
 915 #ifdef CONFIG_MEMORY_HOTPLUG
 916 /*
 917  * Memory is added always to NORMAL zone. This means you will never get
 918  * additional DMA/DMA32 memory.
 919  */
 920 int arch_add_memory(int nid, u64 start, u64 size)
 921 {
 922         struct pglist_data *pgdat = NODE_DATA(nid);
 923         struct zone *zone = pgdat->node_zones + ZONE_NORMAL;
 924         unsigned long last_mapped_pfn, start_pfn = start >> PAGE_SHIFT;
 925         unsigned long nr_pages = size >> PAGE_SHIFT;
 926         int ret;
 927
 928         last_mapped_pfn = init_memory_mapping(start, start + size);
 929         if (last_mapped_pfn > max_pfn_mapped)
 930                 max_pfn_mapped = last_mapped_pfn;
 931
 932         ret = __add_pages(nid, zone, start_pfn, nr_pages);
 933         WARN_ON_ONCE(ret);
 934
 935         return ret;
 936 }
 937 EXPORT_SYMBOL_GPL(arch_add_memory);
 938
 939 #if !defined(CONFIG_ACPI_NUMA) && defined(CONFIG_NUMA)
 940 int memory_add_physaddr_to_nid(u64 start)
 941 {
 942         return 0;
 943 }
 944 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 945 #endif
 946
 947 #endif /* CONFIG_MEMORY_HOTPLUG */
 948
 949 static struct kcore_list kcore_mem, kcore_vmalloc, kcore_kernel,
 950                          kcore_modules, kcore_vsyscall;
 951
 952 void __init mem_init(void)
 953 {
 954         long codesize, reservedpages, datasize, initsize;
 955         unsigned long absent_pages;
 956
 957         pci_iommu_alloc();
 958
 959         /* clear_bss() already clear the empty_zero_page */
 960
 961         reservedpages = 0;
 962
 963         /* this will put all low memory onto the freelists */
 964 #ifdef CONFIG_NUMA
 965         totalram_pages = numa_free_all_bootmem();
 966 #else
 967         totalram_pages = free_all_bootmem();
 968 #endif
 969
 970         absent_pages = absent_pages_in_range(0, max_pfn);
 971         reservedpages = max_pfn - totalram_pages - absent_pages;
 972         after_bootmem = 1;
 973
 974         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 975         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 976         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 977
 978         /* Register memory areas for /proc/kcore */
 979         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 980         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 981                    VMALLOC_END-VMALLOC_START);
 982         kclist_add(&kcore_kernel, &_stext, _end - _stext);
 983         kclist_add(&kcore_modules, (void *)MODULES_VADDR, MODULES_LEN);
 984         kclist_add(&kcore_vsyscall, (void *)VSYSCALL_START,
 985                                  VSYSCALL_END - VSYSCALL_START);
 986
 987         printk(KERN_INFO "Memory: %luk/%luk available (%ldk kernel code, "
 988                          "%ldk absent, %ldk reserved, %ldk data, %ldk init)\n",
 989                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 990                 max_pfn << (PAGE_SHIFT-10),
 991                 codesize >> 10,
 992                 absent_pages << (PAGE_SHIFT-10),
 993                 reservedpages << (PAGE_SHIFT-10),
 994                 datasize >> 10,
 995                 initsize >> 10);
 996 }
 997
 998 #ifdef CONFIG_DEBUG_RODATA
 999 const int rodata_test_data = 0xC3;
1000 EXPORT_SYMBOL_GPL(rodata_test_data);
1001
1002 void mark_rodata_ro(void)
1003 {
1004         unsigned long start = PFN_ALIGN(_stext), end = PFN_ALIGN(__end_rodata);
1005         unsigned long rodata_start =
1006                 ((unsigned long)__start_rodata + PAGE_SIZE - 1) & PAGE_MASK;
1007
1008 #ifdef CONFIG_DYNAMIC_FTRACE
1009         /* Dynamic tracing modifies the kernel text section */
1010         start = rodata_start;
1011 #endif
1012
1013         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1014                (end - start) >> 10);
1015         set_memory_ro(start, (end - start) >> PAGE_SHIFT);
1016
1017         /*
1018          * The rodata section (but not the kernel text!) should also be
1019          * not-executable.
1020          */
1021         set_memory_nx(rodata_start, (end - rodata_start) >> PAGE_SHIFT);
1022
1023         rodata_test();
1024
1025 #ifdef CONFIG_CPA_DEBUG
1026         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, end);
1027         set_memory_rw(start, (end-start) >> PAGE_SHIFT);
1028
1029         printk(KERN_INFO "Testing CPA: again\n");
1030         set_memory_ro(start, (end-start) >> PAGE_SHIFT);
1031 #endif
1032 }
1033
1034 #endif
1035
1036 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1037                                    int flags)
1038 {
1039 #ifdef CONFIG_NUMA
1040         int nid, next_nid;
1041         int ret;
1042 #endif
1043         unsigned long pfn = phys >> PAGE_SHIFT;
1044
1045         if (pfn >= max_pfn) {
1046                 /*
1047                  * This can happen with kdump kernels when accessing
1048                  * firmware tables:
1049                  */
1050                 if (pfn < max_pfn_mapped)
1051                         return -EFAULT;
1052
1053                 printk(KERN_ERR "reserve_bootmem: illegal reserve %lx %lu\n",
1054                                 phys, len);
1055                 return -EFAULT;
1056         }
1057
1058         /* Should check here against the e820 map to avoid double free */
1059 #ifdef CONFIG_NUMA
1060         nid = phys_to_nid(phys);
1061         next_nid = phys_to_nid(phys + len - 1);
1062         if (nid == next_nid)
1063                 ret = reserve_bootmem_node(NODE_DATA(nid), phys, len, flags);
1064         else
1065                 ret = reserve_bootmem(phys, len, flags);
1066
1067         if (ret != 0)
1068                 return ret;
1069
1070 #else
1071         reserve_bootmem(phys, len, BOOTMEM_DEFAULT);
1072 #endif
1073
1074         if (phys+len <= MAX_DMA_PFN*PAGE_SIZE) {
1075                 dma_reserve += len / PAGE_SIZE;
1076                 set_dma_reserve(dma_reserve);
1077         }
1078
1079         return 0;
1080 }
1081
1082 int kern_addr_valid(unsigned long addr)
1083 {
1084         unsigned long above = ((long)addr) >> __VIRTUAL_MASK_SHIFT;
1085         pgd_t *pgd;
1086         pud_t *pud;
1087         pmd_t *pmd;
1088         pte_t *pte;
1089
1090         if (above != 0 && above != -1UL)
1091                 return 0;
1092
1093         pgd = pgd_offset_k(addr);
1094         if (pgd_none(*pgd))
1095                 return 0;
1096
1097         pud = pud_offset(pgd, addr);
1098         if (pud_none(*pud))
1099                 return 0;
1100
1101         pmd = pmd_offset(pud, addr);
1102         if (pmd_none(*pmd))
1103                 return 0;
1104
1105         if (pmd_large(*pmd))
1106                 return pfn_valid(pmd_pfn(*pmd));
1107
1108         pte = pte_offset_kernel(pmd, addr);
1109         if (pte_none(*pte))
1110                 return 0;
1111
1112         return pfn_valid(pte_pfn(*pte));
1113 }
1114
1115 /*
1116  * A pseudo VMA to allow ptrace access for the vsyscall page.  This only
1117  * covers the 64bit vsyscall page now. 32bit has a real VMA now and does
1118  * not need special handling anymore:
1119  */
1120 static struct vm_area_struct gate_vma = {
1121         .vm_start       = VSYSCALL_START,
1122         .vm_end         = VSYSCALL_START + (VSYSCALL_MAPPED_PAGES * PAGE_SIZE),
1123         .vm_page_prot   = PAGE_READONLY_EXEC,
1124         .vm_flags       = VM_READ | VM_EXEC
1125 };
1126
1127 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
1128 {
1129 #ifdef CONFIG_IA32_EMULATION
1130         if (test_tsk_thread_flag(tsk, TIF_IA32))
1131                 return NULL;
1132 #endif
1133         return &gate_vma;
1134 }
1135
1136 int in_gate_area(struct task_struct *task, unsigned long addr)
1137 {
1138         struct vm_area_struct *vma = get_gate_vma(task);
1139
1140         if (!vma)
1141                 return 0;
1142
1143         return (addr >= vma->vm_start) && (addr < vma->vm_end);
1144 }
1145
1146 /*
1147  * Use this when you have no reliable task/vma, typically from interrupt
1148  * context. It is less reliable than using the task's vma and may give
1149  * false positives:
1150  */
1151 int in_gate_area_no_task(unsigned long addr)
1152 {
1153         return (addr >= VSYSCALL_START) && (addr < VSYSCALL_END);
1154 }
1155
1156 const char *arch_vma_name(struct vm_area_struct *vma)
1157 {
1158         if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
1159                 return "[vdso]";
1160         if (vma == &gate_vma)
1161                 return "[vsyscall]";
1162         return NULL;
1163 }
1164
1165 #ifdef CONFIG_SPARSEMEM_VMEMMAP
1166 /*
1167  * Initialise the sparsemem vmemmap using huge-pages at the PMD level.
1168  */
1169 static long __meminitdata addr_start, addr_end;
1170 static void __meminitdata *p_start, *p_end;
1171 static int __meminitdata node_start;
1172
1173 int __meminit
1174 vmemmap_populate(struct page *start_page, unsigned long size, int node)
1175 {
1176         unsigned long addr = (unsigned long)start_page;
1177         unsigned long end = (unsigned long)(start_page + size);
1178         unsigned long next;
1179         pgd_t *pgd;
1180         pud_t *pud;
1181         pmd_t *pmd;
1182
1183         for (; addr < end; addr = next) {
1184                 void *p = NULL;
1185
1186                 pgd = vmemmap_pgd_populate(addr, node);
1187                 if (!pgd)
1188                         return -ENOMEM;
1189
1190                 pud = vmemmap_pud_populate(pgd, addr, node);
1191                 if (!pud)
1192                         return -ENOMEM;
1193
1194                 if (!cpu_has_pse) {
1195                         next = (addr + PAGE_SIZE) & PAGE_MASK;
1196                         pmd = vmemmap_pmd_populate(pud, addr, node);
1197
1198                         if (!pmd)
1199                                 return -ENOMEM;
1200
1201                         p = vmemmap_pte_populate(pmd, addr, node);
1202
1203                         if (!p)
1204                                 return -ENOMEM;
1205
1206                         addr_end = addr + PAGE_SIZE;
1207                         p_end = p + PAGE_SIZE;
1208                 } else {
1209                         next = pmd_addr_end(addr, end);
1210
1211                         pmd = pmd_offset(pud, addr);
1212                         if (pmd_none(*pmd)) {
1213                                 pte_t entry;
1214
1215                                 p = vmemmap_alloc_block(PMD_SIZE, node);
1216                                 if (!p)
1217                                         return -ENOMEM;
1218
1219                                 entry = pfn_pte(__pa(p) >> PAGE_SHIFT,
1220                                                 PAGE_KERNEL_LARGE);
1221                                 set_pmd(pmd, __pmd(pte_val(entry)));
1222
1223                                 /* check to see if we have contiguous blocks */
1224                                 if (p_end != p || node_start != node) {
1225                                         if (p_start)
1226                                                 printk(KERN_DEBUG " [%lx-%lx] PMD -> [%p-%p] on node %d\n",
1227                                                        addr_start, addr_end-1, p_start, p_end-1, node_start);
1228                                         addr_start = addr;
1229                                         node_start = node;
1230                                         p_start = p;
1231                                 }
1232
1233                                 addr_end = addr + PMD_SIZE;
1234                                 p_end = p + PMD_SIZE;
1235                         } else
1236                                 vmemmap_verify((pte_t *)pmd, node, addr, next);
1237                 }
1238
1239         }
1240         return 0;
1241 }
1242
1243 void __meminit vmemmap_populate_print_last(void)
1244 {
1245         if (p_start) {
1246                 printk(KERN_DEBUG " [%lx-%lx] PMD -> [%p-%p] on node %d\n",
1247                         addr_start, addr_end-1, p_start, p_end-1, node_start);
1248                 p_start = NULL;
1249                 p_end = NULL;
1250                 node_start = 0;
1251         }
1252 }
1253 #endif