arch/x86/mm/init_32.c

   1 /*
   2  *
   3  *  Copyright (C) 1995  Linus Torvalds
   4  *
   5  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/signal.h>
  10 #include <linux/sched.h>
  11 #include <linux/kernel.h>
  12 #include <linux/errno.h>
  13 #include <linux/string.h>
  14 #include <linux/types.h>
  15 #include <linux/ptrace.h>
  16 #include <linux/mman.h>
  17 #include <linux/mm.h>
  18 #include <linux/hugetlb.h>
  19 #include <linux/swap.h>
  20 #include <linux/smp.h>
  21 #include <linux/init.h>
  22 #include <linux/highmem.h>
  23 #include <linux/pagemap.h>
  24 #include <linux/pci.h>
  25 #include <linux/pfn.h>
  26 #include <linux/poison.h>
  27 #include <linux/bootmem.h>
  28 #include <linux/slab.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/memory_hotplug.h>
  31 #include <linux/initrd.h>
  32 #include <linux/cpumask.h>
  33
  34 #include <asm/asm.h>
  35 #include <asm/bios_ebda.h>
  36 #include <asm/processor.h>
  37 #include <asm/system.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/pgtable.h>
  40 #include <asm/dma.h>
  41 #include <asm/fixmap.h>
  42 #include <asm/e820.h>
  43 #include <asm/apic.h>
  44 #include <asm/bugs.h>
  45 #include <asm/tlb.h>
  46 #include <asm/tlbflush.h>
  47 #include <asm/pgalloc.h>
  48 #include <asm/sections.h>
  49 #include <asm/paravirt.h>
  50 #include <asm/setup.h>
  51 #include <asm/cacheflush.h>
  52
  53 unsigned long max_low_pfn_mapped;
  54 unsigned long max_pfn_mapped;
  55
  56 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  57 unsigned long highstart_pfn, highend_pfn;
  58
  59 static noinline int do_test_wp_bit(void);
  60
  61
  62 static unsigned long __initdata table_start;
  63 static unsigned long __meminitdata table_end;
  64 static unsigned long __meminitdata table_top;
  65
  66 static int __initdata after_init_bootmem;
  67
  68 static __init void *alloc_low_page(void)
  69 {
  70         unsigned long pfn = table_end++;
  71         void *adr;
  72
  73         if (pfn >= table_top)
  74                 panic("alloc_low_page: ran out of memory");
  75
  76         adr = __va(pfn * PAGE_SIZE);
  77         memset(adr, 0, PAGE_SIZE);
  78         return adr;
  79 }
  80
  81 /*
  82  * Creates a middle page table and puts a pointer to it in the
  83  * given global directory entry. This only returns the gd entry
  84  * in non-PAE compilation mode, since the middle layer is folded.
  85  */
  86 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  87 {
  88         pud_t *pud;
  89         pmd_t *pmd_table;
  90
  91 #ifdef CONFIG_X86_PAE
  92         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  93                 if (after_init_bootmem)
  94                         pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  95                 else
  96                         pmd_table = (pmd_t *)alloc_low_page();
  97                 paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
  98                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  99                 pud = pud_offset(pgd, 0);
 100                 BUG_ON(pmd_table != pmd_offset(pud, 0));
 101
 102                 return pmd_table;
 103         }
 104 #endif
 105         pud = pud_offset(pgd, 0);
 106         pmd_table = pmd_offset(pud, 0);
 107
 108         return pmd_table;
 109 }
 110
 111 /*
 112  * Create a page table and place a pointer to it in a middle page
 113  * directory entry:
 114  */
 115 static pte_t * __init one_page_table_init(pmd_t *pmd)
 116 {
 117         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 118                 pte_t *page_table = NULL;
 119
 120                 if (after_init_bootmem) {
 121 #ifdef CONFIG_DEBUG_PAGEALLOC
 122                         page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 123 #endif
 124                         if (!page_table)
 125                                 page_table =
 126                                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 127                 } else
 128                         page_table = (pte_t *)alloc_low_page();
 129
 130                 paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 131                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 132                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 133         }
 134
 135         return pte_offset_kernel(pmd, 0);
 136 }
 137
 138 static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
 139                                            unsigned long vaddr, pte_t *lastpte)
 140 {
 141 #ifdef CONFIG_HIGHMEM
 142         /*
 143          * Something (early fixmap) may already have put a pte
 144          * page here, which causes the page table allocation
 145          * to become nonlinear. Attempt to fix it, and if it
 146          * is still nonlinear then we have to bug.
 147          */
 148         int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
 149         int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;
 150
 151         if (pmd_idx_kmap_begin != pmd_idx_kmap_end
 152             && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
 153             && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
 154             && ((__pa(pte) >> PAGE_SHIFT) < table_start
 155                 || (__pa(pte) >> PAGE_SHIFT) >= table_end)) {
 156                 pte_t *newpte;
 157                 int i;
 158
 159                 BUG_ON(after_init_bootmem);
 160                 newpte = alloc_low_page();
 161                 for (i = 0; i < PTRS_PER_PTE; i++)
 162                         set_pte(newpte + i, pte[i]);
 163
 164                 paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
 165                 set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
 166                 BUG_ON(newpte != pte_offset_kernel(pmd, 0));
 167                 __flush_tlb_all();
 168
 169                 paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
 170                 pte = newpte;
 171         }
 172         BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
 173                && vaddr > fix_to_virt(FIX_KMAP_END)
 174                && lastpte && lastpte + PTRS_PER_PTE != pte);
 175 #endif
 176         return pte;
 177 }
 178
 179 /*
 180  * This function initializes a certain range of kernel virtual memory
 181  * with new bootmem page tables, everywhere page tables are missing in
 182  * the given range.
 183  *
 184  * NOTE: The pagetables are allocated contiguous on the physical space
 185  * so we can cache the place of the first one and move around without
 186  * checking the pgd every time.
 187  */
 188 static void __init
 189 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 190 {
 191         int pgd_idx, pmd_idx;
 192         unsigned long vaddr;
 193         pgd_t *pgd;
 194         pmd_t *pmd;
 195         pte_t *pte = NULL;
 196
 197         vaddr = start;
 198         pgd_idx = pgd_index(vaddr);
 199         pmd_idx = pmd_index(vaddr);
 200         pgd = pgd_base + pgd_idx;
 201
 202         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 203                 pmd = one_md_table_init(pgd);
 204                 pmd = pmd + pmd_index(vaddr);
 205                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 206                                                         pmd++, pmd_idx++) {
 207                         pte = page_table_kmap_check(one_page_table_init(pmd),
 208                                                     pmd, vaddr, pte);
 209
 210                         vaddr += PMD_SIZE;
 211                 }
 212                 pmd_idx = 0;
 213         }
 214 }
 215
 216 static inline int is_kernel_text(unsigned long addr)
 217 {
 218         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 219                 return 1;
 220         return 0;
 221 }
 222
 223 /*
 224  * This maps the physical memory to kernel virtual address space, a total
 225  * of max_low_pfn pages, by creating page tables starting from address
 226  * PAGE_OFFSET:
 227  */
 228 static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
 229                                                 unsigned long start_pfn,
 230                                                 unsigned long end_pfn,
 231                                                 int use_pse)
 232 {
 233         int pgd_idx, pmd_idx, pte_ofs;
 234         unsigned long pfn;
 235         pgd_t *pgd;
 236         pmd_t *pmd;
 237         pte_t *pte;
 238         unsigned pages_2m, pages_4k;
 239         int mapping_iter;
 240
 241         /*
 242          * First iteration will setup identity mapping using large/small pages
 243          * based on use_pse, with other attributes same as set by
 244          * the early code in head_32.S
 245          *
 246          * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
 247          * as desired for the kernel identity mapping.
 248          *
 249          * This two pass mechanism conforms to the TLB app note which says:
 250          *
 251          *     "Software should not write to a paging-structure entry in a way
 252          *      that would change, for any linear address, both the page size
 253          *      and either the page frame or attributes."
 254          */
 255         mapping_iter = 1;
 256
 257         if (!cpu_has_pse)
 258                 use_pse = 0;
 259
 260 repeat:
 261         pages_2m = pages_4k = 0;
 262         pfn = start_pfn;
 263         pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 264         pgd = pgd_base + pgd_idx;
 265         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 266                 pmd = one_md_table_init(pgd);
 267
 268                 if (pfn >= end_pfn)
 269                         continue;
 270 #ifdef CONFIG_X86_PAE
 271                 pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 272                 pmd += pmd_idx;
 273 #else
 274                 pmd_idx = 0;
 275 #endif
 276                 for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 277                      pmd++, pmd_idx++) {
 278                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 279
 280                         /*
 281                          * Map with big pages if possible, otherwise
 282                          * create normal page tables:
 283                          */
 284                         if (use_pse) {
 285                                 unsigned int addr2;
 286                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 287                                 /*
 288                                  * first pass will use the same initial
 289                                  * identity mapping attribute + _PAGE_PSE.
 290                                  */
 291                                 pgprot_t init_prot =
 292                                         __pgprot(PTE_IDENT_ATTR |
 293                                                  _PAGE_PSE);
 294
 295                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 296                                         PAGE_OFFSET + PAGE_SIZE-1;
 297
 298                                 if (is_kernel_text(addr) ||
 299                                     is_kernel_text(addr2))
 300                                         prot = PAGE_KERNEL_LARGE_EXEC;
 301
 302                                 pages_2m++;
 303                                 if (mapping_iter == 1)
 304                                         set_pmd(pmd, pfn_pmd(pfn, init_prot));
 305                                 else
 306                                         set_pmd(pmd, pfn_pmd(pfn, prot));
 307
 308                                 pfn += PTRS_PER_PTE;
 309                                 continue;
 310                         }
 311                         pte = one_page_table_init(pmd);
 312
 313                         pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 314                         pte += pte_ofs;
 315                         for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 316                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 317                                 pgprot_t prot = PAGE_KERNEL;
 318                                 /*
 319                                  * first pass will use the same initial
 320                                  * identity mapping attribute.
 321                                  */
 322                                 pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 323
 324                                 if (is_kernel_text(addr))
 325                                         prot = PAGE_KERNEL_EXEC;
 326
 327                                 pages_4k++;
 328                                 if (mapping_iter == 1)
 329                                         set_pte(pte, pfn_pte(pfn, init_prot));
 330                                 else
 331                                         set_pte(pte, pfn_pte(pfn, prot));
 332                         }
 333                 }
 334         }
 335         if (mapping_iter == 1) {
 336                 /*
 337                  * update direct mapping page count only in the first
 338                  * iteration.
 339                  */
 340                 update_page_count(PG_LEVEL_2M, pages_2m);
 341                 update_page_count(PG_LEVEL_4K, pages_4k);
 342
 343                 /*
 344                  * local global flush tlb, which will flush the previous
 345                  * mappings present in both small and large page TLB's.
 346                  */
 347                 __flush_tlb_all();
 348
 349                 /*
 350                  * Second iteration will set the actual desired PTE attributes.
 351                  */
 352                 mapping_iter = 2;
 353                 goto repeat;
 354         }
 355 }
 356
 357 /*
 358  * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 359  * is valid. The argument is a physical page number.
 360  *
 361  *
 362  * On x86, access has to be given to the first megabyte of ram because that area
 363  * contains bios code and data regions used by X and dosemu and similar apps.
 364  * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 365  * mmio resources as well as potential bios/acpi data regions.
 366  */
 367 int devmem_is_allowed(unsigned long pagenr)
 368 {
 369         if (pagenr <= 256)
 370                 return 1;
 371         if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
 372                 return 0;
 373         if (!page_is_ram(pagenr))
 374                 return 1;
 375         return 0;
 376 }
 377
 378 pte_t *kmap_pte;
 379 pgprot_t kmap_prot;
 380
 381 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 382 {
 383         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 384                         vaddr), vaddr), vaddr);
 385 }
 386
 387 static void __init kmap_init(void)
 388 {
 389         unsigned long kmap_vstart;
 390
 391         /*
 392          * Cache the first kmap pte:
 393          */
 394         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 395         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 396
 397         kmap_prot = PAGE_KERNEL;
 398 }
 399
 400 #ifdef CONFIG_HIGHMEM
 401 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 402 {
 403         unsigned long vaddr;
 404         pgd_t *pgd;
 405         pud_t *pud;
 406         pmd_t *pmd;
 407         pte_t *pte;
 408
 409         vaddr = PKMAP_BASE;
 410         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 411
 412         pgd = swapper_pg_dir + pgd_index(vaddr);
 413         pud = pud_offset(pgd, vaddr);
 414         pmd = pmd_offset(pud, vaddr);
 415         pte = pte_offset_kernel(pmd, vaddr);
 416         pkmap_page_table = pte;
 417 }
 418
 419 static void __init add_one_highpage_init(struct page *page, int pfn)
 420 {
 421         ClearPageReserved(page);
 422         init_page_count(page);
 423         __free_page(page);
 424         totalhigh_pages++;
 425 }
 426
 427 struct add_highpages_data {
 428         unsigned long start_pfn;
 429         unsigned long end_pfn;
 430 };
 431
 432 static int __init add_highpages_work_fn(unsigned long start_pfn,
 433                                          unsigned long end_pfn, void *datax)
 434 {
 435         int node_pfn;
 436         struct page *page;
 437         unsigned long final_start_pfn, final_end_pfn;
 438         struct add_highpages_data *data;
 439
 440         data = (struct add_highpages_data *)datax;
 441
 442         final_start_pfn = max(start_pfn, data->start_pfn);
 443         final_end_pfn = min(end_pfn, data->end_pfn);
 444         if (final_start_pfn >= final_end_pfn)
 445                 return 0;
 446
 447         for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 448              node_pfn++) {
 449                 if (!pfn_valid(node_pfn))
 450                         continue;
 451                 page = pfn_to_page(node_pfn);
 452                 add_one_highpage_init(page, node_pfn);
 453         }
 454
 455         return 0;
 456
 457 }
 458
 459 void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 460                                               unsigned long end_pfn)
 461 {
 462         struct add_highpages_data data;
 463
 464         data.start_pfn = start_pfn;
 465         data.end_pfn = end_pfn;
 466
 467         work_with_active_regions(nid, add_highpages_work_fn, &data);
 468 }
 469
 470 #else
 471 static inline void permanent_kmaps_init(pgd_t *pgd_base)
 472 {
 473 }
 474 #endif /* CONFIG_HIGHMEM */
 475
 476 void __init native_pagetable_setup_start(pgd_t *base)
 477 {
 478         unsigned long pfn, va;
 479         pgd_t *pgd;
 480         pud_t *pud;
 481         pmd_t *pmd;
 482         pte_t *pte;
 483
 484         /*
 485          * Remove any mappings which extend past the end of physical
 486          * memory from the boot time page table:
 487          */
 488         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 489                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 490                 pgd = base + pgd_index(va);
 491                 if (!pgd_present(*pgd))
 492                         break;
 493
 494                 pud = pud_offset(pgd, va);
 495                 pmd = pmd_offset(pud, va);
 496                 if (!pmd_present(*pmd))
 497                         break;
 498
 499                 pte = pte_offset_kernel(pmd, va);
 500                 if (!pte_present(*pte))
 501                         break;
 502
 503                 pte_clear(NULL, va, pte);
 504         }
 505         paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 506 }
 507
 508 void __init native_pagetable_setup_done(pgd_t *base)
 509 {
 510 }
 511
 512 /*
 513  * Build a proper pagetable for the kernel mappings.  Up until this
 514  * point, we've been running on some set of pagetables constructed by
 515  * the boot process.
 516  *
 517  * If we're booting on native hardware, this will be a pagetable
 518  * constructed in arch/x86/kernel/head_32.S.  The root of the
 519  * pagetable will be swapper_pg_dir.
 520  *
 521  * If we're booting paravirtualized under a hypervisor, then there are
 522  * more options: we may already be running PAE, and the pagetable may
 523  * or may not be based in swapper_pg_dir.  In any case,
 524  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 525  * appropriately for the rest of the initialization to work.
 526  *
 527  * In general, pagetable_init() assumes that the pagetable may already
 528  * be partially populated, and so it avoids stomping on any existing
 529  * mappings.
 530  */
 531 static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
 532 {
 533         unsigned long vaddr, end;
 534
 535         /*
 536          * Fixed mappings, only the page table structure has to be
 537          * created - mappings will be set by set_fixmap():
 538          */
 539         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 540         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 541         page_table_range_init(vaddr, end, pgd_base);
 542         early_ioremap_reset();
 543 }
 544
 545 static void __init pagetable_init(void)
 546 {
 547         pgd_t *pgd_base = swapper_pg_dir;
 548
 549         permanent_kmaps_init(pgd_base);
 550 }
 551
 552 #ifdef CONFIG_ACPI_SLEEP
 553 /*
 554  * ACPI suspend needs this for resume, because things like the intel-agp
 555  * driver might have split up a kernel 4MB mapping.
 556  */
 557 char swsusp_pg_dir[PAGE_SIZE]
 558         __attribute__ ((aligned(PAGE_SIZE)));
 559
 560 static inline void save_pg_dir(void)
 561 {
 562         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 563 }
 564 #else /* !CONFIG_ACPI_SLEEP */
 565 static inline void save_pg_dir(void)
 566 {
 567 }
 568 #endif /* !CONFIG_ACPI_SLEEP */
 569
 570 void zap_low_mappings(void)
 571 {
 572         int i;
 573
 574         /*
 575          * Zap initial low-memory mappings.
 576          *
 577          * Note that "pgd_clear()" doesn't do it for
 578          * us, because pgd_clear() is a no-op on i386.
 579          */
 580         for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 581 #ifdef CONFIG_X86_PAE
 582                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 583 #else
 584                 set_pgd(swapper_pg_dir+i, __pgd(0));
 585 #endif
 586         }
 587         flush_tlb_all();
 588 }
 589
 590 int nx_enabled;
 591
 592 pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 593 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 594
 595 #ifdef CONFIG_X86_PAE
 596
 597 static int disable_nx __initdata;
 598
 599 /*
 600  * noexec = on|off
 601  *
 602  * Control non executable mappings.
 603  *
 604  * on      Enable
 605  * off     Disable
 606  */
 607 static int __init noexec_setup(char *str)
 608 {
 609         if (!str || !strcmp(str, "on")) {
 610                 if (cpu_has_nx) {
 611                         __supported_pte_mask |= _PAGE_NX;
 612                         disable_nx = 0;
 613                 }
 614         } else {
 615                 if (!strcmp(str, "off")) {
 616                         disable_nx = 1;
 617                         __supported_pte_mask &= ~_PAGE_NX;
 618                 } else {
 619                         return -EINVAL;
 620                 }
 621         }
 622
 623         return 0;
 624 }
 625 early_param("noexec", noexec_setup);
 626
 627 static void __init set_nx(void)
 628 {
 629         unsigned int v[4], l, h;
 630
 631         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 632                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 633
 634                 if ((v[3] & (1 << 20)) && !disable_nx) {
 635                         rdmsr(MSR_EFER, l, h);
 636                         l |= EFER_NX;
 637                         wrmsr(MSR_EFER, l, h);
 638                         nx_enabled = 1;
 639                         __supported_pte_mask |= _PAGE_NX;
 640                 }
 641         }
 642 }
 643 #endif
 644
 645 /* user-defined highmem size */
 646 static unsigned int highmem_pages = -1;
 647
 648 /*
 649  * highmem=size forces highmem to be exactly 'size' bytes.
 650  * This works even on boxes that have no highmem otherwise.
 651  * This also works to reduce highmem size on bigger boxes.
 652  */
 653 static int __init parse_highmem(char *arg)
 654 {
 655         if (!arg)
 656                 return -EINVAL;
 657
 658         highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 659         return 0;
 660 }
 661 early_param("highmem", parse_highmem);
 662
 663 #define MSG_HIGHMEM_TOO_BIG \
 664         "highmem size (%luMB) is bigger than pages available (%luMB)!\n"
 665
 666 #define MSG_LOWMEM_TOO_SMALL \
 667         "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
 668 /*
 669  * All of RAM fits into lowmem - but if user wants highmem
 670  * artificially via the highmem=x boot parameter then create
 671  * it:
 672  */
 673 void __init lowmem_pfn_init(void)
 674 {
 675         /* max_low_pfn is 0, we already have early_res support */
 676         max_low_pfn = max_pfn;
 677
 678         if (highmem_pages == -1)
 679                 highmem_pages = 0;
 680 #ifdef CONFIG_HIGHMEM
 681         if (highmem_pages >= max_pfn) {
 682                 printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
 683                         pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
 684                 highmem_pages = 0;
 685         }
 686         if (highmem_pages) {
 687                 if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
 688                         printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
 689                                 pages_to_mb(highmem_pages));
 690                         highmem_pages = 0;
 691                 }
 692                 max_low_pfn -= highmem_pages;
 693         }
 694 #else
 695         if (highmem_pages)
 696                 printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
 697 #endif
 698 }
 699
 700 #define MSG_HIGHMEM_TOO_SMALL \
 701         "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"
 702
 703 #define MSG_HIGHMEM_TRIMMED \
 704         "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
 705 /*
 706  * We have more RAM than fits into lowmem - we try to put it into
 707  * highmem, also taking the highmem=x boot parameter into account:
 708  */
 709 void __init highmem_pfn_init(void)
 710 {
 711         max_low_pfn = MAXMEM_PFN;
 712
 713         if (highmem_pages == -1)
 714                 highmem_pages = max_pfn - MAXMEM_PFN;
 715
 716         if (highmem_pages + MAXMEM_PFN < max_pfn)
 717                 max_pfn = MAXMEM_PFN + highmem_pages;
 718
 719         if (highmem_pages + MAXMEM_PFN > max_pfn) {
 720                 printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
 721                         pages_to_mb(max_pfn - MAXMEM_PFN),
 722                         pages_to_mb(highmem_pages));
 723                 highmem_pages = 0;
 724         }
 725 #ifndef CONFIG_HIGHMEM
 726         /* Maximum memory usable is what is directly addressable */
 727         printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
 728         if (max_pfn > MAX_NONPAE_PFN)
 729                 printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
 730         else
 731                 printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 732         max_pfn = MAXMEM_PFN;
 733 #else /* !CONFIG_HIGHMEM */
 734 #ifndef CONFIG_HIGHMEM64G
 735         if (max_pfn > MAX_NONPAE_PFN) {
 736                 max_pfn = MAX_NONPAE_PFN;
 737                 printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
 738         }
 739 #endif /* !CONFIG_HIGHMEM64G */
 740 #endif /* !CONFIG_HIGHMEM */
 741 }
 742
 743 /*
 744  * Determine low and high memory ranges:
 745  */
 746 void __init find_low_pfn_range(void)
 747 {
 748         /* it could update max_pfn */
 749
 750         if (max_pfn <= MAXMEM_PFN)
 751                 lowmem_pfn_init();
 752         else
 753                 highmem_pfn_init();
 754 }
 755
 756 #ifndef CONFIG_NEED_MULTIPLE_NODES
 757 void __init initmem_init(unsigned long start_pfn,
 758                                   unsigned long end_pfn)
 759 {
 760 #ifdef CONFIG_HIGHMEM
 761         highstart_pfn = highend_pfn = max_pfn;
 762         if (max_pfn > max_low_pfn)
 763                 highstart_pfn = max_low_pfn;
 764         memory_present(0, 0, highend_pfn);
 765         e820_register_active_regions(0, 0, highend_pfn);
 766         printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 767                 pages_to_mb(highend_pfn - highstart_pfn));
 768         num_physpages = highend_pfn;
 769         high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 770 #else
 771         memory_present(0, 0, max_low_pfn);
 772         e820_register_active_regions(0, 0, max_low_pfn);
 773         num_physpages = max_low_pfn;
 774         high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 775 #endif
 776 #ifdef CONFIG_FLATMEM
 777         max_mapnr = num_physpages;
 778 #endif
 779         printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 780                         pages_to_mb(max_low_pfn));
 781
 782         setup_bootmem_allocator();
 783 }
 784 #endif /* !CONFIG_NEED_MULTIPLE_NODES */
 785
 786 static void __init zone_sizes_init(void)
 787 {
 788         unsigned long max_zone_pfns[MAX_NR_ZONES];
 789         memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 790         max_zone_pfns[ZONE_DMA] =
 791                 virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 792         max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 793 #ifdef CONFIG_HIGHMEM
 794         max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 795 #endif
 796
 797         free_area_init_nodes(max_zone_pfns);
 798 }
 799
 800 void __init setup_bootmem_allocator(void)
 801 {
 802         int i;
 803         unsigned long bootmap_size, bootmap;
 804         /*
 805          * Initialize the boot-time allocator (with low memory only):
 806          */
 807         bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 808         bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
 809                                  max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 810                                  PAGE_SIZE);
 811         if (bootmap == -1L)
 812                 panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 813         reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 814
 815         /* don't touch min_low_pfn */
 816         bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
 817                                          min_low_pfn, max_low_pfn);
 818         printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 819                  max_pfn_mapped<<PAGE_SHIFT);
 820         printk(KERN_INFO "  low ram: %08lx - %08lx\n",
 821                  min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
 822         printk(KERN_INFO "  bootmap %08lx - %08lx\n",
 823                  bootmap, bootmap + bootmap_size);
 824         for_each_online_node(i)
 825                 free_bootmem_with_active_regions(i, max_low_pfn);
 826         early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
 827
 828         after_init_bootmem = 1;
 829 }
 830
 831 static void __init find_early_table_space(unsigned long end, int use_pse)
 832 {
 833         unsigned long puds, pmds, ptes, tables, start;
 834
 835         puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
 836         tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
 837
 838         pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
 839         tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
 840
 841         if (use_pse) {
 842                 unsigned long extra;
 843
 844                 extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
 845                 extra += PMD_SIZE;
 846                 ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 847         } else
 848                 ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
 849
 850         tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
 851
 852         /* for fixmap */
 853         tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
 854
 855         /*
 856          * RED-PEN putting page tables only on node 0 could
 857          * cause a hotspot and fill up ZONE_DMA. The page tables
 858          * need roughly 0.5KB per GB.
 859          */
 860         start = 0x7000;
 861         table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
 862                                         tables, PAGE_SIZE);
 863         if (table_start == -1UL)
 864                 panic("Cannot find space for the kernel page tables");
 865
 866         table_start >>= PAGE_SHIFT;
 867         table_end = table_start;
 868         table_top = table_start + (tables>>PAGE_SHIFT);
 869
 870         printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 871                 end, table_start << PAGE_SHIFT,
 872                 (table_start << PAGE_SHIFT) + tables);
 873 }
 874
 875 unsigned long __init_refok init_memory_mapping(unsigned long start,
 876                                                 unsigned long end)
 877 {
 878         pgd_t *pgd_base = swapper_pg_dir;
 879         unsigned long start_pfn, end_pfn;
 880         unsigned long big_page_start;
 881 #ifdef CONFIG_DEBUG_PAGEALLOC
 882         /*
 883          * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 884          * This will simplify cpa(), which otherwise needs to support splitting
 885          * large pages into small in interrupt context, etc.
 886          */
 887         int use_pse = 0;
 888 #else
 889         int use_pse = cpu_has_pse;
 890 #endif
 891
 892         /*
 893          * Find space for the kernel direct mapping tables.
 894          */
 895         if (!after_init_bootmem)
 896                 find_early_table_space(end, use_pse);
 897
 898 #ifdef CONFIG_X86_PAE
 899         set_nx();
 900         if (nx_enabled)
 901                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 902 #endif
 903
 904         /* Enable PSE if available */
 905         if (cpu_has_pse)
 906                 set_in_cr4(X86_CR4_PSE);
 907
 908         /* Enable PGE if available */
 909         if (cpu_has_pge) {
 910                 set_in_cr4(X86_CR4_PGE);
 911                 __supported_pte_mask |= _PAGE_GLOBAL;
 912         }
 913
 914         /*
 915          * Don't use a large page for the first 2/4MB of memory
 916          * because there are often fixed size MTRRs in there
 917          * and overlapping MTRRs into large pages can cause
 918          * slowdowns.
 919          */
 920         big_page_start = PMD_SIZE;
 921
 922         if (start < big_page_start) {
 923                 start_pfn = start >> PAGE_SHIFT;
 924                 end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
 925         } else {
 926                 /* head is not big page alignment ? */
 927                 start_pfn = start >> PAGE_SHIFT;
 928                 end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 929                                  << (PMD_SHIFT - PAGE_SHIFT);
 930         }
 931         if (start_pfn < end_pfn)
 932                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
 933
 934         /* big page range */
 935         start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 936                          << (PMD_SHIFT - PAGE_SHIFT);
 937         if (start_pfn < (big_page_start >> PAGE_SHIFT))
 938                 start_pfn =  big_page_start >> PAGE_SHIFT;
 939         end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 940         if (start_pfn < end_pfn)
 941                 kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
 942                                              use_pse);
 943
 944         /* tail is not big page alignment ? */
 945         start_pfn = end_pfn;
 946         if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
 947                 end_pfn = end >> PAGE_SHIFT;
 948                 if (start_pfn < end_pfn)
 949                         kernel_physical_mapping_init(pgd_base, start_pfn,
 950                                                          end_pfn, 0);
 951         }
 952
 953         early_ioremap_page_table_range_init(pgd_base);
 954
 955         load_cr3(swapper_pg_dir);
 956
 957         __flush_tlb_all();
 958
 959         if (!after_init_bootmem)
 960                 reserve_early(table_start << PAGE_SHIFT,
 961                                  table_end << PAGE_SHIFT, "PGTABLE");
 962
 963         if (!after_init_bootmem)
 964                 early_memtest(start, end);
 965
 966         return end >> PAGE_SHIFT;
 967 }
 968
 969
 970 /*
 971  * paging_init() sets up the page tables - note that the first 8MB are
 972  * already mapped by head.S.
 973  *
 974  * This routines also unmaps the page at virtual kernel address 0, so
 975  * that we can trap those pesky NULL-reference errors in the kernel.
 976  */
 977 void __init paging_init(void)
 978 {
 979         pagetable_init();
 980
 981         __flush_tlb_all();
 982
 983         kmap_init();
 984
 985         /*
 986          * NOTE: at this point the bootmem allocator is fully available.
 987          */
 988         sparse_init();
 989         zone_sizes_init();
 990 }
 991
 992 /*
 993  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 994  * and also on some strange 486's. All 586+'s are OK. This used to involve
 995  * black magic jumps to work around some nasty CPU bugs, but fortunately the
 996  * switch to using exceptions got rid of all that.
 997  */
 998 static void __init test_wp_bit(void)
 999 {
1000         printk(KERN_INFO
1001   "Checking if this processor honours the WP bit even in supervisor mode...");
1002
1003         /* Any page-aligned address will do, the test is non-destructive */
1004         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
1005         boot_cpu_data.wp_works_ok = do_test_wp_bit();
1006         clear_fixmap(FIX_WP_TEST);
1007
1008         if (!boot_cpu_data.wp_works_ok) {
1009                 printk(KERN_CONT "No.\n");
1010 #ifdef CONFIG_X86_WP_WORKS_OK
1011                 panic(
1012   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
1013 #endif
1014         } else {
1015                 printk(KERN_CONT "Ok.\n");
1016         }
1017 }
1018
1019 static struct kcore_list kcore_mem, kcore_vmalloc;
1020
1021 void __init mem_init(void)
1022 {
1023         int codesize, reservedpages, datasize, initsize;
1024         int tmp;
1025
1026         pci_iommu_alloc();
1027
1028 #ifdef CONFIG_FLATMEM
1029         BUG_ON(!mem_map);
1030 #endif
1031         /* this will put all low memory onto the freelists */
1032         totalram_pages += free_all_bootmem();
1033
1034         reservedpages = 0;
1035         for (tmp = 0; tmp < max_low_pfn; tmp++)
1036                 /*
1037                  * Only count reserved RAM pages:
1038                  */
1039                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
1040                         reservedpages++;
1041
1042         set_highmem_pages_init();
1043
1044         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
1045         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
1046         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
1047
1048         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
1049         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
1050                    VMALLOC_END-VMALLOC_START);
1051
1052         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
1053                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
1054                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
1055                 num_physpages << (PAGE_SHIFT-10),
1056                 codesize >> 10,
1057                 reservedpages << (PAGE_SHIFT-10),
1058                 datasize >> 10,
1059                 initsize >> 10,
1060                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
1061                );
1062
1063         printk(KERN_INFO "virtual kernel memory layout:\n"
1064                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1065 #ifdef CONFIG_HIGHMEM
1066                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1067 #endif
1068                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1069                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1070                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1071                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1072                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
1073                 FIXADDR_START, FIXADDR_TOP,
1074                 (FIXADDR_TOP - FIXADDR_START) >> 10,
1075
1076 #ifdef CONFIG_HIGHMEM
1077                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
1078                 (LAST_PKMAP*PAGE_SIZE) >> 10,
1079 #endif
1080
1081                 VMALLOC_START, VMALLOC_END,
1082                 (VMALLOC_END - VMALLOC_START) >> 20,
1083
1084                 (unsigned long)__va(0), (unsigned long)high_memory,
1085                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
1086
1087                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
1088                 ((unsigned long)&__init_end -
1089                  (unsigned long)&__init_begin) >> 10,
1090
1091                 (unsigned long)&_etext, (unsigned long)&_edata,
1092                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
1093
1094                 (unsigned long)&_text, (unsigned long)&_etext,
1095                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
1096
1097         /*
1098          * Check boundaries twice: Some fundamental inconsistencies can
1099          * be detected at build time already.
1100          */
1101 #define __FIXADDR_TOP (-PAGE_SIZE)
1102 #ifdef CONFIG_HIGHMEM
1103         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
1104         BUILD_BUG_ON(VMALLOC_END                        > PKMAP_BASE);
1105 #endif
1106 #define high_memory (-128UL << 20)
1107         BUILD_BUG_ON(VMALLOC_START                      >= VMALLOC_END);
1108 #undef high_memory
1109 #undef __FIXADDR_TOP
1110
1111 #ifdef CONFIG_HIGHMEM
1112         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
1113         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
1114 #endif
1115         BUG_ON(VMALLOC_START                            >= VMALLOC_END);
1116         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
1117
1118         if (boot_cpu_data.wp_works_ok < 0)
1119                 test_wp_bit();
1120
1121         save_pg_dir();
1122         zap_low_mappings();
1123 }
1124
1125 #ifdef CONFIG_MEMORY_HOTPLUG
1126 int arch_add_memory(int nid, u64 start, u64 size)
1127 {
1128         struct pglist_data *pgdata = NODE_DATA(nid);
1129         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1130         unsigned long start_pfn = start >> PAGE_SHIFT;
1131         unsigned long nr_pages = size >> PAGE_SHIFT;
1132
1133         return __add_pages(nid, zone, start_pfn, nr_pages);
1134 }
1135 #endif
1136
1137 /*
1138  * This function cannot be __init, since exceptions don't work in that
1139  * section.  Put this after the callers, so that it cannot be inlined.
1140  */
1141 static noinline int do_test_wp_bit(void)
1142 {
1143         char tmp_reg;
1144         int flag;
1145
1146         __asm__ __volatile__(
1147                 "       movb %0, %1     \n"
1148                 "1:     movb %1, %0     \n"
1149                 "       xorl %2, %2     \n"
1150                 "2:                     \n"
1151                 _ASM_EXTABLE(1b,2b)
1152                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1153                  "=q" (tmp_reg),
1154                  "=r" (flag)
1155                 :"2" (1)
1156                 :"memory");
1157
1158         return flag;
1159 }
1160
1161 #ifdef CONFIG_DEBUG_RODATA
1162 const int rodata_test_data = 0xC3;
1163 EXPORT_SYMBOL_GPL(rodata_test_data);
1164
1165 void mark_rodata_ro(void)
1166 {
1167         unsigned long start = PFN_ALIGN(_text);
1168         unsigned long size = PFN_ALIGN(_etext) - start;
1169
1170 #ifndef CONFIG_DYNAMIC_FTRACE
1171         /* Dynamic tracing modifies the kernel text section */
1172         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1173         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1174                 size >> 10);
1175
1176 #ifdef CONFIG_CPA_DEBUG
1177         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1178                 start, start+size);
1179         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1180
1181         printk(KERN_INFO "Testing CPA: write protecting again\n");
1182         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1183 #endif
1184 #endif /* CONFIG_DYNAMIC_FTRACE */
1185
1186         start += size;
1187         size = (unsigned long)__end_rodata - start;
1188         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1189         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1190                 size >> 10);
1191         rodata_test();
1192
1193 #ifdef CONFIG_CPA_DEBUG
1194         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1195         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1196
1197         printk(KERN_INFO "Testing CPA: write protecting again\n");
1198         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1199 #endif
1200 }
1201 #endif
1202
1203 #ifdef CONFIG_BLK_DEV_INITRD
1204 void free_initrd_mem(unsigned long start, unsigned long end)
1205 {
1206         free_init_pages("initrd memory", start, end);
1207 }
1208 #endif
1209
1210 int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1211                                    int flags)
1212 {
1213         return reserve_bootmem(phys, len, flags);
1214 }