arch/x86/mm/init_32.c

   1 /*
   2  *  linux/arch/i386/mm/init.c
   3  *
   4  *  Copyright (C) 1995  Linus Torvalds
   5  *
   6  *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/signal.h>
  11 #include <linux/sched.h>
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/string.h>
  15 #include <linux/types.h>
  16 #include <linux/ptrace.h>
  17 #include <linux/mman.h>
  18 #include <linux/mm.h>
  19 #include <linux/hugetlb.h>
  20 #include <linux/swap.h>
  21 #include <linux/smp.h>
  22 #include <linux/init.h>
  23 #include <linux/highmem.h>
  24 #include <linux/pagemap.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/efi.h>
  31 #include <linux/memory_hotplug.h>
  32 #include <linux/initrd.h>
  33 #include <linux/cpumask.h>
  34
  35 #include <asm/processor.h>
  36 #include <asm/system.h>
  37 #include <asm/uaccess.h>
  38 #include <asm/pgtable.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/tlbflush.h>
  45 #include <asm/sections.h>
  46 #include <asm/paravirt.h>
  47
  48 unsigned int __VMALLOC_RESERVE = 128 << 20;
  49
  50 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  51 unsigned long highstart_pfn, highend_pfn;
  52
  53 static int noinline do_test_wp_bit(void);
  54
  55 /*
  56  * Creates a middle page table and puts a pointer to it in the
  57  * given global directory entry. This only returns the gd entry
  58  * in non-PAE compilation mode, since the middle layer is folded.
  59  */
  60 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  61 {
  62         pud_t *pud;
  63         pmd_t *pmd_table;
  64
  65 #ifdef CONFIG_X86_PAE
  66         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  67                 pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  68
  69                 paravirt_alloc_pd(__pa(pmd_table) >> PAGE_SHIFT);
  70                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  71                 pud = pud_offset(pgd, 0);
  72                 if (pmd_table != pmd_offset(pud, 0))
  73                         BUG();
  74         }
  75 #endif
  76         pud = pud_offset(pgd, 0);
  77         pmd_table = pmd_offset(pud, 0);
  78         return pmd_table;
  79 }
  80
  81 /*
  82  * Create a page table and place a pointer to it in a middle page
  83  * directory entry.
  84  */
  85 static pte_t * __init one_page_table_init(pmd_t *pmd)
  86 {
  87         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
  88                 pte_t *page_table = NULL;
  89
  90 #ifdef CONFIG_DEBUG_PAGEALLOC
  91                 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
  92 #endif
  93                 if (!page_table)
  94                         page_table =
  95                                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  96
  97                 paravirt_alloc_pt(&init_mm, __pa(page_table) >> PAGE_SHIFT);
  98                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
  99                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 100         }
 101
 102         return pte_offset_kernel(pmd, 0);
 103 }
 104
 105 /*
 106  * This function initializes a certain range of kernel virtual memory
 107  * with new bootmem page tables, everywhere page tables are missing in
 108  * the given range.
 109  */
 110
 111 /*
 112  * NOTE: The pagetables are allocated contiguous on the physical space
 113  * so we can cache the place of the first one and move around without
 114  * checking the pgd every time.
 115  */
 116 static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
 117 {
 118         pgd_t *pgd;
 119         pmd_t *pmd;
 120         int pgd_idx, pmd_idx;
 121         unsigned long vaddr;
 122
 123         vaddr = start;
 124         pgd_idx = pgd_index(vaddr);
 125         pmd_idx = pmd_index(vaddr);
 126         pgd = pgd_base + pgd_idx;
 127
 128         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 129                 pmd = one_md_table_init(pgd);
 130                 pmd = pmd + pmd_index(vaddr);
 131                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
 132                         one_page_table_init(pmd);
 133
 134                         vaddr += PMD_SIZE;
 135                 }
 136                 pmd_idx = 0;
 137         }
 138 }
 139
 140 static inline int is_kernel_text(unsigned long addr)
 141 {
 142         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 143                 return 1;
 144         return 0;
 145 }
 146
 147 /*
 148  * This maps the physical memory to kernel virtual address space, a total
 149  * of max_low_pfn pages, by creating page tables starting from address
 150  * PAGE_OFFSET.
 151  */
 152 static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 153 {
 154         unsigned long pfn;
 155         pgd_t *pgd;
 156         pmd_t *pmd;
 157         pte_t *pte;
 158         int pgd_idx, pmd_idx, pte_ofs;
 159
 160         pgd_idx = pgd_index(PAGE_OFFSET);
 161         pgd = pgd_base + pgd_idx;
 162         pfn = 0;
 163
 164         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 165                 pmd = one_md_table_init(pgd);
 166                 if (pfn >= max_low_pfn)
 167                         continue;
 168                 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
 169                         unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
 170
 171                         /* Map with big pages if possible, otherwise create normal page tables. */
 172                         if (cpu_has_pse) {
 173                                 unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
 174                                 if (is_kernel_text(address) || is_kernel_text(address2))
 175                                         set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
 176                                 else
 177                                         set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
 178
 179                                 pfn += PTRS_PER_PTE;
 180                         } else {
 181                                 pte = one_page_table_init(pmd);
 182
 183                                 for (pte_ofs = 0;
 184                                      pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
 185                                      pte++, pfn++, pte_ofs++, address += PAGE_SIZE) {
 186                                         if (is_kernel_text(address))
 187                                                 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 188                                         else
 189                                                 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
 190                                 }
 191                         }
 192                 }
 193         }
 194 }
 195
 196 static inline int page_kills_ppro(unsigned long pagenr)
 197 {
 198         if (pagenr >= 0x70000 && pagenr <= 0x7003F)
 199                 return 1;
 200         return 0;
 201 }
 202
 203 int page_is_ram(unsigned long pagenr)
 204 {
 205         int i;
 206         unsigned long addr, end;
 207
 208         if (efi_enabled) {
 209                 efi_memory_desc_t *md;
 210                 void *p;
 211
 212                 for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
 213                         md = p;
 214                         if (!is_available_memory(md))
 215                                 continue;
 216                         addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
 217                         end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;
 218
 219                         if ((pagenr >= addr) && (pagenr < end))
 220                                 return 1;
 221                 }
 222                 return 0;
 223         }
 224
 225         for (i = 0; i < e820.nr_map; i++) {
 226
 227                 if (e820.map[i].type != E820_RAM)       /* not usable memory */
 228                         continue;
 229                 /*
 230                  *      !!!FIXME!!! Some BIOSen report areas as RAM that
 231                  *      are not. Notably the 640->1Mb area. We need a sanity
 232                  *      check here.
 233                  */
 234                 addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
 235                 end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
 236                 if  ((pagenr >= addr) && (pagenr < end))
 237                         return 1;
 238         }
 239         return 0;
 240 }
 241
 242 #ifdef CONFIG_HIGHMEM
 243 pte_t *kmap_pte;
 244 pgprot_t kmap_prot;
 245
 246 #define kmap_get_fixmap_pte(vaddr)                                      \
 247         pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
 248
 249 static void __init kmap_init(void)
 250 {
 251         unsigned long kmap_vstart;
 252
 253         /* cache the first kmap pte */
 254         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 255         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 256
 257         kmap_prot = PAGE_KERNEL;
 258 }
 259
 260 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 261 {
 262         pgd_t *pgd;
 263         pud_t *pud;
 264         pmd_t *pmd;
 265         pte_t *pte;
 266         unsigned long vaddr;
 267
 268         vaddr = PKMAP_BASE;
 269         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 270
 271         pgd = swapper_pg_dir + pgd_index(vaddr);
 272         pud = pud_offset(pgd, vaddr);
 273         pmd = pmd_offset(pud, vaddr);
 274         pte = pte_offset_kernel(pmd, vaddr);
 275         pkmap_page_table = pte;
 276 }
 277
 278 static void __meminit free_new_highpage(struct page *page)
 279 {
 280         init_page_count(page);
 281         __free_page(page);
 282         totalhigh_pages++;
 283 }
 284
 285 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
 286 {
 287         if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
 288                 ClearPageReserved(page);
 289                 free_new_highpage(page);
 290         } else
 291                 SetPageReserved(page);
 292 }
 293
 294 static int __meminit add_one_highpage_hotplug(struct page *page, unsigned long pfn)
 295 {
 296         free_new_highpage(page);
 297         totalram_pages++;
 298 #ifdef CONFIG_FLATMEM
 299         max_mapnr = max(pfn, max_mapnr);
 300 #endif
 301         num_physpages++;
 302         return 0;
 303 }
 304
 305 /*
 306  * Not currently handling the NUMA case.
 307  * Assuming single node and all memory that
 308  * has been added dynamically that would be
 309  * onlined here is in HIGHMEM
 310  */
 311 void __meminit online_page(struct page *page)
 312 {
 313         ClearPageReserved(page);
 314         add_one_highpage_hotplug(page, page_to_pfn(page));
 315 }
 316
 317
 318 #ifdef CONFIG_NUMA
 319 extern void set_highmem_pages_init(int);
 320 #else
 321 static void __init set_highmem_pages_init(int bad_ppro)
 322 {
 323         int pfn;
 324         for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
 325                 add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
 326         totalram_pages += totalhigh_pages;
 327 }
 328 #endif /* CONFIG_FLATMEM */
 329
 330 #else
 331 #define kmap_init() do { } while (0)
 332 #define permanent_kmaps_init(pgd_base) do { } while (0)
 333 #define set_highmem_pages_init(bad_ppro) do { } while (0)
 334 #endif /* CONFIG_HIGHMEM */
 335
 336 unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
 337 EXPORT_SYMBOL(__PAGE_KERNEL);
 338 unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
 339
 340 #ifdef CONFIG_NUMA
 341 extern void __init remap_numa_kva(void);
 342 #else
 343 #define remap_numa_kva() do {} while (0)
 344 #endif
 345
 346 void __init native_pagetable_setup_start(pgd_t *base)
 347 {
 348 #ifdef CONFIG_X86_PAE
 349         int i;
 350
 351         /*
 352          * Init entries of the first-level page table to the
 353          * zero page, if they haven't already been set up.
 354          *
 355          * In a normal native boot, we'll be running on a
 356          * pagetable rooted in swapper_pg_dir, but not in PAE
 357          * mode, so this will end up clobbering the mappings
 358          * for the lower 24Mbytes of the address space,
 359          * without affecting the kernel address space.
 360          */
 361         for (i = 0; i < USER_PTRS_PER_PGD; i++)
 362                 set_pgd(&base[i],
 363                         __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
 364
 365         /* Make sure kernel address space is empty so that a pagetable
 366            will be allocated for it. */
 367         memset(&base[USER_PTRS_PER_PGD], 0,
 368                KERNEL_PGD_PTRS * sizeof(pgd_t));
 369 #else
 370         paravirt_alloc_pd(__pa(swapper_pg_dir) >> PAGE_SHIFT);
 371 #endif
 372 }
 373
 374 void __init native_pagetable_setup_done(pgd_t *base)
 375 {
 376 #ifdef CONFIG_X86_PAE
 377         /*
 378          * Add low memory identity-mappings - SMP needs it when
 379          * starting up on an AP from real-mode. In the non-PAE
 380          * case we already have these mappings through head.S.
 381          * All user-space mappings are explicitly cleared after
 382          * SMP startup.
 383          */
 384         set_pgd(&base[0], base[USER_PTRS_PER_PGD]);
 385 #endif
 386 }
 387
 388 /*
 389  * Build a proper pagetable for the kernel mappings.  Up until this
 390  * point, we've been running on some set of pagetables constructed by
 391  * the boot process.
 392  *
 393  * If we're booting on native hardware, this will be a pagetable
 394  * constructed in arch/i386/kernel/head.S, and not running in PAE mode
 395  * (even if we'll end up running in PAE).  The root of the pagetable
 396  * will be swapper_pg_dir.
 397  *
 398  * If we're booting paravirtualized under a hypervisor, then there are
 399  * more options: we may already be running PAE, and the pagetable may
 400  * or may not be based in swapper_pg_dir.  In any case,
 401  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 402  * appropriately for the rest of the initialization to work.
 403  *
 404  * In general, pagetable_init() assumes that the pagetable may already
 405  * be partially populated, and so it avoids stomping on any existing
 406  * mappings.
 407  */
 408 static void __init pagetable_init (void)
 409 {
 410         unsigned long vaddr, end;
 411         pgd_t *pgd_base = swapper_pg_dir;
 412
 413         paravirt_pagetable_setup_start(pgd_base);
 414
 415         /* Enable PSE if available */
 416         if (cpu_has_pse)
 417                 set_in_cr4(X86_CR4_PSE);
 418
 419         /* Enable PGE if available */
 420         if (cpu_has_pge) {
 421                 set_in_cr4(X86_CR4_PGE);
 422                 __PAGE_KERNEL |= _PAGE_GLOBAL;
 423                 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
 424         }
 425
 426         kernel_physical_mapping_init(pgd_base);
 427         remap_numa_kva();
 428
 429         /*
 430          * Fixed mappings, only the page table structure has to be
 431          * created - mappings will be set by set_fixmap():
 432          */
 433         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 434         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 435         page_table_range_init(vaddr, end, pgd_base);
 436
 437         permanent_kmaps_init(pgd_base);
 438
 439         paravirt_pagetable_setup_done(pgd_base);
 440 }
 441
 442 #if defined(CONFIG_HIBERNATION) || defined(CONFIG_ACPI)
 443 /*
 444  * Swap suspend & friends need this for resume because things like the intel-agp
 445  * driver might have split up a kernel 4MB mapping.
 446  */
 447 char __nosavedata swsusp_pg_dir[PAGE_SIZE]
 448         __attribute__ ((aligned (PAGE_SIZE)));
 449
 450 static inline void save_pg_dir(void)
 451 {
 452         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 453 }
 454 #else
 455 static inline void save_pg_dir(void)
 456 {
 457 }
 458 #endif
 459
 460 void zap_low_mappings (void)
 461 {
 462         int i;
 463
 464         save_pg_dir();
 465
 466         /*
 467          * Zap initial low-memory mappings.
 468          *
 469          * Note that "pgd_clear()" doesn't do it for
 470          * us, because pgd_clear() is a no-op on i386.
 471          */
 472         for (i = 0; i < USER_PTRS_PER_PGD; i++)
 473 #ifdef CONFIG_X86_PAE
 474                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 475 #else
 476                 set_pgd(swapper_pg_dir+i, __pgd(0));
 477 #endif
 478         flush_tlb_all();
 479 }
 480
 481 int nx_enabled = 0;
 482
 483 #ifdef CONFIG_X86_PAE
 484
 485 static int disable_nx __initdata = 0;
 486 u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
 487 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 488
 489 /*
 490  * noexec = on|off
 491  *
 492  * Control non executable mappings.
 493  *
 494  * on      Enable
 495  * off     Disable
 496  */
 497 static int __init noexec_setup(char *str)
 498 {
 499         if (!str || !strcmp(str, "on")) {
 500                 if (cpu_has_nx) {
 501                         __supported_pte_mask |= _PAGE_NX;
 502                         disable_nx = 0;
 503                 }
 504         } else if (!strcmp(str,"off")) {
 505                 disable_nx = 1;
 506                 __supported_pte_mask &= ~_PAGE_NX;
 507         } else
 508                 return -EINVAL;
 509
 510         return 0;
 511 }
 512 early_param("noexec", noexec_setup);
 513
 514 static void __init set_nx(void)
 515 {
 516         unsigned int v[4], l, h;
 517
 518         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 519                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 520                 if ((v[3] & (1 << 20)) && !disable_nx) {
 521                         rdmsr(MSR_EFER, l, h);
 522                         l |= EFER_NX;
 523                         wrmsr(MSR_EFER, l, h);
 524                         nx_enabled = 1;
 525                         __supported_pte_mask |= _PAGE_NX;
 526                 }
 527         }
 528 }
 529
 530 /*
 531  * Enables/disables executability of a given kernel page and
 532  * returns the previous setting.
 533  */
 534 int __init set_kernel_exec(unsigned long vaddr, int enable)
 535 {
 536         pte_t *pte;
 537         int ret = 1;
 538
 539         if (!nx_enabled)
 540                 goto out;
 541
 542         pte = lookup_address(vaddr);
 543         BUG_ON(!pte);
 544
 545         if (!pte_exec_kernel(*pte))
 546                 ret = 0;
 547
 548         if (enable)
 549                 pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
 550         else
 551                 pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
 552         pte_update_defer(&init_mm, vaddr, pte);
 553         __flush_tlb_all();
 554 out:
 555         return ret;
 556 }
 557
 558 #endif
 559
 560 /*
 561  * paging_init() sets up the page tables - note that the first 8MB are
 562  * already mapped by head.S.
 563  *
 564  * This routines also unmaps the page at virtual kernel address 0, so
 565  * that we can trap those pesky NULL-reference errors in the kernel.
 566  */
 567 void __init paging_init(void)
 568 {
 569 #ifdef CONFIG_X86_PAE
 570         set_nx();
 571         if (nx_enabled)
 572                 printk("NX (Execute Disable) protection: active\n");
 573 #endif
 574
 575         pagetable_init();
 576
 577         load_cr3(swapper_pg_dir);
 578
 579 #ifdef CONFIG_X86_PAE
 580         /*
 581          * We will bail out later - printk doesn't work right now so
 582          * the user would just see a hanging kernel.
 583          */
 584         if (cpu_has_pae)
 585                 set_in_cr4(X86_CR4_PAE);
 586 #endif
 587         __flush_tlb_all();
 588
 589         kmap_init();
 590 }
 591
 592 /*
 593  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 594  * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
 595  * used to involve black magic jumps to work around some nasty CPU bugs,
 596  * but fortunately the switch to using exceptions got rid of all that.
 597  */
 598
 599 static void __init test_wp_bit(void)
 600 {
 601         printk("Checking if this processor honours the WP bit even in supervisor mode... ");
 602
 603         /* Any page-aligned address will do, the test is non-destructive */
 604         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 605         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 606         clear_fixmap(FIX_WP_TEST);
 607
 608         if (!boot_cpu_data.wp_works_ok) {
 609                 printk("No.\n");
 610 #ifdef CONFIG_X86_WP_WORKS_OK
 611                 panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 612 #endif
 613         } else {
 614                 printk("Ok.\n");
 615         }
 616 }
 617
 618 static struct kcore_list kcore_mem, kcore_vmalloc;
 619
 620 void __init mem_init(void)
 621 {
 622         extern int ppro_with_ram_bug(void);
 623         int codesize, reservedpages, datasize, initsize;
 624         int tmp;
 625         int bad_ppro;
 626
 627 #ifdef CONFIG_FLATMEM
 628         BUG_ON(!mem_map);
 629 #endif
 630
 631         bad_ppro = ppro_with_ram_bug();
 632
 633 #ifdef CONFIG_HIGHMEM
 634         /* check that fixmap and pkmap do not overlap */
 635         if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
 636                 printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
 637                 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
 638                                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
 639                 BUG();
 640         }
 641 #endif
 642
 643         /* this will put all low memory onto the freelists */
 644         totalram_pages += free_all_bootmem();
 645
 646         reservedpages = 0;
 647         for (tmp = 0; tmp < max_low_pfn; tmp++)
 648                 /*
 649                  * Only count reserved RAM pages
 650                  */
 651                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 652                         reservedpages++;
 653
 654         set_highmem_pages_init(bad_ppro);
 655
 656         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 657         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 658         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 659
 660         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 661         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 662                    VMALLOC_END-VMALLOC_START);
 663
 664         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
 665                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 666                 num_physpages << (PAGE_SHIFT-10),
 667                 codesize >> 10,
 668                 reservedpages << (PAGE_SHIFT-10),
 669                 datasize >> 10,
 670                 initsize >> 10,
 671                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
 672                );
 673
 674 #if 1 /* double-sanity-check paranoia */
 675         printk("virtual kernel memory layout:\n"
 676                "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 677 #ifdef CONFIG_HIGHMEM
 678                "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 679 #endif
 680                "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 681                "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 682                "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 683                "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 684                "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
 685                FIXADDR_START, FIXADDR_TOP,
 686                (FIXADDR_TOP - FIXADDR_START) >> 10,
 687
 688 #ifdef CONFIG_HIGHMEM
 689                PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
 690                (LAST_PKMAP*PAGE_SIZE) >> 10,
 691 #endif
 692
 693                VMALLOC_START, VMALLOC_END,
 694                (VMALLOC_END - VMALLOC_START) >> 20,
 695
 696                (unsigned long)__va(0), (unsigned long)high_memory,
 697                ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
 698
 699                (unsigned long)&__init_begin, (unsigned long)&__init_end,
 700                ((unsigned long)&__init_end - (unsigned long)&__init_begin) >> 10,
 701
 702                (unsigned long)&_etext, (unsigned long)&_edata,
 703                ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
 704
 705                (unsigned long)&_text, (unsigned long)&_etext,
 706                ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
 707
 708 #ifdef CONFIG_HIGHMEM
 709         BUG_ON(PKMAP_BASE+LAST_PKMAP*PAGE_SIZE > FIXADDR_START);
 710         BUG_ON(VMALLOC_END                     > PKMAP_BASE);
 711 #endif
 712         BUG_ON(VMALLOC_START                   > VMALLOC_END);
 713         BUG_ON((unsigned long)high_memory      > VMALLOC_START);
 714 #endif /* double-sanity-check paranoia */
 715
 716 #ifdef CONFIG_X86_PAE
 717         if (!cpu_has_pae)
 718                 panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
 719 #endif
 720         if (boot_cpu_data.wp_works_ok < 0)
 721                 test_wp_bit();
 722
 723         /*
 724          * Subtle. SMP is doing it's boot stuff late (because it has to
 725          * fork idle threads) - but it also needs low mappings for the
 726          * protected-mode entry to work. We zap these entries only after
 727          * the WP-bit has been tested.
 728          */
 729 #ifndef CONFIG_SMP
 730         zap_low_mappings();
 731 #endif
 732 }
 733
 734 #ifdef CONFIG_MEMORY_HOTPLUG
 735 int arch_add_memory(int nid, u64 start, u64 size)
 736 {
 737         struct pglist_data *pgdata = NODE_DATA(nid);
 738         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
 739         unsigned long start_pfn = start >> PAGE_SHIFT;
 740         unsigned long nr_pages = size >> PAGE_SHIFT;
 741
 742         return __add_pages(zone, start_pfn, nr_pages);
 743 }
 744
 745 #endif
 746
 747 struct kmem_cache *pmd_cache;
 748
 749 void __init pgtable_cache_init(void)
 750 {
 751         if (PTRS_PER_PMD > 1)
 752                 pmd_cache = kmem_cache_create("pmd",
 753                                               PTRS_PER_PMD*sizeof(pmd_t),
 754                                               PTRS_PER_PMD*sizeof(pmd_t),
 755                                               SLAB_PANIC,
 756                                               pmd_ctor);
 757 }
 758
 759 /*
 760  * This function cannot be __init, since exceptions don't work in that
 761  * section.  Put this after the callers, so that it cannot be inlined.
 762  */
 763 static int noinline do_test_wp_bit(void)
 764 {
 765         char tmp_reg;
 766         int flag;
 767
 768         __asm__ __volatile__(
 769                 "       movb %0,%1      \n"
 770                 "1:     movb %1,%0      \n"
 771                 "       xorl %2,%2      \n"
 772                 "2:                     \n"
 773                 ".section __ex_table,\"a\"\n"
 774                 "       .align 4        \n"
 775                 "       .long 1b,2b     \n"
 776                 ".previous              \n"
 777                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
 778                  "=q" (tmp_reg),
 779                  "=r" (flag)
 780                 :"2" (1)
 781                 :"memory");
 782
 783         return flag;
 784 }
 785
 786 #ifdef CONFIG_DEBUG_RODATA
 787
 788 void mark_rodata_ro(void)
 789 {
 790         unsigned long start = PFN_ALIGN(_text);
 791         unsigned long size = PFN_ALIGN(_etext) - start;
 792
 793 #ifndef CONFIG_KPROBES
 794 #ifdef CONFIG_HOTPLUG_CPU
 795         /* It must still be possible to apply SMP alternatives. */
 796         if (num_possible_cpus() <= 1)
 797 #endif
 798         {
 799                 change_page_attr(virt_to_page(start),
 800                                  size >> PAGE_SHIFT, PAGE_KERNEL_RX);
 801                 printk("Write protecting the kernel text: %luk\n", size >> 10);
 802         }
 803 #endif
 804         start += size;
 805         size = (unsigned long)__end_rodata - start;
 806         change_page_attr(virt_to_page(start),
 807                          size >> PAGE_SHIFT, PAGE_KERNEL_RO);
 808         printk("Write protecting the kernel read-only data: %luk\n",
 809                size >> 10);
 810
 811         /*
 812          * change_page_attr() requires a global_flush_tlb() call after it.
 813          * We do this after the printk so that if something went wrong in the
 814          * change, the printk gets out at least to give a better debug hint
 815          * of who is the culprit.
 816          */
 817         global_flush_tlb();
 818 }
 819 #endif
 820
 821 void free_init_pages(char *what, unsigned long begin, unsigned long end)
 822 {
 823         unsigned long addr;
 824
 825         for (addr = begin; addr < end; addr += PAGE_SIZE) {
 826                 ClearPageReserved(virt_to_page(addr));
 827                 init_page_count(virt_to_page(addr));
 828                 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 829                 free_page(addr);
 830                 totalram_pages++;
 831         }
 832         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 833 }
 834
 835 void free_initmem(void)
 836 {
 837         free_init_pages("unused kernel memory",
 838                         (unsigned long)(&__init_begin),
 839                         (unsigned long)(&__init_end));
 840 }
 841
 842 #ifdef CONFIG_BLK_DEV_INITRD
 843 void free_initrd_mem(unsigned long start, unsigned long end)
 844 {
 845         free_init_pages("initrd memory", start, end);
 846 }
 847 #endif
 848