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