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/asm.h>
  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/bugs.h>
  44 #include <asm/tlb.h>
  45 #include <asm/tlbflush.h>
  46 #include <asm/pgalloc.h>
  47 #include <asm/sections.h>
  48 #include <asm/paravirt.h>
  49 #include <asm/setup.h>
  50 #include <asm/cacheflush.h>
  51
  52 unsigned int __VMALLOC_RESERVE = 128 << 20;
  53
  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  * Creates a middle page table and puts a pointer to it in the
  63  * given global directory entry. This only returns the gd entry
  64  * in non-PAE compilation mode, since the middle layer is folded.
  65  */
  66 static pmd_t * __init one_md_table_init(pgd_t *pgd)
  67 {
  68         pud_t *pud;
  69         pmd_t *pmd_table;
  70
  71 #ifdef CONFIG_X86_PAE
  72         if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  73                 pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
  74
  75                 paravirt_alloc_pd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
  76                 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
  77                 pud = pud_offset(pgd, 0);
  78                 BUG_ON(pmd_table != pmd_offset(pud, 0));
  79         }
  80 #endif
  81         pud = pud_offset(pgd, 0);
  82         pmd_table = pmd_offset(pud, 0);
  83
  84         return pmd_table;
  85 }
  86
  87 /*
  88  * Create a page table and place a pointer to it in a middle page
  89  * directory entry:
  90  */
  91 static pte_t * __init one_page_table_init(pmd_t *pmd)
  92 {
  93         if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
  94                 pte_t *page_table = NULL;
  95
  96 #ifdef CONFIG_DEBUG_PAGEALLOC
  97                 page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
  98 #endif
  99                 if (!page_table) {
 100                         page_table =
 101                                 (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 102                 }
 103
 104                 paravirt_alloc_pt(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 105                 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 106                 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 107         }
 108
 109         return pte_offset_kernel(pmd, 0);
 110 }
 111
 112 /*
 113  * This function initializes a certain range of kernel virtual memory
 114  * with new bootmem page tables, everywhere page tables are missing in
 115  * the given range.
 116  *
 117  * NOTE: The pagetables are allocated contiguous on the physical space
 118  * so we can cache the place of the first one and move around without
 119  * checking the pgd every time.
 120  */
 121 static void __init
 122 page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 123 {
 124         int pgd_idx, pmd_idx;
 125         unsigned long vaddr;
 126         pgd_t *pgd;
 127         pmd_t *pmd;
 128
 129         vaddr = start;
 130         pgd_idx = pgd_index(vaddr);
 131         pmd_idx = pmd_index(vaddr);
 132         pgd = pgd_base + pgd_idx;
 133
 134         for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 135                 pmd = one_md_table_init(pgd);
 136                 pmd = pmd + pmd_index(vaddr);
 137                 for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 138                                                         pmd++, pmd_idx++) {
 139                         one_page_table_init(pmd);
 140
 141                         vaddr += PMD_SIZE;
 142                 }
 143                 pmd_idx = 0;
 144         }
 145 }
 146
 147 static inline int is_kernel_text(unsigned long addr)
 148 {
 149         if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 150                 return 1;
 151         return 0;
 152 }
 153
 154 /*
 155  * This maps the physical memory to kernel virtual address space, a total
 156  * of max_low_pfn pages, by creating page tables starting from address
 157  * PAGE_OFFSET:
 158  */
 159 static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
 160 {
 161         int pgd_idx, pmd_idx, pte_ofs;
 162         unsigned long pfn;
 163         pgd_t *pgd;
 164         pmd_t *pmd;
 165         pte_t *pte;
 166
 167         pgd_idx = pgd_index(PAGE_OFFSET);
 168         pgd = pgd_base + pgd_idx;
 169         pfn = 0;
 170
 171         for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 172                 pmd = one_md_table_init(pgd);
 173                 if (pfn >= max_low_pfn)
 174                         continue;
 175
 176                 for (pmd_idx = 0;
 177                      pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn;
 178                      pmd++, pmd_idx++) {
 179                         unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 180
 181                         /*
 182                          * Map with big pages if possible, otherwise
 183                          * create normal page tables:
 184                          *
 185                          * Don't use a large page for the first 2/4MB of memory
 186                          * because there are often fixed size MTRRs in there
 187                          * and overlapping MTRRs into large pages can cause
 188                          * slowdowns.
 189                          */
 190                         if (cpu_has_pse && !(pgd_idx == 0 && pmd_idx == 0)) {
 191                                 unsigned int addr2;
 192                                 pgprot_t prot = PAGE_KERNEL_LARGE;
 193
 194                                 addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 195                                         PAGE_OFFSET + PAGE_SIZE-1;
 196
 197                                 if (is_kernel_text(addr) ||
 198                                     is_kernel_text(addr2))
 199                                         prot = PAGE_KERNEL_LARGE_EXEC;
 200
 201                                 set_pmd(pmd, pfn_pmd(pfn, prot));
 202
 203                                 pfn += PTRS_PER_PTE;
 204                                 max_pfn_mapped = pfn;
 205                                 continue;
 206                         }
 207                         pte = one_page_table_init(pmd);
 208
 209                         for (pte_ofs = 0;
 210                              pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn;
 211                              pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 212                                 pgprot_t prot = PAGE_KERNEL;
 213
 214                                 if (is_kernel_text(addr))
 215                                         prot = PAGE_KERNEL_EXEC;
 216
 217                                 set_pte(pte, pfn_pte(pfn, prot));
 218                         }
 219                         max_pfn_mapped = pfn;
 220                 }
 221         }
 222 }
 223
 224 static inline int page_kills_ppro(unsigned long pagenr)
 225 {
 226         if (pagenr >= 0x70000 && pagenr <= 0x7003F)
 227                 return 1;
 228         return 0;
 229 }
 230
 231 #ifdef CONFIG_HIGHMEM
 232 pte_t *kmap_pte;
 233 pgprot_t kmap_prot;
 234
 235 static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 236 {
 237         return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 238                         vaddr), vaddr), vaddr);
 239 }
 240
 241 static void __init kmap_init(void)
 242 {
 243         unsigned long kmap_vstart;
 244
 245         /*
 246          * Cache the first kmap pte:
 247          */
 248         kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 249         kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 250
 251         kmap_prot = PAGE_KERNEL;
 252 }
 253
 254 static void __init permanent_kmaps_init(pgd_t *pgd_base)
 255 {
 256         unsigned long vaddr;
 257         pgd_t *pgd;
 258         pud_t *pud;
 259         pmd_t *pmd;
 260         pte_t *pte;
 261
 262         vaddr = PKMAP_BASE;
 263         page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 264
 265         pgd = swapper_pg_dir + pgd_index(vaddr);
 266         pud = pud_offset(pgd, vaddr);
 267         pmd = pmd_offset(pud, vaddr);
 268         pte = pte_offset_kernel(pmd, vaddr);
 269         pkmap_page_table = pte;
 270 }
 271
 272 static void __meminit free_new_highpage(struct page *page)
 273 {
 274         init_page_count(page);
 275         __free_page(page);
 276         totalhigh_pages++;
 277 }
 278
 279 void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
 280 {
 281         if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
 282                 ClearPageReserved(page);
 283                 free_new_highpage(page);
 284         } else
 285                 SetPageReserved(page);
 286 }
 287
 288 static int __meminit
 289 add_one_highpage_hotplug(struct page *page, unsigned long pfn)
 290 {
 291         free_new_highpage(page);
 292         totalram_pages++;
 293 #ifdef CONFIG_FLATMEM
 294         max_mapnr = max(pfn, max_mapnr);
 295 #endif
 296         num_physpages++;
 297
 298         return 0;
 299 }
 300
 301 /*
 302  * Not currently handling the NUMA case.
 303  * Assuming single node and all memory that
 304  * has been added dynamically that would be
 305  * onlined here is in HIGHMEM.
 306  */
 307 void __meminit online_page(struct page *page)
 308 {
 309         ClearPageReserved(page);
 310         add_one_highpage_hotplug(page, page_to_pfn(page));
 311 }
 312
 313 #ifndef CONFIG_NUMA
 314 static void __init set_highmem_pages_init(int bad_ppro)
 315 {
 316         int pfn;
 317
 318         for (pfn = highstart_pfn; pfn < highend_pfn; pfn++) {
 319                 /*
 320                  * Holes under sparsemem might not have no mem_map[]:
 321                  */
 322                 if (pfn_valid(pfn))
 323                         add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
 324         }
 325         totalram_pages += totalhigh_pages;
 326 }
 327 #endif /* !CONFIG_NUMA */
 328
 329 #else
 330 # define kmap_init()                            do { } while (0)
 331 # define permanent_kmaps_init(pgd_base)         do { } while (0)
 332 # define set_highmem_pages_init(bad_ppro)       do { } while (0)
 333 #endif /* CONFIG_HIGHMEM */
 334
 335 pteval_t __PAGE_KERNEL = _PAGE_KERNEL;
 336 EXPORT_SYMBOL(__PAGE_KERNEL);
 337
 338 pteval_t __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
 339
 340 void __init native_pagetable_setup_start(pgd_t *base)
 341 {
 342         unsigned long pfn, va;
 343         pgd_t *pgd;
 344         pud_t *pud;
 345         pmd_t *pmd;
 346         pte_t *pte;
 347
 348         /*
 349          * Remove any mappings which extend past the end of physical
 350          * memory from the boot time page table:
 351          */
 352         for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 353                 va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 354                 pgd = base + pgd_index(va);
 355                 if (!pgd_present(*pgd))
 356                         break;
 357
 358                 pud = pud_offset(pgd, va);
 359                 pmd = pmd_offset(pud, va);
 360                 if (!pmd_present(*pmd))
 361                         break;
 362
 363                 pte = pte_offset_kernel(pmd, va);
 364                 if (!pte_present(*pte))
 365                         break;
 366
 367                 pte_clear(NULL, va, pte);
 368         }
 369         paravirt_alloc_pd(&init_mm, __pa(base) >> PAGE_SHIFT);
 370 }
 371
 372 void __init native_pagetable_setup_done(pgd_t *base)
 373 {
 374 }
 375
 376 /*
 377  * Build a proper pagetable for the kernel mappings.  Up until this
 378  * point, we've been running on some set of pagetables constructed by
 379  * the boot process.
 380  *
 381  * If we're booting on native hardware, this will be a pagetable
 382  * constructed in arch/x86/kernel/head_32.S.  The root of the
 383  * pagetable will be swapper_pg_dir.
 384  *
 385  * If we're booting paravirtualized under a hypervisor, then there are
 386  * more options: we may already be running PAE, and the pagetable may
 387  * or may not be based in swapper_pg_dir.  In any case,
 388  * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 389  * appropriately for the rest of the initialization to work.
 390  *
 391  * In general, pagetable_init() assumes that the pagetable may already
 392  * be partially populated, and so it avoids stomping on any existing
 393  * mappings.
 394  */
 395 static void __init pagetable_init(void)
 396 {
 397         pgd_t *pgd_base = swapper_pg_dir;
 398         unsigned long vaddr, end;
 399
 400         paravirt_pagetable_setup_start(pgd_base);
 401
 402         /* Enable PSE if available */
 403         if (cpu_has_pse)
 404                 set_in_cr4(X86_CR4_PSE);
 405
 406         /* Enable PGE if available */
 407         if (cpu_has_pge) {
 408                 set_in_cr4(X86_CR4_PGE);
 409                 __PAGE_KERNEL |= _PAGE_GLOBAL;
 410                 __PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
 411         }
 412
 413         kernel_physical_mapping_init(pgd_base);
 414         remap_numa_kva();
 415
 416         /*
 417          * Fixed mappings, only the page table structure has to be
 418          * created - mappings will be set by set_fixmap():
 419          */
 420         early_ioremap_clear();
 421         vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 422         end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 423         page_table_range_init(vaddr, end, pgd_base);
 424         early_ioremap_reset();
 425
 426         permanent_kmaps_init(pgd_base);
 427
 428         paravirt_pagetable_setup_done(pgd_base);
 429 }
 430
 431 #ifdef CONFIG_ACPI_SLEEP
 432 /*
 433  * ACPI suspend needs this for resume, because things like the intel-agp
 434  * driver might have split up a kernel 4MB mapping.
 435  */
 436 char swsusp_pg_dir[PAGE_SIZE]
 437         __attribute__ ((aligned(PAGE_SIZE)));
 438
 439 static inline void save_pg_dir(void)
 440 {
 441         memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 442 }
 443 #else /* !CONFIG_ACPI_SLEEP */
 444 static inline void save_pg_dir(void)
 445 {
 446 }
 447 #endif /* !CONFIG_ACPI_SLEEP */
 448
 449 void zap_low_mappings(void)
 450 {
 451         int i;
 452
 453         save_pg_dir();
 454
 455         /*
 456          * Zap initial low-memory mappings.
 457          *
 458          * Note that "pgd_clear()" doesn't do it for
 459          * us, because pgd_clear() is a no-op on i386.
 460          */
 461         for (i = 0; i < USER_PTRS_PER_PGD; i++) {
 462 #ifdef CONFIG_X86_PAE
 463                 set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 464 #else
 465                 set_pgd(swapper_pg_dir+i, __pgd(0));
 466 #endif
 467         }
 468         flush_tlb_all();
 469 }
 470
 471 int nx_enabled;
 472
 473 pteval_t __supported_pte_mask __read_mostly = ~_PAGE_NX;
 474 EXPORT_SYMBOL_GPL(__supported_pte_mask);
 475
 476 #ifdef CONFIG_X86_PAE
 477
 478 static int disable_nx __initdata;
 479
 480 /*
 481  * noexec = on|off
 482  *
 483  * Control non executable mappings.
 484  *
 485  * on      Enable
 486  * off     Disable
 487  */
 488 static int __init noexec_setup(char *str)
 489 {
 490         if (!str || !strcmp(str, "on")) {
 491                 if (cpu_has_nx) {
 492                         __supported_pte_mask |= _PAGE_NX;
 493                         disable_nx = 0;
 494                 }
 495         } else {
 496                 if (!strcmp(str, "off")) {
 497                         disable_nx = 1;
 498                         __supported_pte_mask &= ~_PAGE_NX;
 499                 } else {
 500                         return -EINVAL;
 501                 }
 502         }
 503
 504         return 0;
 505 }
 506 early_param("noexec", noexec_setup);
 507
 508 static void __init set_nx(void)
 509 {
 510         unsigned int v[4], l, h;
 511
 512         if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 513                 cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 514
 515                 if ((v[3] & (1 << 20)) && !disable_nx) {
 516                         rdmsr(MSR_EFER, l, h);
 517                         l |= EFER_NX;
 518                         wrmsr(MSR_EFER, l, h);
 519                         nx_enabled = 1;
 520                         __supported_pte_mask |= _PAGE_NX;
 521                 }
 522         }
 523 }
 524 #endif
 525
 526 /*
 527  * paging_init() sets up the page tables - note that the first 8MB are
 528  * already mapped by head.S.
 529  *
 530  * This routines also unmaps the page at virtual kernel address 0, so
 531  * that we can trap those pesky NULL-reference errors in the kernel.
 532  */
 533 void __init paging_init(void)
 534 {
 535 #ifdef CONFIG_X86_PAE
 536         set_nx();
 537         if (nx_enabled)
 538                 printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 539 #endif
 540         pagetable_init();
 541
 542         load_cr3(swapper_pg_dir);
 543
 544         __flush_tlb_all();
 545
 546         kmap_init();
 547 }
 548
 549 /*
 550  * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 551  * and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
 552  * used to involve black magic jumps to work around some nasty CPU bugs,
 553  * but fortunately the switch to using exceptions got rid of all that.
 554  */
 555 static void __init test_wp_bit(void)
 556 {
 557         printk(KERN_INFO
 558   "Checking if this processor honours the WP bit even in supervisor mode...");
 559
 560         /* Any page-aligned address will do, the test is non-destructive */
 561         __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 562         boot_cpu_data.wp_works_ok = do_test_wp_bit();
 563         clear_fixmap(FIX_WP_TEST);
 564
 565         if (!boot_cpu_data.wp_works_ok) {
 566                 printk(KERN_CONT "No.\n");
 567 #ifdef CONFIG_X86_WP_WORKS_OK
 568                 panic(
 569   "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 570 #endif
 571         } else {
 572                 printk(KERN_CONT "Ok.\n");
 573         }
 574 }
 575
 576 static struct kcore_list kcore_mem, kcore_vmalloc;
 577
 578 void __init mem_init(void)
 579 {
 580         int codesize, reservedpages, datasize, initsize;
 581         int tmp, bad_ppro;
 582
 583 #ifdef CONFIG_FLATMEM
 584         BUG_ON(!mem_map);
 585 #endif
 586         bad_ppro = ppro_with_ram_bug();
 587
 588 #ifdef CONFIG_HIGHMEM
 589         /* check that fixmap and pkmap do not overlap */
 590         if (PKMAP_BASE + LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
 591                 printk(KERN_ERR
 592                         "fixmap and kmap areas overlap - this will crash\n");
 593                 printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
 594                                 PKMAP_BASE, PKMAP_BASE + LAST_PKMAP*PAGE_SIZE,
 595                                 FIXADDR_START);
 596                 BUG();
 597         }
 598 #endif
 599         /* this will put all low memory onto the freelists */
 600         totalram_pages += free_all_bootmem();
 601
 602         reservedpages = 0;
 603         for (tmp = 0; tmp < max_low_pfn; tmp++)
 604                 /*
 605                  * Only count reserved RAM pages:
 606                  */
 607                 if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 608                         reservedpages++;
 609
 610         set_highmem_pages_init(bad_ppro);
 611
 612         codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 613         datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 614         initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 615
 616         kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 617         kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 618                    VMALLOC_END-VMALLOC_START);
 619
 620         printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
 621                         "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
 622                 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
 623                 num_physpages << (PAGE_SHIFT-10),
 624                 codesize >> 10,
 625                 reservedpages << (PAGE_SHIFT-10),
 626                 datasize >> 10,
 627                 initsize >> 10,
 628                 (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
 629                );
 630
 631 #if 1 /* double-sanity-check paranoia */
 632         printk(KERN_INFO "virtual kernel memory layout:\n"
 633                 "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 634 #ifdef CONFIG_HIGHMEM
 635                 "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 636 #endif
 637                 "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 638                 "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
 639                 "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 640                 "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
 641                 "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
 642                 FIXADDR_START, FIXADDR_TOP,
 643                 (FIXADDR_TOP - FIXADDR_START) >> 10,
 644
 645 #ifdef CONFIG_HIGHMEM
 646                 PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
 647                 (LAST_PKMAP*PAGE_SIZE) >> 10,
 648 #endif
 649
 650                 VMALLOC_START, VMALLOC_END,
 651                 (VMALLOC_END - VMALLOC_START) >> 20,
 652
 653                 (unsigned long)__va(0), (unsigned long)high_memory,
 654                 ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
 655
 656                 (unsigned long)&__init_begin, (unsigned long)&__init_end,
 657                 ((unsigned long)&__init_end -
 658                  (unsigned long)&__init_begin) >> 10,
 659
 660                 (unsigned long)&_etext, (unsigned long)&_edata,
 661                 ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
 662
 663                 (unsigned long)&_text, (unsigned long)&_etext,
 664                 ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
 665
 666 #ifdef CONFIG_HIGHMEM
 667         BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
 668         BUG_ON(VMALLOC_END                              > PKMAP_BASE);
 669 #endif
 670         BUG_ON(VMALLOC_START                            > VMALLOC_END);
 671         BUG_ON((unsigned long)high_memory               > VMALLOC_START);
 672 #endif /* double-sanity-check paranoia */
 673
 674         if (boot_cpu_data.wp_works_ok < 0)
 675                 test_wp_bit();
 676
 677         cpa_init();
 678
 679         /*
 680          * Subtle. SMP is doing it's boot stuff late (because it has to
 681          * fork idle threads) - but it also needs low mappings for the
 682          * protected-mode entry to work. We zap these entries only after
 683          * the WP-bit has been tested.
 684          */
 685 #ifndef CONFIG_SMP
 686         zap_low_mappings();
 687 #endif
 688 }
 689
 690 #ifdef CONFIG_MEMORY_HOTPLUG
 691 int arch_add_memory(int nid, u64 start, u64 size)
 692 {
 693         struct pglist_data *pgdata = NODE_DATA(nid);
 694         struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
 695         unsigned long start_pfn = start >> PAGE_SHIFT;
 696         unsigned long nr_pages = size >> PAGE_SHIFT;
 697
 698         return __add_pages(zone, start_pfn, nr_pages);
 699 }
 700 #endif
 701
 702 /*
 703  * This function cannot be __init, since exceptions don't work in that
 704  * section.  Put this after the callers, so that it cannot be inlined.
 705  */
 706 static noinline int do_test_wp_bit(void)
 707 {
 708         char tmp_reg;
 709         int flag;
 710
 711         __asm__ __volatile__(
 712                 "       movb %0, %1     \n"
 713                 "1:     movb %1, %0     \n"
 714                 "       xorl %2, %2     \n"
 715                 "2:                     \n"
 716                 _ASM_EXTABLE(1b,2b)
 717                 :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
 718                  "=q" (tmp_reg),
 719                  "=r" (flag)
 720                 :"2" (1)
 721                 :"memory");
 722
 723         return flag;
 724 }
 725
 726 #ifdef CONFIG_DEBUG_RODATA
 727 const int rodata_test_data = 0xC3;
 728 EXPORT_SYMBOL_GPL(rodata_test_data);
 729
 730 void mark_rodata_ro(void)
 731 {
 732         unsigned long start = PFN_ALIGN(_text);
 733         unsigned long size = PFN_ALIGN(_etext) - start;
 734
 735         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 736         printk(KERN_INFO "Write protecting the kernel text: %luk\n",
 737                 size >> 10);
 738
 739 #ifdef CONFIG_CPA_DEBUG
 740         printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
 741                 start, start+size);
 742         set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
 743
 744         printk(KERN_INFO "Testing CPA: write protecting again\n");
 745         set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
 746 #endif
 747         start += size;
 748         size = (unsigned long)__end_rodata - start;
 749         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 750         printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
 751                 size >> 10);
 752         rodata_test();
 753
 754 #ifdef CONFIG_CPA_DEBUG
 755         printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
 756         set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
 757
 758         printk(KERN_INFO "Testing CPA: write protecting again\n");
 759         set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
 760 #endif
 761 }
 762 #endif
 763
 764 void free_init_pages(char *what, unsigned long begin, unsigned long end)
 765 {
 766 #ifdef CONFIG_DEBUG_PAGEALLOC
 767         /*
 768          * If debugging page accesses then do not free this memory but
 769          * mark them not present - any buggy init-section access will
 770          * create a kernel page fault:
 771          */
 772         printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
 773                 begin, PAGE_ALIGN(end));
 774         set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
 775 #else
 776         unsigned long addr;
 777
 778         /*
 779          * We just marked the kernel text read only above, now that
 780          * we are going to free part of that, we need to make that
 781          * writeable first.
 782          */
 783         set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
 784
 785         for (addr = begin; addr < end; addr += PAGE_SIZE) {
 786                 ClearPageReserved(virt_to_page(addr));
 787                 init_page_count(virt_to_page(addr));
 788                 memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
 789                 free_page(addr);
 790                 totalram_pages++;
 791         }
 792         printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
 793 #endif
 794 }
 795
 796 void free_initmem(void)
 797 {
 798         free_init_pages("unused kernel memory",
 799                         (unsigned long)(&__init_begin),
 800                         (unsigned long)(&__init_end));
 801 }
 802
 803 #ifdef CONFIG_BLK_DEV_INITRD
 804 void free_initrd_mem(unsigned long start, unsigned long end)
 805 {
 806         free_init_pages("initrd memory", start, end);
 807 }
 808 #endif