linux/arch/x86/mm/init_32.c
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   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/pfn.h>
  25#include <linux/poison.h>
  26#include <linux/bootmem.h>
  27#include <linux/slab.h>
  28#include <linux/proc_fs.h>
  29#include <linux/memory_hotplug.h>
  30#include <linux/initrd.h>
  31#include <linux/cpumask.h>
  32
  33#include <asm/asm.h>
  34#include <asm/bios_ebda.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#include <asm/smp.h>
  52
  53unsigned int __VMALLOC_RESERVE = 128 << 20;
  54
  55unsigned long max_low_pfn_mapped;
  56unsigned long max_pfn_mapped;
  57
  58DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
  59unsigned long highstart_pfn, highend_pfn;
  60
  61static noinline int do_test_wp_bit(void);
  62
  63
  64static unsigned long __initdata table_start;
  65static unsigned long __meminitdata table_end;
  66static unsigned long __meminitdata table_top;
  67
  68static int __initdata after_init_bootmem;
  69
  70static __init void *alloc_low_page(unsigned long *phys)
  71{
  72        unsigned long pfn = table_end++;
  73        void *adr;
  74
  75        if (pfn >= table_top)
  76                panic("alloc_low_page: ran out of memory");
  77
  78        adr = __va(pfn * PAGE_SIZE);
  79        memset(adr, 0, PAGE_SIZE);
  80        *phys  = pfn * PAGE_SIZE;
  81        return adr;
  82}
  83
  84/*
  85 * Creates a middle page table and puts a pointer to it in the
  86 * given global directory entry. This only returns the gd entry
  87 * in non-PAE compilation mode, since the middle layer is folded.
  88 */
  89static pmd_t * __init one_md_table_init(pgd_t *pgd)
  90{
  91        pud_t *pud;
  92        pmd_t *pmd_table;
  93
  94#ifdef CONFIG_X86_PAE
  95        unsigned long phys;
  96        if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
  97                if (after_init_bootmem)
  98                        pmd_table = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
  99                else
 100                        pmd_table = (pmd_t *)alloc_low_page(&phys);
 101                paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
 102                set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
 103                pud = pud_offset(pgd, 0);
 104                BUG_ON(pmd_table != pmd_offset(pud, 0));
 105        }
 106#endif
 107        pud = pud_offset(pgd, 0);
 108        pmd_table = pmd_offset(pud, 0);
 109
 110        return pmd_table;
 111}
 112
 113/*
 114 * Create a page table and place a pointer to it in a middle page
 115 * directory entry:
 116 */
 117static pte_t * __init one_page_table_init(pmd_t *pmd)
 118{
 119        if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
 120                pte_t *page_table = NULL;
 121
 122                if (after_init_bootmem) {
 123#ifdef CONFIG_DEBUG_PAGEALLOC
 124                        page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
 125#endif
 126                        if (!page_table)
 127                                page_table =
 128                                (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
 129                } else {
 130                        unsigned long phys;
 131                        page_table = (pte_t *)alloc_low_page(&phys);
 132                }
 133
 134                paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
 135                set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
 136                BUG_ON(page_table != pte_offset_kernel(pmd, 0));
 137        }
 138
 139        return pte_offset_kernel(pmd, 0);
 140}
 141
 142/*
 143 * This function initializes a certain range of kernel virtual memory
 144 * with new bootmem page tables, everywhere page tables are missing in
 145 * the given range.
 146 *
 147 * NOTE: The pagetables are allocated contiguous on the physical space
 148 * so we can cache the place of the first one and move around without
 149 * checking the pgd every time.
 150 */
 151static void __init
 152page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
 153{
 154        int pgd_idx, pmd_idx;
 155        unsigned long vaddr;
 156        pgd_t *pgd;
 157        pmd_t *pmd;
 158
 159        vaddr = start;
 160        pgd_idx = pgd_index(vaddr);
 161        pmd_idx = pmd_index(vaddr);
 162        pgd = pgd_base + pgd_idx;
 163
 164        for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
 165                pmd = one_md_table_init(pgd);
 166                pmd = pmd + pmd_index(vaddr);
 167                for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
 168                                                        pmd++, pmd_idx++) {
 169                        one_page_table_init(pmd);
 170
 171                        vaddr += PMD_SIZE;
 172                }
 173                pmd_idx = 0;
 174        }
 175}
 176
 177static inline int is_kernel_text(unsigned long addr)
 178{
 179        if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
 180                return 1;
 181        return 0;
 182}
 183
 184/*
 185 * This maps the physical memory to kernel virtual address space, a total
 186 * of max_low_pfn pages, by creating page tables starting from address
 187 * PAGE_OFFSET:
 188 */
 189static void __init kernel_physical_mapping_init(pgd_t *pgd_base,
 190                                                unsigned long start_pfn,
 191                                                unsigned long end_pfn,
 192                                                int use_pse)
 193{
 194        int pgd_idx, pmd_idx, pte_ofs;
 195        unsigned long pfn;
 196        pgd_t *pgd;
 197        pmd_t *pmd;
 198        pte_t *pte;
 199        unsigned pages_2m, pages_4k;
 200        int mapping_iter;
 201
 202        /*
 203         * First iteration will setup identity mapping using large/small pages
 204         * based on use_pse, with other attributes same as set by
 205         * the early code in head_32.S
 206         *
 207         * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
 208         * as desired for the kernel identity mapping.
 209         *
 210         * This two pass mechanism conforms to the TLB app note which says:
 211         *
 212         *     "Software should not write to a paging-structure entry in a way
 213         *      that would change, for any linear address, both the page size
 214         *      and either the page frame or attributes."
 215         */
 216        mapping_iter = 1;
 217
 218        if (!cpu_has_pse)
 219                use_pse = 0;
 220
 221repeat:
 222        pages_2m = pages_4k = 0;
 223        pfn = start_pfn;
 224        pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 225        pgd = pgd_base + pgd_idx;
 226        for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
 227                pmd = one_md_table_init(pgd);
 228
 229                if (pfn >= end_pfn)
 230                        continue;
 231#ifdef CONFIG_X86_PAE
 232                pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 233                pmd += pmd_idx;
 234#else
 235                pmd_idx = 0;
 236#endif
 237                for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
 238                     pmd++, pmd_idx++) {
 239                        unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;
 240
 241                        /*
 242                         * Map with big pages if possible, otherwise
 243                         * create normal page tables:
 244                         */
 245                        if (use_pse) {
 246                                unsigned int addr2;
 247                                pgprot_t prot = PAGE_KERNEL_LARGE;
 248                                /*
 249                                 * first pass will use the same initial
 250                                 * identity mapping attribute + _PAGE_PSE.
 251                                 */
 252                                pgprot_t init_prot =
 253                                        __pgprot(PTE_IDENT_ATTR |
 254                                                 _PAGE_PSE);
 255
 256                                addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
 257                                        PAGE_OFFSET + PAGE_SIZE-1;
 258
 259                                if (is_kernel_text(addr) ||
 260                                    is_kernel_text(addr2))
 261                                        prot = PAGE_KERNEL_LARGE_EXEC;
 262
 263                                pages_2m++;
 264                                if (mapping_iter == 1)
 265                                        set_pmd(pmd, pfn_pmd(pfn, init_prot));
 266                                else
 267                                        set_pmd(pmd, pfn_pmd(pfn, prot));
 268
 269                                pfn += PTRS_PER_PTE;
 270                                continue;
 271                        }
 272                        pte = one_page_table_init(pmd);
 273
 274                        pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
 275                        pte += pte_ofs;
 276                        for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
 277                             pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
 278                                pgprot_t prot = PAGE_KERNEL;
 279                                /*
 280                                 * first pass will use the same initial
 281                                 * identity mapping attribute.
 282                                 */
 283                                pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);
 284
 285                                if (is_kernel_text(addr))
 286                                        prot = PAGE_KERNEL_EXEC;
 287
 288                                pages_4k++;
 289                                if (mapping_iter == 1)
 290                                        set_pte(pte, pfn_pte(pfn, init_prot));
 291                                else
 292                                        set_pte(pte, pfn_pte(pfn, prot));
 293                        }
 294                }
 295        }
 296        if (mapping_iter == 1) {
 297                /*
 298                 * update direct mapping page count only in the first
 299                 * iteration.
 300                 */
 301                update_page_count(PG_LEVEL_2M, pages_2m);
 302                update_page_count(PG_LEVEL_4K, pages_4k);
 303
 304                /*
 305                 * local global flush tlb, which will flush the previous
 306                 * mappings present in both small and large page TLB's.
 307                 */
 308                __flush_tlb_all();
 309
 310                /*
 311                 * Second iteration will set the actual desired PTE attributes.
 312                 */
 313                mapping_iter = 2;
 314                goto repeat;
 315        }
 316}
 317
 318/*
 319 * devmem_is_allowed() checks to see if /dev/mem access to a certain address
 320 * is valid. The argument is a physical page number.
 321 *
 322 *
 323 * On x86, access has to be given to the first megabyte of ram because that area
 324 * contains bios code and data regions used by X and dosemu and similar apps.
 325 * Access has to be given to non-kernel-ram areas as well, these contain the PCI
 326 * mmio resources as well as potential bios/acpi data regions.
 327 */
 328int devmem_is_allowed(unsigned long pagenr)
 329{
 330        if (pagenr <= 256)
 331                return 1;
 332        if (!page_is_ram(pagenr))
 333                return 1;
 334        return 0;
 335}
 336
 337pte_t *kmap_pte;
 338pgprot_t kmap_prot;
 339
 340static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
 341{
 342        return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
 343                        vaddr), vaddr), vaddr);
 344}
 345
 346static void __init kmap_init(void)
 347{
 348        unsigned long kmap_vstart;
 349
 350        /*
 351         * Cache the first kmap pte:
 352         */
 353        kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
 354        kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
 355
 356        kmap_prot = PAGE_KERNEL;
 357}
 358
 359#ifdef CONFIG_HIGHMEM
 360static void __init permanent_kmaps_init(pgd_t *pgd_base)
 361{
 362        unsigned long vaddr;
 363        pgd_t *pgd;
 364        pud_t *pud;
 365        pmd_t *pmd;
 366        pte_t *pte;
 367
 368        vaddr = PKMAP_BASE;
 369        page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
 370
 371        pgd = swapper_pg_dir + pgd_index(vaddr);
 372        pud = pud_offset(pgd, vaddr);
 373        pmd = pmd_offset(pud, vaddr);
 374        pte = pte_offset_kernel(pmd, vaddr);
 375        pkmap_page_table = pte;
 376}
 377
 378static void __init add_one_highpage_init(struct page *page, int pfn)
 379{
 380        ClearPageReserved(page);
 381        init_page_count(page);
 382        __free_page(page);
 383        totalhigh_pages++;
 384}
 385
 386struct add_highpages_data {
 387        unsigned long start_pfn;
 388        unsigned long end_pfn;
 389};
 390
 391static int __init add_highpages_work_fn(unsigned long start_pfn,
 392                                         unsigned long end_pfn, void *datax)
 393{
 394        int node_pfn;
 395        struct page *page;
 396        unsigned long final_start_pfn, final_end_pfn;
 397        struct add_highpages_data *data;
 398
 399        data = (struct add_highpages_data *)datax;
 400
 401        final_start_pfn = max(start_pfn, data->start_pfn);
 402        final_end_pfn = min(end_pfn, data->end_pfn);
 403        if (final_start_pfn >= final_end_pfn)
 404                return 0;
 405
 406        for (node_pfn = final_start_pfn; node_pfn < final_end_pfn;
 407             node_pfn++) {
 408                if (!pfn_valid(node_pfn))
 409                        continue;
 410                page = pfn_to_page(node_pfn);
 411                add_one_highpage_init(page, node_pfn);
 412        }
 413
 414        return 0;
 415
 416}
 417
 418void __init add_highpages_with_active_regions(int nid, unsigned long start_pfn,
 419                                              unsigned long end_pfn)
 420{
 421        struct add_highpages_data data;
 422
 423        data.start_pfn = start_pfn;
 424        data.end_pfn = end_pfn;
 425
 426        work_with_active_regions(nid, add_highpages_work_fn, &data);
 427}
 428
 429#ifndef CONFIG_NUMA
 430static void __init set_highmem_pages_init(void)
 431{
 432        add_highpages_with_active_regions(0, highstart_pfn, highend_pfn);
 433
 434        totalram_pages += totalhigh_pages;
 435}
 436#endif /* !CONFIG_NUMA */
 437
 438#else
 439# define permanent_kmaps_init(pgd_base)         do { } while (0)
 440# define set_highmem_pages_init()       do { } while (0)
 441#endif /* CONFIG_HIGHMEM */
 442
 443void __init native_pagetable_setup_start(pgd_t *base)
 444{
 445        unsigned long pfn, va;
 446        pgd_t *pgd;
 447        pud_t *pud;
 448        pmd_t *pmd;
 449        pte_t *pte;
 450
 451        /*
 452         * Remove any mappings which extend past the end of physical
 453         * memory from the boot time page table:
 454         */
 455        for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
 456                va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
 457                pgd = base + pgd_index(va);
 458                if (!pgd_present(*pgd))
 459                        break;
 460
 461                pud = pud_offset(pgd, va);
 462                pmd = pmd_offset(pud, va);
 463                if (!pmd_present(*pmd))
 464                        break;
 465
 466                pte = pte_offset_kernel(pmd, va);
 467                if (!pte_present(*pte))
 468                        break;
 469
 470                pte_clear(NULL, va, pte);
 471        }
 472        paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
 473}
 474
 475void __init native_pagetable_setup_done(pgd_t *base)
 476{
 477}
 478
 479/*
 480 * Build a proper pagetable for the kernel mappings.  Up until this
 481 * point, we've been running on some set of pagetables constructed by
 482 * the boot process.
 483 *
 484 * If we're booting on native hardware, this will be a pagetable
 485 * constructed in arch/x86/kernel/head_32.S.  The root of the
 486 * pagetable will be swapper_pg_dir.
 487 *
 488 * If we're booting paravirtualized under a hypervisor, then there are
 489 * more options: we may already be running PAE, and the pagetable may
 490 * or may not be based in swapper_pg_dir.  In any case,
 491 * paravirt_pagetable_setup_start() will set up swapper_pg_dir
 492 * appropriately for the rest of the initialization to work.
 493 *
 494 * In general, pagetable_init() assumes that the pagetable may already
 495 * be partially populated, and so it avoids stomping on any existing
 496 * mappings.
 497 */
 498static void __init early_ioremap_page_table_range_init(pgd_t *pgd_base)
 499{
 500        unsigned long vaddr, end;
 501
 502        /*
 503         * Fixed mappings, only the page table structure has to be
 504         * created - mappings will be set by set_fixmap():
 505         */
 506        early_ioremap_clear();
 507        vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
 508        end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
 509        page_table_range_init(vaddr, end, pgd_base);
 510        early_ioremap_reset();
 511}
 512
 513static void __init pagetable_init(void)
 514{
 515        pgd_t *pgd_base = swapper_pg_dir;
 516
 517        permanent_kmaps_init(pgd_base);
 518}
 519
 520#ifdef CONFIG_ACPI_SLEEP
 521/*
 522 * ACPI suspend needs this for resume, because things like the intel-agp
 523 * driver might have split up a kernel 4MB mapping.
 524 */
 525char swsusp_pg_dir[PAGE_SIZE]
 526        __attribute__ ((aligned(PAGE_SIZE)));
 527
 528static inline void save_pg_dir(void)
 529{
 530        memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
 531}
 532#else /* !CONFIG_ACPI_SLEEP */
 533static inline void save_pg_dir(void)
 534{
 535}
 536#endif /* !CONFIG_ACPI_SLEEP */
 537
 538void zap_low_mappings(void)
 539{
 540        int i;
 541
 542        /*
 543         * Zap initial low-memory mappings.
 544         *
 545         * Note that "pgd_clear()" doesn't do it for
 546         * us, because pgd_clear() is a no-op on i386.
 547         */
 548        for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
 549#ifdef CONFIG_X86_PAE
 550                set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
 551#else
 552                set_pgd(swapper_pg_dir+i, __pgd(0));
 553#endif
 554        }
 555        flush_tlb_all();
 556}
 557
 558int nx_enabled;
 559
 560pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
 561EXPORT_SYMBOL_GPL(__supported_pte_mask);
 562
 563#ifdef CONFIG_X86_PAE
 564
 565static int disable_nx __initdata;
 566
 567/*
 568 * noexec = on|off
 569 *
 570 * Control non executable mappings.
 571 *
 572 * on      Enable
 573 * off     Disable
 574 */
 575static int __init noexec_setup(char *str)
 576{
 577        if (!str || !strcmp(str, "on")) {
 578                if (cpu_has_nx) {
 579                        __supported_pte_mask |= _PAGE_NX;
 580                        disable_nx = 0;
 581                }
 582        } else {
 583                if (!strcmp(str, "off")) {
 584                        disable_nx = 1;
 585                        __supported_pte_mask &= ~_PAGE_NX;
 586                } else {
 587                        return -EINVAL;
 588                }
 589        }
 590
 591        return 0;
 592}
 593early_param("noexec", noexec_setup);
 594
 595static void __init set_nx(void)
 596{
 597        unsigned int v[4], l, h;
 598
 599        if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
 600                cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
 601
 602                if ((v[3] & (1 << 20)) && !disable_nx) {
 603                        rdmsr(MSR_EFER, l, h);
 604                        l |= EFER_NX;
 605                        wrmsr(MSR_EFER, l, h);
 606                        nx_enabled = 1;
 607                        __supported_pte_mask |= _PAGE_NX;
 608                }
 609        }
 610}
 611#endif
 612
 613/* user-defined highmem size */
 614static unsigned int highmem_pages = -1;
 615
 616/*
 617 * highmem=size forces highmem to be exactly 'size' bytes.
 618 * This works even on boxes that have no highmem otherwise.
 619 * This also works to reduce highmem size on bigger boxes.
 620 */
 621static int __init parse_highmem(char *arg)
 622{
 623        if (!arg)
 624                return -EINVAL;
 625
 626        highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
 627        return 0;
 628}
 629early_param("highmem", parse_highmem);
 630
 631/*
 632 * Determine low and high memory ranges:
 633 */
 634void __init find_low_pfn_range(void)
 635{
 636        /* it could update max_pfn */
 637
 638        /* max_low_pfn is 0, we already have early_res support */
 639
 640        max_low_pfn = max_pfn;
 641        if (max_low_pfn > MAXMEM_PFN) {
 642                if (highmem_pages == -1)
 643                        highmem_pages = max_pfn - MAXMEM_PFN;
 644                if (highmem_pages + MAXMEM_PFN < max_pfn)
 645                        max_pfn = MAXMEM_PFN + highmem_pages;
 646                if (highmem_pages + MAXMEM_PFN > max_pfn) {
 647                        printk(KERN_WARNING "only %luMB highmem pages "
 648                                "available, ignoring highmem size of %uMB.\n",
 649                                pages_to_mb(max_pfn - MAXMEM_PFN),
 650                                pages_to_mb(highmem_pages));
 651                        highmem_pages = 0;
 652                }
 653                max_low_pfn = MAXMEM_PFN;
 654#ifndef CONFIG_HIGHMEM
 655                /* Maximum memory usable is what is directly addressable */
 656                printk(KERN_WARNING "Warning only %ldMB will be used.\n",
 657                                        MAXMEM>>20);
 658                if (max_pfn > MAX_NONPAE_PFN)
 659                        printk(KERN_WARNING
 660                                 "Use a HIGHMEM64G enabled kernel.\n");
 661                else
 662                        printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
 663                max_pfn = MAXMEM_PFN;
 664#else /* !CONFIG_HIGHMEM */
 665#ifndef CONFIG_HIGHMEM64G
 666                if (max_pfn > MAX_NONPAE_PFN) {
 667                        max_pfn = MAX_NONPAE_PFN;
 668                        printk(KERN_WARNING "Warning only 4GB will be used."
 669                                "Use a HIGHMEM64G enabled kernel.\n");
 670                }
 671#endif /* !CONFIG_HIGHMEM64G */
 672#endif /* !CONFIG_HIGHMEM */
 673        } else {
 674                if (highmem_pages == -1)
 675                        highmem_pages = 0;
 676#ifdef CONFIG_HIGHMEM
 677                if (highmem_pages >= max_pfn) {
 678                        printk(KERN_ERR "highmem size specified (%uMB) is "
 679                                "bigger than pages available (%luMB)!.\n",
 680                                pages_to_mb(highmem_pages),
 681                                pages_to_mb(max_pfn));
 682                        highmem_pages = 0;
 683                }
 684                if (highmem_pages) {
 685                        if (max_low_pfn - highmem_pages <
 686                            64*1024*1024/PAGE_SIZE){
 687                                printk(KERN_ERR "highmem size %uMB results in "
 688                                "smaller than 64MB lowmem, ignoring it.\n"
 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"
 697                                        " kernel!\n");
 698#endif
 699        }
 700}
 701
 702#ifndef CONFIG_NEED_MULTIPLE_NODES
 703void __init initmem_init(unsigned long start_pfn,
 704                                  unsigned long end_pfn)
 705{
 706#ifdef CONFIG_HIGHMEM
 707        highstart_pfn = highend_pfn = max_pfn;
 708        if (max_pfn > max_low_pfn)
 709                highstart_pfn = max_low_pfn;
 710        memory_present(0, 0, highend_pfn);
 711        e820_register_active_regions(0, 0, highend_pfn);
 712        printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
 713                pages_to_mb(highend_pfn - highstart_pfn));
 714        num_physpages = highend_pfn;
 715        high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
 716#else
 717        memory_present(0, 0, max_low_pfn);
 718        e820_register_active_regions(0, 0, max_low_pfn);
 719        num_physpages = max_low_pfn;
 720        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
 721#endif
 722#ifdef CONFIG_FLATMEM
 723        max_mapnr = num_physpages;
 724#endif
 725        printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
 726                        pages_to_mb(max_low_pfn));
 727
 728        setup_bootmem_allocator();
 729}
 730#endif /* !CONFIG_NEED_MULTIPLE_NODES */
 731
 732static void __init zone_sizes_init(void)
 733{
 734        unsigned long max_zone_pfns[MAX_NR_ZONES];
 735        memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 736        max_zone_pfns[ZONE_DMA] =
 737                virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 738        max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 739#ifdef CONFIG_HIGHMEM
 740        max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 741#endif
 742
 743        free_area_init_nodes(max_zone_pfns);
 744}
 745
 746void __init setup_bootmem_allocator(void)
 747{
 748        int i;
 749        unsigned long bootmap_size, bootmap;
 750        /*
 751         * Initialize the boot-time allocator (with low memory only):
 752         */
 753        bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
 754        bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
 755                                 max_pfn_mapped<<PAGE_SHIFT, bootmap_size,
 756                                 PAGE_SIZE);
 757        if (bootmap == -1L)
 758                panic("Cannot find bootmem map of size %ld\n", bootmap_size);
 759        reserve_early(bootmap, bootmap + bootmap_size, "BOOTMAP");
 760
 761        /* don't touch min_low_pfn */
 762        bootmap_size = init_bootmem_node(NODE_DATA(0), bootmap >> PAGE_SHIFT,
 763                                         min_low_pfn, max_low_pfn);
 764        printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
 765                 max_pfn_mapped<<PAGE_SHIFT);
 766        printk(KERN_INFO "  low ram: %08lx - %08lx\n",
 767                 min_low_pfn<<PAGE_SHIFT, max_low_pfn<<PAGE_SHIFT);
 768        printk(KERN_INFO "  bootmap %08lx - %08lx\n",
 769                 bootmap, bootmap + bootmap_size);
 770        for_each_online_node(i)
 771                free_bootmem_with_active_regions(i, max_low_pfn);
 772        early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
 773
 774        after_init_bootmem = 1;
 775}
 776
 777static void __init find_early_table_space(unsigned long end, int use_pse)
 778{
 779        unsigned long puds, pmds, ptes, tables, start;
 780
 781        puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
 782        tables = PAGE_ALIGN(puds * sizeof(pud_t));
 783
 784        pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
 785        tables += PAGE_ALIGN(pmds * sizeof(pmd_t));
 786
 787        if (use_pse) {
 788                unsigned long extra;
 789
 790                extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
 791                extra += PMD_SIZE;
 792                ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
 793        } else
 794                ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
 795
 796        tables += PAGE_ALIGN(ptes * sizeof(pte_t));
 797
 798        /* for fixmap */
 799        tables += PAGE_SIZE * 2;
 800
 801        /*
 802         * RED-PEN putting page tables only on node 0 could
 803         * cause a hotspot and fill up ZONE_DMA. The page tables
 804         * need roughly 0.5KB per GB.
 805         */
 806        start = 0x7000;
 807        table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
 808                                        tables, PAGE_SIZE);
 809        if (table_start == -1UL)
 810                panic("Cannot find space for the kernel page tables");
 811
 812        table_start >>= PAGE_SHIFT;
 813        table_end = table_start;
 814        table_top = table_start + (tables>>PAGE_SHIFT);
 815
 816        printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
 817                end, table_start << PAGE_SHIFT,
 818                (table_start << PAGE_SHIFT) + tables);
 819}
 820
 821unsigned long __init_refok init_memory_mapping(unsigned long start,
 822                                                unsigned long end)
 823{
 824        pgd_t *pgd_base = swapper_pg_dir;
 825        unsigned long start_pfn, end_pfn;
 826        unsigned long big_page_start;
 827#ifdef CONFIG_DEBUG_PAGEALLOC
 828        /*
 829         * For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
 830         * This will simplify cpa(), which otherwise needs to support splitting
 831         * large pages into small in interrupt context, etc.
 832         */
 833        int use_pse = 0;
 834#else
 835        int use_pse = cpu_has_pse;
 836#endif
 837
 838        /*
 839         * Find space for the kernel direct mapping tables.
 840         */
 841        if (!after_init_bootmem)
 842                find_early_table_space(end, use_pse);
 843
 844#ifdef CONFIG_X86_PAE
 845        set_nx();
 846        if (nx_enabled)
 847                printk(KERN_INFO "NX (Execute Disable) protection: active\n");
 848#endif
 849
 850        /* Enable PSE if available */
 851        if (cpu_has_pse)
 852                set_in_cr4(X86_CR4_PSE);
 853
 854        /* Enable PGE if available */
 855        if (cpu_has_pge) {
 856                set_in_cr4(X86_CR4_PGE);
 857                __supported_pte_mask |= _PAGE_GLOBAL;
 858        }
 859
 860        /*
 861         * Don't use a large page for the first 2/4MB of memory
 862         * because there are often fixed size MTRRs in there
 863         * and overlapping MTRRs into large pages can cause
 864         * slowdowns.
 865         */
 866        big_page_start = PMD_SIZE;
 867
 868        if (start < big_page_start) {
 869                start_pfn = start >> PAGE_SHIFT;
 870                end_pfn = min(big_page_start>>PAGE_SHIFT, end>>PAGE_SHIFT);
 871        } else {
 872                /* head is not big page alignment ? */
 873                start_pfn = start >> PAGE_SHIFT;
 874                end_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 875                                 << (PMD_SHIFT - PAGE_SHIFT);
 876        }
 877        if (start_pfn < end_pfn)
 878                kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn, 0);
 879
 880        /* big page range */
 881        start_pfn = ((start + (PMD_SIZE - 1))>>PMD_SHIFT)
 882                         << (PMD_SHIFT - PAGE_SHIFT);
 883        if (start_pfn < (big_page_start >> PAGE_SHIFT))
 884                start_pfn =  big_page_start >> PAGE_SHIFT;
 885        end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
 886        if (start_pfn < end_pfn)
 887                kernel_physical_mapping_init(pgd_base, start_pfn, end_pfn,
 888                                             use_pse);
 889
 890        /* tail is not big page alignment ? */
 891        start_pfn = end_pfn;
 892        if (start_pfn > (big_page_start>>PAGE_SHIFT)) {
 893                end_pfn = end >> PAGE_SHIFT;
 894                if (start_pfn < end_pfn)
 895                        kernel_physical_mapping_init(pgd_base, start_pfn,
 896                                                         end_pfn, 0);
 897        }
 898
 899        early_ioremap_page_table_range_init(pgd_base);
 900
 901        load_cr3(swapper_pg_dir);
 902
 903        __flush_tlb_all();
 904
 905        if (!after_init_bootmem)
 906                reserve_early(table_start << PAGE_SHIFT,
 907                                 table_end << PAGE_SHIFT, "PGTABLE");
 908
 909        if (!after_init_bootmem)
 910                early_memtest(start, end);
 911
 912        return end >> PAGE_SHIFT;
 913}
 914
 915
 916/*
 917 * paging_init() sets up the page tables - note that the first 8MB are
 918 * already mapped by head.S.
 919 *
 920 * This routines also unmaps the page at virtual kernel address 0, so
 921 * that we can trap those pesky NULL-reference errors in the kernel.
 922 */
 923void __init paging_init(void)
 924{
 925        pagetable_init();
 926
 927        __flush_tlb_all();
 928
 929        kmap_init();
 930
 931        /*
 932         * NOTE: at this point the bootmem allocator is fully available.
 933         */
 934        sparse_init();
 935        zone_sizes_init();
 936}
 937
 938/*
 939 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 940 * and also on some strange 486's. All 586+'s are OK. This used to involve
 941 * black magic jumps to work around some nasty CPU bugs, but fortunately the
 942 * switch to using exceptions got rid of all that.
 943 */
 944static void __init test_wp_bit(void)
 945{
 946        printk(KERN_INFO
 947  "Checking if this processor honours the WP bit even in supervisor mode...");
 948
 949        /* Any page-aligned address will do, the test is non-destructive */
 950        __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
 951        boot_cpu_data.wp_works_ok = do_test_wp_bit();
 952        clear_fixmap(FIX_WP_TEST);
 953
 954        if (!boot_cpu_data.wp_works_ok) {
 955                printk(KERN_CONT "No.\n");
 956#ifdef CONFIG_X86_WP_WORKS_OK
 957                panic(
 958  "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
 959#endif
 960        } else {
 961                printk(KERN_CONT "Ok.\n");
 962        }
 963}
 964
 965static struct kcore_list kcore_mem, kcore_vmalloc;
 966
 967void __init mem_init(void)
 968{
 969        int codesize, reservedpages, datasize, initsize;
 970        int tmp;
 971
 972        start_periodic_check_for_corruption();
 973
 974#ifdef CONFIG_FLATMEM
 975        BUG_ON(!mem_map);
 976#endif
 977        /* this will put all low memory onto the freelists */
 978        totalram_pages += free_all_bootmem();
 979
 980        reservedpages = 0;
 981        for (tmp = 0; tmp < max_low_pfn; tmp++)
 982                /*
 983                 * Only count reserved RAM pages:
 984                 */
 985                if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 986                        reservedpages++;
 987
 988        set_highmem_pages_init();
 989
 990        codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 991        datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 992        initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
 993
 994        kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
 995        kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
 996                   VMALLOC_END-VMALLOC_START);
 997
 998        printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
 999                        "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
1000                (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
1001                num_physpages << (PAGE_SHIFT-10),
1002                codesize >> 10,
1003                reservedpages << (PAGE_SHIFT-10),
1004                datasize >> 10,
1005                initsize >> 10,
1006                (unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
1007               );
1008
1009        printk(KERN_INFO "virtual kernel memory layout:\n"
1010                "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1011#ifdef CONFIG_HIGHMEM
1012                "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1013#endif
1014                "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1015                "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
1016                "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1017                "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
1018                "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
1019                FIXADDR_START, FIXADDR_TOP,
1020                (FIXADDR_TOP - FIXADDR_START) >> 10,
1021
1022#ifdef CONFIG_HIGHMEM
1023                PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
1024                (LAST_PKMAP*PAGE_SIZE) >> 10,
1025#endif
1026
1027                VMALLOC_START, VMALLOC_END,
1028                (VMALLOC_END - VMALLOC_START) >> 20,
1029
1030                (unsigned long)__va(0), (unsigned long)high_memory,
1031                ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,
1032
1033                (unsigned long)&__init_begin, (unsigned long)&__init_end,
1034                ((unsigned long)&__init_end -
1035                 (unsigned long)&__init_begin) >> 10,
1036
1037                (unsigned long)&_etext, (unsigned long)&_edata,
1038                ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,
1039
1040                (unsigned long)&_text, (unsigned long)&_etext,
1041                ((unsigned long)&_etext - (unsigned long)&_text) >> 10);
1042
1043#ifdef CONFIG_HIGHMEM
1044        BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE        > FIXADDR_START);
1045        BUG_ON(VMALLOC_END                              > PKMAP_BASE);
1046#endif
1047        BUG_ON(VMALLOC_START                            > VMALLOC_END);
1048        BUG_ON((unsigned long)high_memory               > VMALLOC_START);
1049
1050        if (boot_cpu_data.wp_works_ok < 0)
1051                test_wp_bit();
1052
1053        save_pg_dir();
1054        zap_low_mappings();
1055}
1056
1057#ifdef CONFIG_MEMORY_HOTPLUG
1058int arch_add_memory(int nid, u64 start, u64 size)
1059{
1060        struct pglist_data *pgdata = NODE_DATA(nid);
1061        struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
1062        unsigned long start_pfn = start >> PAGE_SHIFT;
1063        unsigned long nr_pages = size >> PAGE_SHIFT;
1064
1065        return __add_pages(zone, start_pfn, nr_pages);
1066}
1067#endif
1068
1069/*
1070 * This function cannot be __init, since exceptions don't work in that
1071 * section.  Put this after the callers, so that it cannot be inlined.
1072 */
1073static noinline int do_test_wp_bit(void)
1074{
1075        char tmp_reg;
1076        int flag;
1077
1078        __asm__ __volatile__(
1079                "       movb %0, %1     \n"
1080                "1:     movb %1, %0     \n"
1081                "       xorl %2, %2     \n"
1082                "2:                     \n"
1083                _ASM_EXTABLE(1b,2b)
1084                :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
1085                 "=q" (tmp_reg),
1086                 "=r" (flag)
1087                :"2" (1)
1088                :"memory");
1089
1090        return flag;
1091}
1092
1093#ifdef CONFIG_DEBUG_RODATA
1094const int rodata_test_data = 0xC3;
1095EXPORT_SYMBOL_GPL(rodata_test_data);
1096
1097void mark_rodata_ro(void)
1098{
1099        unsigned long start = PFN_ALIGN(_text);
1100        unsigned long size = PFN_ALIGN(_etext) - start;
1101
1102#ifndef CONFIG_DYNAMIC_FTRACE
1103        /* Dynamic tracing modifies the kernel text section */
1104        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1105        printk(KERN_INFO "Write protecting the kernel text: %luk\n",
1106                size >> 10);
1107
1108#ifdef CONFIG_CPA_DEBUG
1109        printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
1110                start, start+size);
1111        set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);
1112
1113        printk(KERN_INFO "Testing CPA: write protecting again\n");
1114        set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
1115#endif
1116#endif /* CONFIG_DYNAMIC_FTRACE */
1117
1118        start += size;
1119        size = (unsigned long)__end_rodata - start;
1120        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1121        printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
1122                size >> 10);
1123        rodata_test();
1124
1125#ifdef CONFIG_CPA_DEBUG
1126        printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
1127        set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
1128
1129        printk(KERN_INFO "Testing CPA: write protecting again\n");
1130        set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
1131#endif
1132}
1133#endif
1134
1135void free_init_pages(char *what, unsigned long begin, unsigned long end)
1136{
1137#ifdef CONFIG_DEBUG_PAGEALLOC
1138        /*
1139         * If debugging page accesses then do not free this memory but
1140         * mark them not present - any buggy init-section access will
1141         * create a kernel page fault:
1142         */
1143        printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
1144                begin, PAGE_ALIGN(end));
1145        set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
1146#else
1147        unsigned long addr;
1148
1149        /*
1150         * We just marked the kernel text read only above, now that
1151         * we are going to free part of that, we need to make that
1152         * writeable first.
1153         */
1154        set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
1155
1156        for (addr = begin; addr < end; addr += PAGE_SIZE) {
1157                ClearPageReserved(virt_to_page(addr));
1158                init_page_count(virt_to_page(addr));
1159                memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE);
1160                free_page(addr);
1161                totalram_pages++;
1162        }
1163        printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
1164#endif
1165}
1166
1167void free_initmem(void)
1168{
1169        free_init_pages("unused kernel memory",
1170                        (unsigned long)(&__init_begin),
1171                        (unsigned long)(&__init_end));
1172}
1173
1174#ifdef CONFIG_BLK_DEV_INITRD
1175void free_initrd_mem(unsigned long start, unsigned long end)
1176{
1177        free_init_pages("initrd memory", start, end);
1178}
1179#endif
1180
1181int __init reserve_bootmem_generic(unsigned long phys, unsigned long len,
1182                                   int flags)
1183{
1184        return reserve_bootmem(phys, len, flags);
1185}
1186