init_32.c

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/*
 *
 *  Copyright (C) 1995  Linus Torvalds
 *
 *  Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
 */

#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/pci.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/proc_fs.h>
#include <linux/memory_hotplug.h>
#include <linux/initrd.h>
#include <linux/cpumask.h>
#include <linux/gfp.h>

#include <asm/asm.h>
#include <asm/bios_ebda.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/apic.h>
#include <asm/bugs.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/olpc_ofw.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/paravirt.h>
#include <asm/setup.h>
#include <asm/cacheflush.h>
#include <asm/page_types.h>
#include <asm/init.h>

unsigned long highstart_pfn, highend_pfn;

static noinline int do_test_wp_bit(void);

bool __read_mostly __vmalloc_start_set = false;

static __init void *alloc_low_page(void)
{
    unsigned long pfn = pgt_buf_end++;
    void *adr;

    if (pfn >= pgt_buf_top)
        panic("alloc_low_page: ran out of memory");

    adr = __va(pfn * PAGE_SIZE);
    clear_page(adr);
    return adr;
}

/*
 * Creates a middle page table and puts a pointer to it in the
 * given global directory entry. This only returns the gd entry
 * in non-PAE compilation mode, since the middle layer is folded.
 */
static pmd_t * __init one_md_table_init(pgd_t *pgd)
{
    pud_t *pud;
    pmd_t *pmd_table;

#ifdef CONFIG_X86_PAE
    if (!(pgd_val(*pgd) & _PAGE_PRESENT)) {
        if (after_bootmem)
            pmd_table = (pmd_t *)alloc_bootmem_pages(PAGE_SIZE);
        else
            pmd_table = (pmd_t *)alloc_low_page();
        paravirt_alloc_pmd(&init_mm, __pa(pmd_table) >> PAGE_SHIFT);
        set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
        pud = pud_offset(pgd, 0);
        BUG_ON(pmd_table != pmd_offset(pud, 0));

        return pmd_table;
    }
#endif
    pud = pud_offset(pgd, 0);
    pmd_table = pmd_offset(pud, 0);

    return pmd_table;
}

/*
 * Create a page table and place a pointer to it in a middle page
 * directory entry:
 */
static pte_t * __init one_page_table_init(pmd_t *pmd)
{
    if (!(pmd_val(*pmd) & _PAGE_PRESENT)) {
        pte_t *page_table = NULL;

        if (after_bootmem) {
#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KMEMCHECK)
            page_table = (pte_t *) alloc_bootmem_pages(PAGE_SIZE);
#endif
            if (!page_table)
                page_table =
                (pte_t *)alloc_bootmem_pages(PAGE_SIZE);
        } else
            page_table = (pte_t *)alloc_low_page();

        paravirt_alloc_pte(&init_mm, __pa(page_table) >> PAGE_SHIFT);
        set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
        BUG_ON(page_table != pte_offset_kernel(pmd, 0));
    }

    return pte_offset_kernel(pmd, 0);
}

pmd_t * __init populate_extra_pmd(unsigned long vaddr)
{
    int pgd_idx = pgd_index(vaddr);
    int pmd_idx = pmd_index(vaddr);

    return one_md_table_init(swapper_pg_dir + pgd_idx) + pmd_idx;
}

pte_t * __init populate_extra_pte(unsigned long vaddr)
{
    int pte_idx = pte_index(vaddr);
    pmd_t *pmd;

    pmd = populate_extra_pmd(vaddr);
    return one_page_table_init(pmd) + pte_idx;
}

static pte_t *__init page_table_kmap_check(pte_t *pte, pmd_t *pmd,
                       unsigned long vaddr, pte_t *lastpte)
{
#ifdef CONFIG_HIGHMEM
    /*
     * Something (early fixmap) may already have put a pte
     * page here, which causes the page table allocation
     * to become nonlinear. Attempt to fix it, and if it
     * is still nonlinear then we have to bug.
     */
    int pmd_idx_kmap_begin = fix_to_virt(FIX_KMAP_END) >> PMD_SHIFT;
    int pmd_idx_kmap_end = fix_to_virt(FIX_KMAP_BEGIN) >> PMD_SHIFT;

    if (pmd_idx_kmap_begin != pmd_idx_kmap_end
        && (vaddr >> PMD_SHIFT) >= pmd_idx_kmap_begin
        && (vaddr >> PMD_SHIFT) <= pmd_idx_kmap_end
        && ((__pa(pte) >> PAGE_SHIFT) < pgt_buf_start
        || (__pa(pte) >> PAGE_SHIFT) >= pgt_buf_end)) {
        pte_t *newpte;
        int i;

        BUG_ON(after_bootmem);
        newpte = alloc_low_page();
        for (i = 0; i < PTRS_PER_PTE; i++)
            set_pte(newpte + i, pte[i]);

        paravirt_alloc_pte(&init_mm, __pa(newpte) >> PAGE_SHIFT);
        set_pmd(pmd, __pmd(__pa(newpte)|_PAGE_TABLE));
        BUG_ON(newpte != pte_offset_kernel(pmd, 0));
        __flush_tlb_all();

        paravirt_release_pte(__pa(pte) >> PAGE_SHIFT);
        pte = newpte;
    }
    BUG_ON(vaddr < fix_to_virt(FIX_KMAP_BEGIN - 1)
           && vaddr > fix_to_virt(FIX_KMAP_END)
           && lastpte && lastpte + PTRS_PER_PTE != pte);
#endif
    return pte;
}

/*
 * This function initializes a certain range of kernel virtual memory
 * with new bootmem page tables, everywhere page tables are missing in
 * the given range.
 *
 * NOTE: The pagetables are allocated contiguous on the physical space
 * so we can cache the place of the first one and move around without
 * checking the pgd every time.
 */
static void __init
page_table_range_init(unsigned long start, unsigned long end, pgd_t *pgd_base)
{
    int pgd_idx, pmd_idx;
    unsigned long vaddr;
    pgd_t *pgd;
    pmd_t *pmd;
    pte_t *pte = NULL;

    vaddr = start;
    pgd_idx = pgd_index(vaddr);
    pmd_idx = pmd_index(vaddr);
    pgd = pgd_base + pgd_idx;

    for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
        pmd = one_md_table_init(pgd);
        pmd = pmd + pmd_index(vaddr);
        for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end);
                            pmd++, pmd_idx++) {
            pte = page_table_kmap_check(one_page_table_init(pmd),
                                        pmd, vaddr, pte);

            vaddr += PMD_SIZE;
        }
        pmd_idx = 0;
    }
}

static inline int is_kernel_text(unsigned long addr)
{
    if (addr >= (unsigned long)_text && addr <= (unsigned long)__init_end)
        return 1;
    return 0;
}

/*
 * This maps the physical memory to kernel virtual address space, a total
 * of max_low_pfn pages, by creating page tables starting from address
 * PAGE_OFFSET:
 */
unsigned long __init
kernel_physical_mapping_init(unsigned long start,
                 unsigned long end,
                 unsigned long page_size_mask)
{
    int use_pse = page_size_mask == (1<<PG_LEVEL_2M);
    unsigned long last_map_addr = end;
    unsigned long start_pfn, end_pfn;
    pgd_t *pgd_base = swapper_pg_dir;
    int pgd_idx, pmd_idx, pte_ofs;
    unsigned long pfn;
    pgd_t *pgd;
    pmd_t *pmd;
    pte_t *pte;
    unsigned pages_2m, pages_4k;
    int mapping_iter;

    start_pfn = start >> PAGE_SHIFT;
    end_pfn = end >> PAGE_SHIFT;

    /*
     * First iteration will setup identity mapping using large/small pages
     * based on use_pse, with other attributes same as set by
     * the early code in head_32.S
     *
     * Second iteration will setup the appropriate attributes (NX, GLOBAL..)
     * as desired for the kernel identity mapping.
     *
     * This two pass mechanism conforms to the TLB app note which says:
     *
     *     "Software should not write to a paging-structure entry in a way
     *      that would change, for any linear address, both the page size
     *      and either the page frame or attributes."
     */
    mapping_iter = 1;

    if (!cpu_has_pse)
        use_pse = 0;

repeat:
    pages_2m = pages_4k = 0;
    pfn = start_pfn;
    pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
    pgd = pgd_base + pgd_idx;
    for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
        pmd = one_md_table_init(pgd);

        if (pfn >= end_pfn)
            continue;
#ifdef CONFIG_X86_PAE
        pmd_idx = pmd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
        pmd += pmd_idx;
#else
        pmd_idx = 0;
#endif
        for (; pmd_idx < PTRS_PER_PMD && pfn < end_pfn;
             pmd++, pmd_idx++) {
            unsigned int addr = pfn * PAGE_SIZE + PAGE_OFFSET;

            /*
             * Map with big pages if possible, otherwise
             * create normal page tables:
             */
            if (use_pse) {
                unsigned int addr2;
                pgprot_t prot = PAGE_KERNEL_LARGE;
                /*
                 * first pass will use the same initial
                 * identity mapping attribute + _PAGE_PSE.
                 */
                pgprot_t init_prot =
                    __pgprot(PTE_IDENT_ATTR |
                         _PAGE_PSE);

                addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE +
                    PAGE_OFFSET + PAGE_SIZE-1;

                if (is_kernel_text(addr) ||
                    is_kernel_text(addr2))
                    prot = PAGE_KERNEL_LARGE_EXEC;

                pages_2m++;
                if (mapping_iter == 1)
                    set_pmd(pmd, pfn_pmd(pfn, init_prot));
                else
                    set_pmd(pmd, pfn_pmd(pfn, prot));

                pfn += PTRS_PER_PTE;
                continue;
            }
            pte = one_page_table_init(pmd);

            pte_ofs = pte_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET);
            pte += pte_ofs;
            for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn;
                 pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) {
                pgprot_t prot = PAGE_KERNEL;
                /*
                 * first pass will use the same initial
                 * identity mapping attribute.
                 */
                pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR);

                if (is_kernel_text(addr))
                    prot = PAGE_KERNEL_EXEC;

                pages_4k++;
                if (mapping_iter == 1) {
                    set_pte(pte, pfn_pte(pfn, init_prot));
                    last_map_addr = (pfn << PAGE_SHIFT) + PAGE_SIZE;
                } else
                    set_pte(pte, pfn_pte(pfn, prot));
            }
        }
    }
    if (mapping_iter == 1) {
        /*
         * update direct mapping page count only in the first
         * iteration.
         */
        update_page_count(PG_LEVEL_2M, pages_2m);
        update_page_count(PG_LEVEL_4K, pages_4k);

        /*
         * local global flush tlb, which will flush the previous
         * mappings present in both small and large page TLB's.
         */
        __flush_tlb_all();

        /*
         * Second iteration will set the actual desired PTE attributes.
         */
        mapping_iter = 2;
        goto repeat;
    }
    return last_map_addr;
}

pte_t *kmap_pte;
pgprot_t kmap_prot;

static inline pte_t *kmap_get_fixmap_pte(unsigned long vaddr)
{
    return pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr),
            vaddr), vaddr), vaddr);
}

static void __init kmap_init(void)
{
    unsigned long kmap_vstart;

    /*
     * Cache the first kmap pte:
     */
    kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
    kmap_pte = kmap_get_fixmap_pte(kmap_vstart);

    kmap_prot = PAGE_KERNEL;
}

#ifdef CONFIG_HIGHMEM
static void __init permanent_kmaps_init(pgd_t *pgd_base)
{
    unsigned long vaddr;
    pgd_t *pgd;
    pud_t *pud;
    pmd_t *pmd;
    pte_t *pte;

    vaddr = PKMAP_BASE;
    page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);

    pgd = swapper_pg_dir + pgd_index(vaddr);
    pud = pud_offset(pgd, vaddr);
    pmd = pmd_offset(pud, vaddr);
    pte = pte_offset_kernel(pmd, vaddr);
    pkmap_page_table = pte;
}

static void __init add_one_highpage_init(struct page *page)
{
    ClearPageReserved(page);
    init_page_count(page);
    __free_page(page);
    totalhigh_pages++;
}

void __init add_highpages_with_active_regions(int nid,
             unsigned long start_pfn, unsigned long end_pfn)
{
    phys_addr_t start, end;
    u64 i;

    for_each_free_mem_range(i, nid, &start, &end, NULL) {
        unsigned long pfn = clamp_t(unsigned long, PFN_UP(start),
                        start_pfn, end_pfn);
        unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end),
                          start_pfn, end_pfn);
        for ( ; pfn < e_pfn; pfn++)
            if (pfn_valid(pfn))
                add_one_highpage_init(pfn_to_page(pfn));
    }
}
#else
static inline void permanent_kmaps_init(pgd_t *pgd_base)
{
}
#endif /* CONFIG_HIGHMEM */

void __init native_pagetable_init(void)
{
    unsigned long pfn, va;
    pgd_t *pgd, *base = swapper_pg_dir;
    pud_t *pud;
    pmd_t *pmd;
    pte_t *pte;

    /*
     * Remove any mappings which extend past the end of physical
     * memory from the boot time page table:
     */
    for (pfn = max_low_pfn + 1; pfn < 1<<(32-PAGE_SHIFT); pfn++) {
        va = PAGE_OFFSET + (pfn<<PAGE_SHIFT);
        pgd = base + pgd_index(va);
        if (!pgd_present(*pgd))
            break;

        pud = pud_offset(pgd, va);
        pmd = pmd_offset(pud, va);
        if (!pmd_present(*pmd))
            break;

        pte = pte_offset_kernel(pmd, va);
        if (!pte_present(*pte))
            break;

        pte_clear(NULL, va, pte);
    }
    paravirt_alloc_pmd(&init_mm, __pa(base) >> PAGE_SHIFT);
    paging_init();
}

/*
 * Build a proper pagetable for the kernel mappings.  Up until this
 * point, we've been running on some set of pagetables constructed by
 * the boot process.
 *
 * If we're booting on native hardware, this will be a pagetable
 * constructed in arch/x86/kernel/head_32.S.  The root of the
 * pagetable will be swapper_pg_dir.
 *
 * If we're booting paravirtualized under a hypervisor, then there are
 * more options: we may already be running PAE, and the pagetable may
 * or may not be based in swapper_pg_dir.  In any case,
 * paravirt_pagetable_init() will set up swapper_pg_dir
 * appropriately for the rest of the initialization to work.
 *
 * In general, pagetable_init() assumes that the pagetable may already
 * be partially populated, and so it avoids stomping on any existing
 * mappings.
 */
void __init early_ioremap_page_table_range_init(void)
{
    pgd_t *pgd_base = swapper_pg_dir;
    unsigned long vaddr, end;

    /*
     * Fixed mappings, only the page table structure has to be
     * created - mappings will be set by set_fixmap():
     */
    vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
    end = (FIXADDR_TOP + PMD_SIZE - 1) & PMD_MASK;
    page_table_range_init(vaddr, end, pgd_base);
    early_ioremap_reset();
}

static void __init pagetable_init(void)
{
    pgd_t *pgd_base = swapper_pg_dir;

    permanent_kmaps_init(pgd_base);
}

pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
EXPORT_SYMBOL_GPL(__supported_pte_mask);

/* user-defined highmem size */
static unsigned int highmem_pages = -1;

/*
 * highmem=size forces highmem to be exactly 'size' bytes.
 * This works even on boxes that have no highmem otherwise.
 * This also works to reduce highmem size on bigger boxes.
 */
static int __init parse_highmem(char *arg)
{
    if (!arg)
        return -EINVAL;

    highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT;
    return 0;
}
early_param("highmem", parse_highmem);

#define MSG_HIGHMEM_TOO_BIG \
    "highmem size (%luMB) is bigger than pages available (%luMB)!\n"

#define MSG_LOWMEM_TOO_SMALL \
    "highmem size (%luMB) results in <64MB lowmem, ignoring it!\n"
/*
 * All of RAM fits into lowmem - but if user wants highmem
 * artificially via the highmem=x boot parameter then create
 * it:
 */
void __init lowmem_pfn_init(void)
{
    /* max_low_pfn is 0, we already have early_res support */
    max_low_pfn = max_pfn;

    if (highmem_pages == -1)
        highmem_pages = 0;
#ifdef CONFIG_HIGHMEM
    if (highmem_pages >= max_pfn) {
        printk(KERN_ERR MSG_HIGHMEM_TOO_BIG,
            pages_to_mb(highmem_pages), pages_to_mb(max_pfn));
        highmem_pages = 0;
    }
    if (highmem_pages) {
        if (max_low_pfn - highmem_pages < 64*1024*1024/PAGE_SIZE) {
            printk(KERN_ERR MSG_LOWMEM_TOO_SMALL,
                pages_to_mb(highmem_pages));
            highmem_pages = 0;
        }
        max_low_pfn -= highmem_pages;
    }
#else
    if (highmem_pages)
        printk(KERN_ERR "ignoring highmem size on non-highmem kernel!\n");
#endif
}

#define MSG_HIGHMEM_TOO_SMALL \
    "only %luMB highmem pages available, ignoring highmem size of %luMB!\n"

#define MSG_HIGHMEM_TRIMMED \
    "Warning: only 4GB will be used. Use a HIGHMEM64G enabled kernel!\n"
/*
 * We have more RAM than fits into lowmem - we try to put it into
 * highmem, also taking the highmem=x boot parameter into account:
 */
void __init highmem_pfn_init(void)
{
    max_low_pfn = MAXMEM_PFN;

    if (highmem_pages == -1)
        highmem_pages = max_pfn - MAXMEM_PFN;

    if (highmem_pages + MAXMEM_PFN < max_pfn)
        max_pfn = MAXMEM_PFN + highmem_pages;

    if (highmem_pages + MAXMEM_PFN > max_pfn) {
        printk(KERN_WARNING MSG_HIGHMEM_TOO_SMALL,
            pages_to_mb(max_pfn - MAXMEM_PFN),
            pages_to_mb(highmem_pages));
        highmem_pages = 0;
    }
#ifndef CONFIG_HIGHMEM
    /* Maximum memory usable is what is directly addressable */
    printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20);
    if (max_pfn > MAX_NONPAE_PFN)
        printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n");
    else
        printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n");
    max_pfn = MAXMEM_PFN;
#else /* !CONFIG_HIGHMEM */
#ifndef CONFIG_HIGHMEM64G
    if (max_pfn > MAX_NONPAE_PFN) {
        max_pfn = MAX_NONPAE_PFN;
        printk(KERN_WARNING MSG_HIGHMEM_TRIMMED);
    }
#endif /* !CONFIG_HIGHMEM64G */
#endif /* !CONFIG_HIGHMEM */
}

/*
 * Determine low and high memory ranges:
 */
void __init find_low_pfn_range(void)
{
    /* it could update max_pfn */

    if (max_pfn <= MAXMEM_PFN)
        lowmem_pfn_init();
    else
        highmem_pfn_init();
}

#ifndef CONFIG_NEED_MULTIPLE_NODES
void __init initmem_init(void)
{
#ifdef CONFIG_HIGHMEM
    highstart_pfn = highend_pfn = max_pfn;
    if (max_pfn > max_low_pfn)
        highstart_pfn = max_low_pfn;
    printk(KERN_NOTICE "%ldMB HIGHMEM available.\n",
        pages_to_mb(highend_pfn - highstart_pfn));
    num_physpages = highend_pfn;
    high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
#else
    num_physpages = max_low_pfn;
    high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
#endif

    memblock_set_node(0, (phys_addr_t)ULLONG_MAX, 0);
    sparse_memory_present_with_active_regions(0);

#ifdef CONFIG_FLATMEM
    max_mapnr = num_physpages;
#endif
    __vmalloc_start_set = true;

    printk(KERN_NOTICE "%ldMB LOWMEM available.\n",
            pages_to_mb(max_low_pfn));

    setup_bootmem_allocator();
}
#endif /* !CONFIG_NEED_MULTIPLE_NODES */

void __init setup_bootmem_allocator(void)
{
    printk(KERN_INFO "  mapped low ram: 0 - %08lx\n",
         max_pfn_mapped<<PAGE_SHIFT);
    printk(KERN_INFO "  low ram: 0 - %08lx\n", max_low_pfn<<PAGE_SHIFT);

    after_bootmem = 1;
}

/*
 * paging_init() sets up the page tables - note that the first 8MB are
 * already mapped by head.S.
 *
 * This routines also unmaps the page at virtual kernel address 0, so
 * that we can trap those pesky NULL-reference errors in the kernel.
 */
void __init paging_init(void)
{
    pagetable_init();

    __flush_tlb_all();

    kmap_init();

    /*
     * NOTE: at this point the bootmem allocator is fully available.
     */
    olpc_dt_build_devicetree();
    sparse_memory_present_with_active_regions(MAX_NUMNODES);
    sparse_init();
    zone_sizes_init();
}

/*
 * Test if the WP bit works in supervisor mode. It isn't supported on 386's
 * and also on some strange 486's. All 586+'s are OK. This used to involve
 * black magic jumps to work around some nasty CPU bugs, but fortunately the
 * switch to using exceptions got rid of all that.
 */
static void __init test_wp_bit(void)
{
    printk(KERN_INFO
  "Checking if this processor honours the WP bit even in supervisor mode...");

    /* Any page-aligned address will do, the test is non-destructive */
    __set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_KERNEL_RO);
    boot_cpu_data.wp_works_ok = do_test_wp_bit();
    clear_fixmap(FIX_WP_TEST);

    if (!boot_cpu_data.wp_works_ok) {
        printk(KERN_CONT "No.\n");
#ifdef CONFIG_X86_WP_WORKS_OK
        panic(
  "This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
#endif
    } else {
        printk(KERN_CONT "Ok.\n");
    }
}

void __init mem_init(void)
{
    int codesize, reservedpages, datasize, initsize;
    int tmp;

    pci_iommu_alloc();

#ifdef CONFIG_FLATMEM
    BUG_ON(!mem_map);
#endif
    /*
     * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to
     * be done before free_all_bootmem(). Memblock use free low memory for
     * temporary data (see find_range_array()) and for this purpose can use
     * pages that was already passed to the buddy allocator, hence marked as
     * not accessible in the page tables when compiled with
     * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not
     * important here.
     */
    set_highmem_pages_init();

    /* this will put all low memory onto the freelists */
    totalram_pages += free_all_bootmem();

    reservedpages = 0;
    for (tmp = 0; tmp < max_low_pfn; tmp++)
        /*
         * Only count reserved RAM pages:
         */
        if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
            reservedpages++;

    codesize =  (unsigned long) &_etext - (unsigned long) &_text;
    datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
    initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;

    printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, "
            "%dk reserved, %dk data, %dk init, %ldk highmem)\n",
        nr_free_pages() << (PAGE_SHIFT-10),
        num_physpages << (PAGE_SHIFT-10),
        codesize >> 10,
        reservedpages << (PAGE_SHIFT-10),
        datasize >> 10,
        initsize >> 10,
        totalhigh_pages << (PAGE_SHIFT-10));

    printk(KERN_INFO "virtual kernel memory layout:\n"
        "    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
#ifdef CONFIG_HIGHMEM
        "    pkmap   : 0x%08lx - 0x%08lx   (%4ld kB)\n"
#endif
        "    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
        "    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
        "      .init : 0x%08lx - 0x%08lx   (%4ld kB)\n"
        "      .data : 0x%08lx - 0x%08lx   (%4ld kB)\n"
        "      .text : 0x%08lx - 0x%08lx   (%4ld kB)\n",
        FIXADDR_START, FIXADDR_TOP,
        (FIXADDR_TOP - FIXADDR_START) >> 10,

#ifdef CONFIG_HIGHMEM
        PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE,
        (LAST_PKMAP*PAGE_SIZE) >> 10,
#endif

        VMALLOC_START, VMALLOC_END,
        (VMALLOC_END - VMALLOC_START) >> 20,

        (unsigned long)__va(0), (unsigned long)high_memory,
        ((unsigned long)high_memory - (unsigned long)__va(0)) >> 20,

        (unsigned long)&__init_begin, (unsigned long)&__init_end,
        ((unsigned long)&__init_end -
         (unsigned long)&__init_begin) >> 10,

        (unsigned long)&_etext, (unsigned long)&_edata,
        ((unsigned long)&_edata - (unsigned long)&_etext) >> 10,

        (unsigned long)&_text, (unsigned long)&_etext,
        ((unsigned long)&_etext - (unsigned long)&_text) >> 10);

    /*
     * Check boundaries twice: Some fundamental inconsistencies can
     * be detected at build time already.
     */
#define __FIXADDR_TOP (-PAGE_SIZE)
#ifdef CONFIG_HIGHMEM
    BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE  > FIXADDR_START);
    BUILD_BUG_ON(VMALLOC_END            > PKMAP_BASE);
#endif
#define high_memory (-128UL << 20)
    BUILD_BUG_ON(VMALLOC_START          >= VMALLOC_END);
#undef high_memory
#undef __FIXADDR_TOP

#ifdef CONFIG_HIGHMEM
    BUG_ON(PKMAP_BASE + LAST_PKMAP*PAGE_SIZE    > FIXADDR_START);
    BUG_ON(VMALLOC_END              > PKMAP_BASE);
#endif
    BUG_ON(VMALLOC_START                >= VMALLOC_END);
    BUG_ON((unsigned long)high_memory       > VMALLOC_START);

    if (boot_cpu_data.wp_works_ok < 0)
        test_wp_bit();
}

#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size)
{
    struct pglist_data *pgdata = NODE_DATA(nid);
    struct zone *zone = pgdata->node_zones + ZONE_HIGHMEM;
    unsigned long start_pfn = start >> PAGE_SHIFT;
    unsigned long nr_pages = size >> PAGE_SHIFT;

    return __add_pages(nid, zone, start_pfn, nr_pages);
}
#endif

/*
 * This function cannot be __init, since exceptions don't work in that
 * section.  Put this after the callers, so that it cannot be inlined.
 */
static noinline int do_test_wp_bit(void)
{
    char tmp_reg;
    int flag;

    __asm__ __volatile__(
        "   movb %0, %1 \n"
        "1: movb %1, %0 \n"
        "   xorl %2, %2 \n"
        "2:         \n"
        _ASM_EXTABLE(1b,2b)
        :"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
         "=q" (tmp_reg),
         "=r" (flag)
        :"2" (1)
        :"memory");

    return flag;
}

#ifdef CONFIG_DEBUG_RODATA
const int rodata_test_data = 0xC3;
EXPORT_SYMBOL_GPL(rodata_test_data);

int kernel_set_to_readonly __read_mostly;

void set_kernel_text_rw(void)
{
    unsigned long start = PFN_ALIGN(_text);
    unsigned long size = PFN_ALIGN(_etext) - start;

    if (!kernel_set_to_readonly)
        return;

    pr_debug("Set kernel text: %lx - %lx for read write\n",
         start, start+size);

    set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
}

void set_kernel_text_ro(void)
{
    unsigned long start = PFN_ALIGN(_text);
    unsigned long size = PFN_ALIGN(_etext) - start;

    if (!kernel_set_to_readonly)
        return;

    pr_debug("Set kernel text: %lx - %lx for read only\n",
         start, start+size);

    set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
}

static void mark_nxdata_nx(void)
{
    /*
     * When this called, init has already been executed and released,
     * so everything past _etext should be NX.
     */
    unsigned long start = PFN_ALIGN(_etext);
    /*
     * This comes from is_kernel_text upper limit. Also HPAGE where used:
     */
    unsigned long size = (((unsigned long)__init_end + HPAGE_SIZE) & HPAGE_MASK) - start;

    if (__supported_pte_mask & _PAGE_NX)
        printk(KERN_INFO "NX-protecting the kernel data: %luk\n", size >> 10);
    set_pages_nx(virt_to_page(start), size >> PAGE_SHIFT);
}

void mark_rodata_ro(void)
{
    unsigned long start = PFN_ALIGN(_text);
    unsigned long size = PFN_ALIGN(_etext) - start;

    set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
    printk(KERN_INFO "Write protecting the kernel text: %luk\n",
        size >> 10);

    kernel_set_to_readonly = 1;

#ifdef CONFIG_CPA_DEBUG
    printk(KERN_INFO "Testing CPA: Reverting %lx-%lx\n",
        start, start+size);
    set_pages_rw(virt_to_page(start), size>>PAGE_SHIFT);

    printk(KERN_INFO "Testing CPA: write protecting again\n");
    set_pages_ro(virt_to_page(start), size>>PAGE_SHIFT);
#endif

    start += size;
    size = (unsigned long)__end_rodata - start;
    set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
    printk(KERN_INFO "Write protecting the kernel read-only data: %luk\n",
        size >> 10);
    rodata_test();

#ifdef CONFIG_CPA_DEBUG
    printk(KERN_INFO "Testing CPA: undo %lx-%lx\n", start, start + size);
    set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);

    printk(KERN_INFO "Testing CPA: write protecting again\n");
    set_pages_ro(virt_to_page(start), size >> PAGE_SHIFT);
#endif
    mark_nxdata_nx();
}
#endif