init.c

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/*
 *  S390 version
 *    Copyright IBM Corp. 1999
 *    Author(s): Hartmut Penner ([email protected])
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1995  Linus Torvalds
 */

#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/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/pfn.h>
#include <linux/poison.h>
#include <linux/initrd.h>
#include <linux/export.h>
#include <linux/gfp.h>
#include <asm/processor.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/dma.h>
#include <asm/lowcore.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/ctl_reg.h>

pgd_t swapper_pg_dir[PTRS_PER_PGD] __attribute__((__aligned__(PAGE_SIZE)));

unsigned long empty_zero_page, zero_page_mask;
EXPORT_SYMBOL(empty_zero_page);

static unsigned long __init setup_zero_pages(void)
{
    struct cpuid cpu_id;
    unsigned int order;
    unsigned long size;
    struct page *page;
    int i;

    get_cpu_id(&cpu_id);
    switch (cpu_id.machine) {
    case 0x9672:    /* g5 */
    case 0x2064:    /* z900 */
    case 0x2066:    /* z900 */
    case 0x2084:    /* z990 */
    case 0x2086:    /* z990 */
    case 0x2094:    /* z9-109 */
    case 0x2096:    /* z9-109 */
        order = 0;
        break;
    case 0x2097:    /* z10 */
    case 0x2098:    /* z10 */
    default:
        order = 2;
        break;
    }

    empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
    if (!empty_zero_page)
        panic("Out of memory in setup_zero_pages");

    page = virt_to_page((void *) empty_zero_page);
    split_page(page, order);
    for (i = 1 << order; i > 0; i--) {
        SetPageReserved(page);
        page++;
    }

    size = PAGE_SIZE << order;
    zero_page_mask = (size - 1) & PAGE_MASK;

    return 1UL << order;
}

/*
 * paging_init() sets up the page tables
 */
void __init paging_init(void)
{
    unsigned long max_zone_pfns[MAX_NR_ZONES];
    unsigned long pgd_type, asce_bits;

    init_mm.pgd = swapper_pg_dir;
#ifdef CONFIG_64BIT
    if (VMALLOC_END > (1UL << 42)) {
        asce_bits = _ASCE_TYPE_REGION2 | _ASCE_TABLE_LENGTH;
        pgd_type = _REGION2_ENTRY_EMPTY;
    } else {
        asce_bits = _ASCE_TYPE_REGION3 | _ASCE_TABLE_LENGTH;
        pgd_type = _REGION3_ENTRY_EMPTY;
    }
#else
    asce_bits = _ASCE_TABLE_LENGTH;
    pgd_type = _SEGMENT_ENTRY_EMPTY;
#endif
    S390_lowcore.kernel_asce = (__pa(init_mm.pgd) & PAGE_MASK) | asce_bits;
    clear_table((unsigned long *) init_mm.pgd, pgd_type,
            sizeof(unsigned long)*2048);
    vmem_map_init();

        /* enable virtual mapping in kernel mode */
    __ctl_load(S390_lowcore.kernel_asce, 1, 1);
    __ctl_load(S390_lowcore.kernel_asce, 7, 7);
    __ctl_load(S390_lowcore.kernel_asce, 13, 13);
    arch_local_irq_restore(4UL << (BITS_PER_LONG - 8));

    atomic_set(&init_mm.context.attach_count, 1);

    sparse_memory_present_with_active_regions(MAX_NUMNODES);
    sparse_init();
    memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
    max_zone_pfns[ZONE_DMA] = PFN_DOWN(MAX_DMA_ADDRESS);
    max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
    free_area_init_nodes(max_zone_pfns);
    fault_init();
}

void __init mem_init(void)
{
    unsigned long codesize, reservedpages, datasize, initsize;

        max_mapnr = num_physpages = max_low_pfn;
        high_memory = (void *) __va(max_low_pfn * PAGE_SIZE);

    /* Setup guest page hinting */
    cmma_init();

    /* this will put all low memory onto the freelists */
    totalram_pages += free_all_bootmem();
    totalram_pages -= setup_zero_pages();   /* Setup zeroed pages. */

    reservedpages = 0;

    codesize =  (unsigned long) &_etext - (unsigned long) &_text;
    datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
    initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
        printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, %ldk data, %ldk init)\n",
        nr_free_pages() << (PAGE_SHIFT-10),
                max_mapnr << (PAGE_SHIFT-10),
                codesize >> 10,
                reservedpages << (PAGE_SHIFT-10),
                datasize >>10,
                initsize >> 10);
    printk("Write protected kernel read-only data: %#lx - %#lx\n",
           (unsigned long)&_stext,
           PFN_ALIGN((unsigned long)&_eshared) - 1);
}

#ifdef CONFIG_DEBUG_PAGEALLOC
void kernel_map_pages(struct page *page, int numpages, int enable)
{
    pgd_t *pgd;
    pud_t *pud;
    pmd_t *pmd;
    pte_t *pte;
    unsigned long address;
    int i;

    for (i = 0; i < numpages; i++) {
        address = page_to_phys(page + i);
        pgd = pgd_offset_k(address);
        pud = pud_offset(pgd, address);
        pmd = pmd_offset(pud, address);
        pte = pte_offset_kernel(pmd, address);
        if (!enable) {
            __ptep_ipte(address, pte);
            pte_val(*pte) = _PAGE_TYPE_EMPTY;
            continue;
        }
        *pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW));
        /* Flush cpu write queue. */
        mb();
    }
}
#endif

void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
    unsigned long addr = begin;

    if (begin >= end)
        return;
    for (; addr < end; addr += PAGE_SIZE) {
        ClearPageReserved(virt_to_page(addr));
        init_page_count(virt_to_page(addr));
        memset((void *)(addr & PAGE_MASK), POISON_FREE_INITMEM,
               PAGE_SIZE);
        free_page(addr);
        totalram_pages++;
    }
    printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
}

void free_initmem(void)
{
    free_init_pages("unused kernel memory",
            (unsigned long)&__init_begin,
            (unsigned long)&__init_end);
}

#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
    free_init_pages("initrd memory", start, end);
}
#endif

#ifdef CONFIG_MEMORY_HOTPLUG
int arch_add_memory(int nid, u64 start, u64 size)
{
    unsigned long zone_start_pfn, zone_end_pfn, nr_pages;
    unsigned long start_pfn = PFN_DOWN(start);
    unsigned long size_pages = PFN_DOWN(size);
    struct zone *zone;
    int rc;

    rc = vmem_add_mapping(start, size);
    if (rc)
        return rc;
    for_each_zone(zone) {
        if (zone_idx(zone) != ZONE_MOVABLE) {
            /* Add range within existing zone limits */
            zone_start_pfn = zone->zone_start_pfn;
            zone_end_pfn = zone->zone_start_pfn +
                       zone->spanned_pages;
        } else {
            /* Add remaining range to ZONE_MOVABLE */
            zone_start_pfn = start_pfn;
            zone_end_pfn = start_pfn + size_pages;
        }
        if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn)
            continue;
        nr_pages = (start_pfn + size_pages > zone_end_pfn) ?
               zone_end_pfn - start_pfn : size_pages;
        rc = __add_pages(nid, zone, start_pfn, nr_pages);
        if (rc)
            break;
        start_pfn += nr_pages;
        size_pages -= nr_pages;
        if (!size_pages)
            break;
    }
    if (rc)
        vmem_remove_mapping(start, size);
    return rc;
}
#endif /* CONFIG_MEMORY_HOTPLUG */