init.c

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/*
 * Copyright (C) 2004-2006 Atmel Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/init.h>
#include <linux/mmzone.h>
#include <linux/module.h>
#include <linux/bootmem.h>
#include <linux/pagemap.h>
#include <linux/nodemask.h>

#include <asm/page.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/setup.h>
#include <asm/sections.h>

pgd_t swapper_pg_dir[PTRS_PER_PGD] __page_aligned_data;

struct page *empty_zero_page;
EXPORT_SYMBOL(empty_zero_page);

/*
 * Cache of MMU context last used.
 */
unsigned long mmu_context_cache = NO_CONTEXT;

/*
 * paging_init() sets up the page tables
 *
 * This routine 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)
{
    extern unsigned long _evba;
    void *zero_page;
    int nid;

    /*
     * Make sure we can handle exceptions before enabling
     * paging. Not that we should ever _get_ any exceptions this
     * early, but you never know...
     */
    printk("Exception vectors start at %p\n", &_evba);
    sysreg_write(EVBA, (unsigned long)&_evba);

    /*
     * Since we are ready to handle exceptions now, we should let
     * the CPU generate them...
     */
    __asm__ __volatile__ ("csrf %0" : : "i"(SR_EM_BIT));

    /*
     * Allocate the zero page. The allocator will panic if it
     * can't satisfy the request, so no need to check.
     */
    zero_page = alloc_bootmem_low_pages_node(NODE_DATA(0),
                         PAGE_SIZE);

    sysreg_write(PTBR, (unsigned long)swapper_pg_dir);
    enable_mmu();
    printk ("CPU: Paging enabled\n");

    for_each_online_node(nid) {
        pg_data_t *pgdat = NODE_DATA(nid);
        unsigned long zones_size[MAX_NR_ZONES];
        unsigned long low, start_pfn;

        start_pfn = pgdat->bdata->node_min_pfn;
        low = pgdat->bdata->node_low_pfn;

        memset(zones_size, 0, sizeof(zones_size));
        zones_size[ZONE_NORMAL] = low - start_pfn;

        printk("Node %u: start_pfn = 0x%lx, low = 0x%lx\n",
               nid, start_pfn, low);

        free_area_init_node(nid, zones_size, start_pfn, NULL);

        printk("Node %u: mem_map starts at %p\n",
               pgdat->node_id, pgdat->node_mem_map);
    }

    mem_map = NODE_DATA(0)->node_mem_map;

    empty_zero_page = virt_to_page(zero_page);
    flush_dcache_page(empty_zero_page);
}

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

    reservedpages = 0;
    high_memory = NULL;

    /* this will put all low memory onto the freelists */
    for_each_online_node(nid) {
        pg_data_t *pgdat = NODE_DATA(nid);
        unsigned long node_pages = 0;
        void *node_high_memory;

        num_physpages += pgdat->node_present_pages;

        if (pgdat->node_spanned_pages != 0)
            node_pages = free_all_bootmem_node(pgdat);

        totalram_pages += node_pages;

        for (i = 0; i < node_pages; i++)
            if (PageReserved(pgdat->node_mem_map + i))
                reservedpages++;

        node_high_memory = (void *)((pgdat->node_start_pfn
                         + pgdat->node_spanned_pages)
                        << PAGE_SHIFT);
        if (node_high_memory > high_memory)
            high_memory = node_high_memory;
    }

    max_mapnr = MAP_NR(high_memory);

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

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

static inline void free_area(unsigned long addr, unsigned long end, char *s)
{
    unsigned int size = (end - addr) >> 10;

    for (; addr < end; addr += PAGE_SIZE) {
        struct page *page = virt_to_page(addr);
        ClearPageReserved(page);
        init_page_count(page);
        free_page(addr);
        totalram_pages++;
    }

    if (size && s)
        printk(KERN_INFO "Freeing %s memory: %dK (%lx - %lx)\n",
               s, size, end - (size << 10), end);
}

void free_initmem(void)
{
    free_area((unsigned long)__init_begin, (unsigned long)__init_end,
          "init");
}

#ifdef CONFIG_BLK_DEV_INITRD

void free_initrd_mem(unsigned long start, unsigned long end)
{
    free_area(start, end, "initrd");
}

#endif