root/arch/x86/kernel/head64.c

DEFINITIONS

1. x86_64_init_pda
2. zap_identity_mappings
3. clear_bss
4. copy_bootdata
5. x86_64_start_kernel
6. x86_64_start_reservations

/*
 *  prepare to run common code
 *
 *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
 */

#include <linux/init.h>
#include <linux/linkage.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/percpu.h>
#include <linux/start_kernel.h>
#include <linux/io.h>

#include <asm/processor.h>
#include <asm/proto.h>
#include <asm/smp.h>
#include <asm/setup.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/kdebug.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>

/* boot cpu pda */
static struct x8664_pda _boot_cpu_pda __read_mostly;

#ifdef CONFIG_SMP
/*
 * We install an empty cpu_pda pointer table to indicate to early users
 * (numa_set_node) that the cpu_pda pointer table for cpus other than
 * the boot cpu is not yet setup.
 */
static struct x8664_pda *__cpu_pda[NR_CPUS] __initdata;
#else
static struct x8664_pda *__cpu_pda[NR_CPUS] __read_mostly;
#endif

void __init x86_64_init_pda(void)
{
        _cpu_pda = __cpu_pda;
        cpu_pda(0) = &_boot_cpu_pda;
        pda_init(0);
}

static void __init zap_identity_mappings(void)
{
        pgd_t *pgd = pgd_offset_k(0UL);
        pgd_clear(pgd);
        __flush_tlb_all();
}

/* Don't add a printk in there. printk relies on the PDA which is not initialized 
   yet. */
static void __init clear_bss(void)
{
        memset(__bss_start, 0,
               (unsigned long) __bss_stop - (unsigned long) __bss_start);
}

static void __init copy_bootdata(char *real_mode_data)
{
        char * command_line;

        memcpy(&boot_params, real_mode_data, sizeof boot_params);
        if (boot_params.hdr.cmd_line_ptr) {
                command_line = __va(boot_params.hdr.cmd_line_ptr);
                memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
        }
}

void __init x86_64_start_kernel(char * real_mode_data)
{
        int i;

        /*
         * Build-time sanity checks on the kernel image and module
         * area mappings. (these are purely build-time and produce no code)
         */
        BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
        BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
        BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
        BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
        BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
        BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
        BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
                                (__START_KERNEL & PGDIR_MASK)));
        BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);

        /* clear bss before set_intr_gate with early_idt_handler */
        clear_bss();

        /* Make NULL pointers segfault */
        zap_identity_mappings();

        /* Cleanup the over mapped high alias */
        cleanup_highmap();

        for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
#ifdef CONFIG_EARLY_PRINTK
                set_intr_gate(i, &early_idt_handlers[i]);
#else
                set_intr_gate(i, early_idt_handler);
#endif
        }
        load_idt((const struct desc_ptr *)&idt_descr);

        if (console_loglevel == 10)
                early_printk("Kernel alive\n");

        x86_64_init_pda();

        x86_64_start_reservations(real_mode_data);
}

void __init x86_64_start_reservations(char *real_mode_data)
{
        copy_bootdata(__va(real_mode_data));

        reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");

#ifdef CONFIG_BLK_DEV_INITRD
        /* Reserve INITRD */
        if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
                unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
                unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
                unsigned long ramdisk_end   = ramdisk_image + ramdisk_size;
                reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
        }
#endif

        reserve_ebda_region();

        /*
         * At this point everything still needed from the boot loader
         * or BIOS or kernel text should be early reserved or marked not
         * RAM in e820. All other memory is free game.
         */

        start_kernel();
}