linux/arch/x86/kernel/head64.c
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   1/*
   2 *  prepare to run common code
   3 *
   4 *  Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
   5 */
   6
   7#include <linux/init.h>
   8#include <linux/linkage.h>
   9#include <linux/types.h>
  10#include <linux/kernel.h>
  11#include <linux/string.h>
  12#include <linux/percpu.h>
  13#include <linux/start_kernel.h>
  14#include <linux/io.h>
  15
  16#include <asm/processor.h>
  17#include <asm/proto.h>
  18#include <asm/smp.h>
  19#include <asm/setup.h>
  20#include <asm/desc.h>
  21#include <asm/pgtable.h>
  22#include <asm/tlbflush.h>
  23#include <asm/sections.h>
  24#include <asm/kdebug.h>
  25#include <asm/e820.h>
  26#include <asm/bios_ebda.h>
  27#include <asm/trampoline.h>
  28
  29static void __init zap_identity_mappings(void)
  30{
  31        pgd_t *pgd = pgd_offset_k(0UL);
  32        pgd_clear(pgd);
  33        __flush_tlb_all();
  34}
  35
  36/* Don't add a printk in there. printk relies on the PDA which is not initialized 
  37   yet. */
  38static void __init clear_bss(void)
  39{
  40        memset(__bss_start, 0,
  41               (unsigned long) __bss_stop - (unsigned long) __bss_start);
  42}
  43
  44static void __init copy_bootdata(char *real_mode_data)
  45{
  46        char * command_line;
  47
  48        memcpy(&boot_params, real_mode_data, sizeof boot_params);
  49        if (boot_params.hdr.cmd_line_ptr) {
  50                command_line = __va(boot_params.hdr.cmd_line_ptr);
  51                memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
  52        }
  53}
  54
  55void __init x86_64_start_kernel(char * real_mode_data)
  56{
  57        int i;
  58
  59        /*
  60         * Build-time sanity checks on the kernel image and module
  61         * area mappings. (these are purely build-time and produce no code)
  62         */
  63        BUILD_BUG_ON(MODULES_VADDR < KERNEL_IMAGE_START);
  64        BUILD_BUG_ON(MODULES_VADDR-KERNEL_IMAGE_START < KERNEL_IMAGE_SIZE);
  65        BUILD_BUG_ON(MODULES_LEN + KERNEL_IMAGE_SIZE > 2*PUD_SIZE);
  66        BUILD_BUG_ON((KERNEL_IMAGE_START & ~PMD_MASK) != 0);
  67        BUILD_BUG_ON((MODULES_VADDR & ~PMD_MASK) != 0);
  68        BUILD_BUG_ON(!(MODULES_VADDR > __START_KERNEL));
  69        BUILD_BUG_ON(!(((MODULES_END - 1) & PGDIR_MASK) ==
  70                                (__START_KERNEL & PGDIR_MASK)));
  71        BUILD_BUG_ON(__fix_to_virt(__end_of_fixed_addresses) <= MODULES_END);
  72
  73        /* clear bss before set_intr_gate with early_idt_handler */
  74        clear_bss();
  75
  76        /* Make NULL pointers segfault */
  77        zap_identity_mappings();
  78
  79        /* Cleanup the over mapped high alias */
  80        cleanup_highmap();
  81
  82        for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
  83#ifdef CONFIG_EARLY_PRINTK
  84                set_intr_gate(i, &early_idt_handlers[i]);
  85#else
  86                set_intr_gate(i, early_idt_handler);
  87#endif
  88        }
  89        load_idt((const struct desc_ptr *)&idt_descr);
  90
  91        if (console_loglevel == 10)
  92                early_printk("Kernel alive\n");
  93
  94        x86_64_start_reservations(real_mode_data);
  95}
  96
  97void __init x86_64_start_reservations(char *real_mode_data)
  98{
  99        copy_bootdata(__va(real_mode_data));
 100
 101        reserve_trampoline_memory();
 102
 103        reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");
 104
 105#ifdef CONFIG_BLK_DEV_INITRD
 106        /* Reserve INITRD */
 107        if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
 108                unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
 109                unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
 110                unsigned long ramdisk_end   = ramdisk_image + ramdisk_size;
 111                reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
 112        }
 113#endif
 114
 115        reserve_ebda_region();
 116
 117        /*
 118         * At this point everything still needed from the boot loader
 119         * or BIOS or kernel text should be early reserved or marked not
 120         * RAM in e820. All other memory is free game.
 121         */
 122
 123        start_kernel();
 124}
 125
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