/*

   *  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 <linux/memblock.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/trampoline.h>

  #include <asm/bios_ebda.h>

  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();

  	max_pfn_mapped = KERNEL_IMAGE_SIZE >> PAGE_SHIFT;

  	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
  ");

  	x86_64_start_reservations(real_mode_data);
  }
  
  void __init x86_64_start_reservations(char *real_mode_data)
  {

  	copy_bootdata(__va(real_mode_data));

  	memblock_reserve(__pa_symbol(&_text),
  			 __pa_symbol(&__bss_stop) - __pa_symbol(&_text));

  #ifdef CONFIG_BLK_DEV_INITRD

  	/* Reserve INITRD */
  	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {

  		/* Assume only end is not page aligned */

  		unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
  		unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;

  		unsigned long ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);

  		memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);

  	}

  #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();
  }