The additional fields in struct boot_params as a part of 32-bit boot
  protocol of kernel. These should be filled by bootloader or 16-bit
  real-mode setup code of the kernel. References/settings to it mainly
  are in:

    arch/x86/include/uapi/asm/bootparam.h

  Offset	Proto	Name		Meaning
  /Size

  000/040	ALL	screen_info	Text mode or frame buffer information
  				(struct screen_info)
  040/014	ALL	apm_bios_info	APM BIOS information (struct apm_bios_info)

  058/008	ALL	tboot_addr      Physical address of tboot shared page

  060/010	ALL	ist_info	Intel SpeedStep (IST) BIOS support information
  				(struct ist_info)
  080/010	ALL	hd0_info	hd0 disk parameter, OBSOLETE!!
  090/010	ALL	hd1_info	hd1 disk parameter, OBSOLETE!!

  0A0/010	ALL	sys_desc_table	System description table (struct sys_desc_table),
  				OBSOLETE!!

  0B0/010	ALL	olpc_ofw_header	OLPC's OpenFirmware CIF and friends

  0C0/004	ALL	ext_ramdisk_image ramdisk_image high 32bits
  0C4/004	ALL	ext_ramdisk_size  ramdisk_size high 32bits
  0C8/004	ALL	ext_cmd_line_ptr  cmd_line_ptr high 32bits

  140/080	ALL	edid_info	Video mode setup (struct edid_info)
  1C0/020	ALL	efi_info	EFI 32 information (struct efi_info)
  1E0/004	ALL	alk_mem_k	Alternative mem check, in KB
  1E4/004	ALL	scratch		Scratch field for the kernel setup code

  1E8/001	ALL	e820_entries	Number of entries in e820_table (below)

  1E9/001	ALL	eddbuf_entries	Number of entries in eddbuf (below)
  1EA/001	ALL	edd_mbr_sig_buf_entries	Number of entries in edd_mbr_sig_buffer
  				(below)

  1EB/001	ALL     kbd_status      Numlock is enabled
  1EC/001	ALL     secure_boot	Secure boot is enabled in the firmware

  1EF/001	ALL	sentinel	Used to detect broken bootloaders

  290/040	ALL	edd_mbr_sig_buffer EDD MBR signatures

  2D0/A00	ALL	e820_table	E820 memory map table

  				(array of struct e820_entry)

  D00/1EC	ALL	eddbuf		EDD data (array of struct edd_info)