The additional fields in struct boot_params as a part of 32-bit bootprotocol of kernel. These should be filled by bootloader or 16-bitreal-mode setup code of the kernel. References/settings to it mainlyare in: arch/x86/include/asm/bootparam.hOffset Proto Name Meaning/Size000/040 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 page060/010 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)0B0/010 ALL olpc_ofw_header OLPC's OpenFirmware CIF and friends0C0/004 ALL ext_ramdisk_image ramdisk_image high 32bits0C4/004 ALL ext_ramdisk_size ramdisk_size high 32bits0C8/004 ALL ext_cmd_line_ptr cmd_line_ptr high 32bits140/080 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 KB1E4/004 ALL scratch Scratch field for the kernel setup code1E8/001 ALL e820_entries Number of entries in e820_map (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)1EF/001 ALL sentinel Used to detect broken bootloaders290/040 ALL edd_mbr_sig_buffer EDD MBR signatures2D0/A00 ALL e820_map E820 memory map table (array of struct e820entry)D00/1EC ALL eddbuf EDD data (array of struct edd_info)
