1.. SPDX-License-Identifier: GPL-2.0 2 3========= 4Zero Page 5========= 6The additional fields in struct boot_params as a part of 32-bit boot 7protocol of kernel. These should be filled by bootloader or 16-bit 8real-mode setup code of the kernel. References/settings to it mainly 9are in:: 10 11 arch/x86/include/uapi/asm/bootparam.h 12 13=========== ===== ======================= ================================================= 14Offset/Size Proto Name Meaning 15 16000/040 ALL screen_info Text mode or frame buffer information 17 (struct screen_info) 18040/014 ALL apm_bios_info APM BIOS information (struct apm_bios_info) 19058/008 ALL tboot_addr Physical address of tboot shared page 20060/010 ALL ist_info Intel SpeedStep (IST) BIOS support information 21 (struct ist_info) 22080/010 ALL hd0_info hd0 disk parameter, OBSOLETE!! 23090/010 ALL hd1_info hd1 disk parameter, OBSOLETE!! 240A0/010 ALL sys_desc_table System description table (struct sys_desc_table), 25 OBSOLETE!! 260B0/010 ALL olpc_ofw_header OLPC's OpenFirmware CIF and friends 270C0/004 ALL ext_ramdisk_image ramdisk_image high 32bits 280C4/004 ALL ext_ramdisk_size ramdisk_size high 32bits 290C8/004 ALL ext_cmd_line_ptr cmd_line_ptr high 32bits 30140/080 ALL edid_info Video mode setup (struct edid_info) 311C0/020 ALL efi_info EFI 32 information (struct efi_info) 321E0/004 ALL alt_mem_k Alternative mem check, in KB 331E4/004 ALL scratch Scratch field for the kernel setup code 341E8/001 ALL e820_entries Number of entries in e820_table (below) 351E9/001 ALL eddbuf_entries Number of entries in eddbuf (below) 361EA/001 ALL edd_mbr_sig_buf_entries Number of entries in edd_mbr_sig_buffer 37 (below) 381EB/001 ALL kbd_status Numlock is enabled 391EC/001 ALL secure_boot Secure boot is enabled in the firmware 401EF/001 ALL sentinel Used to detect broken bootloaders 41290/040 ALL edd_mbr_sig_buffer EDD MBR signatures 422D0/A00 ALL e820_table E820 memory map table 43 (array of struct e820_entry) 44D00/1EC ALL eddbuf EDD data (array of struct edd_info) 45=========== ===== ======================= ================================================= 46