.. SPDX-License-Identifier: GPL-2.0 ========= Zero Page ========= 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/Size Proto Name Meaning 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) 070/008 ALL acpi_rsdp_addr Physical address of ACPI RSDP table 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 13C/004 ALL cc_blob_address Physical address of Confidential Computing blob 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 alt_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) =========== ===== ======================= =================================================