10. Zero PageΒΆ
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)  |