xref: /OK3568_Linux_fs/kernel/Documentation/x86/zero-page.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun.. SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun
3*4882a593Smuzhiyun=========
4*4882a593SmuzhiyunZero Page
5*4882a593Smuzhiyun=========
6*4882a593SmuzhiyunThe additional fields in struct boot_params as a part of 32-bit boot
7*4882a593Smuzhiyunprotocol of kernel. These should be filled by bootloader or 16-bit
8*4882a593Smuzhiyunreal-mode setup code of the kernel. References/settings to it mainly
9*4882a593Smuzhiyunare in::
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun  arch/x86/include/uapi/asm/bootparam.h
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun===========	=====	=======================	=================================================
14*4882a593SmuzhiyunOffset/Size	Proto	Name			Meaning
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun000/040		ALL	screen_info		Text mode or frame buffer information
17*4882a593Smuzhiyun						(struct screen_info)
18*4882a593Smuzhiyun040/014		ALL	apm_bios_info		APM BIOS information (struct apm_bios_info)
19*4882a593Smuzhiyun058/008		ALL	tboot_addr      	Physical address of tboot shared page
20*4882a593Smuzhiyun060/010		ALL	ist_info		Intel SpeedStep (IST) BIOS support information
21*4882a593Smuzhiyun						(struct ist_info)
22*4882a593Smuzhiyun080/010		ALL	hd0_info		hd0 disk parameter, OBSOLETE!!
23*4882a593Smuzhiyun090/010		ALL	hd1_info		hd1 disk parameter, OBSOLETE!!
24*4882a593Smuzhiyun0A0/010		ALL	sys_desc_table		System description table (struct sys_desc_table),
25*4882a593Smuzhiyun						OBSOLETE!!
26*4882a593Smuzhiyun0B0/010		ALL	olpc_ofw_header		OLPC's OpenFirmware CIF and friends
27*4882a593Smuzhiyun0C0/004		ALL	ext_ramdisk_image	ramdisk_image high 32bits
28*4882a593Smuzhiyun0C4/004		ALL	ext_ramdisk_size	ramdisk_size high 32bits
29*4882a593Smuzhiyun0C8/004		ALL	ext_cmd_line_ptr	cmd_line_ptr high 32bits
30*4882a593Smuzhiyun140/080		ALL	edid_info		Video mode setup (struct edid_info)
31*4882a593Smuzhiyun1C0/020		ALL	efi_info		EFI 32 information (struct efi_info)
32*4882a593Smuzhiyun1E0/004		ALL	alt_mem_k		Alternative mem check, in KB
33*4882a593Smuzhiyun1E4/004		ALL	scratch			Scratch field for the kernel setup code
34*4882a593Smuzhiyun1E8/001		ALL	e820_entries		Number of entries in e820_table (below)
35*4882a593Smuzhiyun1E9/001		ALL	eddbuf_entries		Number of entries in eddbuf (below)
36*4882a593Smuzhiyun1EA/001		ALL	edd_mbr_sig_buf_entries	Number of entries in edd_mbr_sig_buffer
37*4882a593Smuzhiyun						(below)
38*4882a593Smuzhiyun1EB/001		ALL     kbd_status      	Numlock is enabled
39*4882a593Smuzhiyun1EC/001		ALL     secure_boot		Secure boot is enabled in the firmware
40*4882a593Smuzhiyun1EF/001		ALL	sentinel		Used to detect broken bootloaders
41*4882a593Smuzhiyun290/040		ALL	edd_mbr_sig_buffer	EDD MBR signatures
42*4882a593Smuzhiyun2D0/A00		ALL	e820_table		E820 memory map table
43*4882a593Smuzhiyun						(array of struct e820_entry)
44*4882a593SmuzhiyunD00/1EC		ALL	eddbuf			EDD data (array of struct edd_info)
45*4882a593Smuzhiyun===========	=====	=======================	=================================================
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