xref: /illumos-gate/usr/src/boot/common/mb_header.S (revision 9174bfaa08ca3aa4c0a12e840c4bd4f2570237a0)
1/*
2 * This file and its contents are supplied under the terms of the
3 * Common Development and Distribution License ("CDDL"), version 1.0.
4 * You may only use this file in accordance with the terms of version
5 * 1.0 of the CDDL.
6 *
7 * A full copy of the text of the CDDL should have accompanied this
8 * source.  A copy of the CDDL is also available via the Internet at
9 * http://www.illumos.org/license/CDDL.
10 */
11
12/*
13 * Copyright 2018 Toomas Soome <tsoome@me.com>
14 */
15
16	.file	"mb_header.S"
17
18/*
19 * Provide fake multiboot header to support versioning and partition
20 * start. The fake MB header is used by versioning code located in
21 * usr/src/cmd/boot/common. Since the BIOS bootblock is stored on raw disk,
22 * this fake header is used to store the location of the version info block.
23 * Additionally we use it to store partition start_sector, so we can identify
24 * our root file system partition. Note we are using LBA64 here.
25 */
26
27#define	ASM_FILE
28#include <sys/multiboot.h>
29
30		.globl mb_header, start_sector
31		.text
32
33		.align 4
34mb_header:
35		.long	MULTIBOOT_HEADER_MAGIC
36		.long	MULTIBOOT_AOUT_KLUDGE
37		.long	-(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_AOUT_KLUDGE)
38		.long	0                       /* header_addr */
39		.long	0                       /* load_addr */
40		.long	0                       /* load_end_addr */
41start_sector:	.long	0			/* partition LBA */
42		.long	0
43
44