usr/src/boot/common/mb_header.S

root/usr/src/boot/common/mb_header.S
/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2018 Toomas Soome <tsoome@me.com>
 */

        .file   "mb_header.S"

/*
 * Provide fake multiboot header to support versioning and partition
 * start. The fake MB header is used by versioning code located in
 * usr/src/cmd/boot/common. Since the BIOS bootblock is stored on raw disk,
 * this fake header is used to store the location of the version info block.
 * Additionally we use it to store partition start_sector, so we can identify
 * our root file system partition. Note we are using LBA64 here.
 */

#define ASM_FILE
#include <sys/multiboot.h>

                .globl mb_header, start_sector
                .text

                .align 4
mb_header:
                .long   MULTIBOOT_HEADER_MAGIC
                .long   MULTIBOOT_AOUT_KLUDGE
                .long   -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_AOUT_KLUDGE)
                .long   0                       /* header_addr */
                .long   0                       /* load_addr */
                .long   0                       /* load_end_addr */
start_sector:   .long   0                       /* partition LBA */
                .long   0
Illumos
