freebsd-dev/sys/boot/i386/common/bootargs.h
Andriy Gapon 29c8c4b0f5 btxldr: future-proof argument passing from boot1/2-ish to loader
Place the arguments at a fixed offset of 0x800 withing the argument area
(of size 0x1000).  Allow variable size extended arguments first of which
should be a size of the extended arguments (including the size
parameter).

Consolidate all related definitions in a new i386/common/bootargs.h header.

Many thanks to jhb and bde for their guidance and reviews.

Reviewed by:	jhb, bde
Approved by:	jhb
MFC after:	1 month
2012-05-09 08:04:29 +00:00

70 lines
2.1 KiB
C

/*-
* Copyright (c) 2012 Andriy Gapon <avg@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms are freely
* permitted provided that the above copyright notice and this
* paragraph and the following disclaimer are duplicated in all
* such forms.
*
* This software is provided "AS IS" and without any express or
* implied warranties, including, without limitation, the implied
* warranties of merchantability and fitness for a particular
* purpose.
*
* $FreeBSD$
*/
#ifndef _BOOT_I386_ARGS_H_
#define _BOOT_I386_ARGS_H_
#define KARGS_FLAGS_CD 0x1
#define KARGS_FLAGS_PXE 0x2
#define KARGS_FLAGS_ZFS 0x4
#define KARGS_FLAGS_EXTARG 0x8 /* variably sized extended argument */
#define BOOTARGS_SIZE 24 /* sizeof(struct bootargs) */
#define BA_BOOTFLAGS 8 /* offsetof(struct bootargs, bootflags) */
#define BA_BOOTINFO 20 /* offsetof(struct bootargs, bootinfo) */
#define BI_SIZE 48 /* offsetof(struct bootinfo, bi_size) */
/*
* We reserve some space above BTX allocated stack for the arguments
* and certain data that could hang off them. Currently only struct bootinfo
* is supported in that category. The bootinfo is placed at the top
* of the arguments area and the actual arguments are placed at ARGOFF offset
* from the top and grow towards the top. Hopefully we have enough space
* for bootinfo and the arguments to not run into each other.
* Arguments area below ARGOFF is reserved for future use.
*/
#define ARGSPACE 0x1000 /* total size of the BTX args area */
#define ARGOFF 0x800 /* actual args offset within the args area */
#define ARGADJ (ARGSPACE - ARGOFF)
#ifndef __ASSEMBLER__
struct bootargs
{
uint32_t howto;
uint32_t bootdev;
uint32_t bootflags;
union {
struct {
uint32_t pxeinfo;
uint32_t reserved;
};
uint64_t zfspool;
};
uint32_t bootinfo;
/*
* If KARGS_FLAGS_EXTARG is set in bootflags, then the above fields
* are followed by a uint32_t field that specifies a size of the
* extended arguments (including the size field).
*/
};
#endif /*__ASSEMBLER__*/
#endif /* !_BOOT_I386_ARGS_H_ */