Linux XBE Bootloader
~~~~~~~~~~~~~~~~~~~~
Usage:
The "New" Xbeboot has a nice now very cool feature
It supports Linking of the
vmlinuz
initrd
linuxboot.cfg
into the .xbe file
So, your compleate Linux shrinks down to a single file, which holds everything in it.
There are some "limits"
The Kernel Size is limited to 1MB
The RAMdisk is unknown, i tested with a 12MB ramdisk here, and it worked.
so, how to do this now.
METHOD 1:
If you want the conventional Method:
Go to the config.h file
and do
#define LOADHDD
#undef LOADXBE
This will force the Xbeboot to load all 3 files now from the HDD
In this mode, you can choose a config fallback
#define LOADHDD_CFGFALLBACK
means:
if the Xbeboot can not load the linuxboot.cfg from the hdd,
it will try to take the one linked into the xbeboot
METHOD 2:
Ok, now the New method
#define LOADXBE
#undef LOADHDD
This now tells the XBEBOOT only to take the 3 Files from the XBEBOOT
even if the files are existing on the hdd, it will not take care of them
This provides a single standalone Soulution for small Linux Distros and so.
Ok, now the question:
Where does it get the kernel from ?
Only place the 3 files
vmlinuz
initrd
linuxboot.cfg
into the xbeboot directory
This is all.
Happy hacking..
franz & ed
(C)2002 by Michael Steil <mist@c64.org>,
based on code by M. Steil & Anonymous
Linux VESA Framebuffer support by Milosch Meriac <xboxlinux@meriac.de>
No-Initrd-Fix by Edgar Hucek <hostmaster@ed-soft.at>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Features
~~~~~~~~~
The Linux XBE Bootloader is an Xbox XBE file that boots the Linux kernel.
It supports configuration files, standard i386 bzImage kernels (no zImage)
initial RAM disks, and a kernel command line.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Location of the Configuration File
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The bootloader executable can be started from hard disk or CD/DVD. It first
reads the file "linuxboot.cfg" from the same directory on hard disk or CD/DVD
the bootloader executable resides in.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Configuration File Commands
~~~~~~~~~~~~~~~~~~~~~~~~~~~
The configuration file is a plaintext file containing one or more lines each
with a command, and, sepatated with a space or tab, the command's parameters.
The bootloader knows the following commands (note that the case of the commands
does not matter):
{TITLE|LABEL}
~~~~~~~~~~~~~
Reserved keywords. Will be important for multiple configurations.
Example:
TITLE linux
ROOT
~~~~
NT namespace base path. This path will be prepended to the paths of the
kernel image and the initial RAM disk.
If you don't set the root directory, it is set to the directory of the
bootloader executable by default.
Examples:
ROOT \Device\Harddisk0\Partition1 (the system partition)
ROOT \Device\CdRom0 (the CD/DVD)
ROOT \??\D: (also the CD/DVD)
KERNEL
~~~~~~
Relative path and filename of the kernel image. Optionally, you can supply
a kernel command line after the kernel path and filename. The parameter
"initrd=" gets recognized as the initial RAM disk filename (see below); this
parameter won't be passed to the kernel.
Examples:
KERNEL data\vmlinuz
KERNEL vmlinuz
KERNEL \vmlinuz (the same as "vmlinuz")
KERNEL \vmlinuz-2.4.18 root=/dev/hda1 initrd=\initrd-2.4.18.gz
INITRD
~~~~~~
Relative path and filename of the initial ramdisk. An Initrd is optional.
Examples:
INITRD boot\initrd-failsafe.gz
INITRD initrd.gz
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Note that the syntax of the configuration file is very similar to GRUB's and
SYSLINUX'. You have two possibilities to pass the bootloader the path
and filename of the configuartion file, one is "the GRUB way" and the other
one is "the SYSLINUX way". There are also two ways to pass the kernel command
line.
If the same command is read multiple times, only the last one is preserved
for ROOT, KERNEL and INITRD. For the kernel command line, all command line
parts defined using the different commands are concatenated.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The Kernel Command Line
~~~~~~~~~~~~~~~~~~~~~~~
The bootloader automatically adds the following parameters to the kernel
command line:
xboxeepromkey=00112233445566778899AABBCCDDEEFF
xboxhdkey=00112233445566778899AABBCCDDEEFF
so that applications can access these resources without them having to be
included or caculated (legal problems). Note however that the EEPROMKey might
not be available when booting from the Dashboard or another utility application.
The parameter:
kbd-reset
is also passed to the kernel to make it detect that there is no keyboard
controller.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The NT Object Namespace
~~~~~~~~~~~~~~~~~~~~~~~
All paths and filenames are passed to the Xbox kernel, so you have to use the
NT object namespace for the "root" path. Here is a short table with all drives
known to the Xbox kernel.
Symbolic Link Device Object Description
~~~~~~~~~~~~ ~~~~~~~~~~~~~ ~~~~~~~~~~~
\??\C: \Device\Harddisk0\Partition2 System Partition (500 MB)
\??\D: \Device\CdRom0 CD/DVD
\??\E: \Device\Harddisk0\Partition1 Data Partition (4895 GB)
\??\F: \Device\Harddisk0\Partition6 EvoX Additional Partition
\??\X: \Device\Harddisk0\Partition3 Game Cache A (750 MB)
\??\Y: \Device\Harddisk0\Partition4 Game Cache B (750 MB)
\??\Z: \Device\Harddisk0\Partition5 Game Cache C (750 MB)
The subdirectory and the filename are added to the volume base, so that
for example \Device\Harddisk0\Partition2\Linux\vmlinuz and \\??\D:\vmlinuz
are both valid absolute paths. Note that all subdirectory and file names
are case insensitive. Also note that some utility applications such as
EvoX might redefine some symbolic links, only the device object paths are
static.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Example Configuration Files
~~~~~~~~~~~~~~~~~~~~~~~~~~~
# GRUB style
root \Device\Hardisk0\Partion1\Linux
kernel vmlinuz hdb=ide-scsi root=/dev/hda1
initrd initrd
# SYSLINUX style
kernel \Device\Hardisk0\Partion1\Linux\vmlinuz
append initrd=\Device\Hardisk0\Partion1\Linux\initrd hdb=ide-scsi
append root=/dev/hda1
# minimal, all files in the directory of the bootloader
kernel vmlinuz initrd=initrd root=/dev/hda1
# minimal #2, no initrd
kernel vmlinuz root=/dev/hda1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Video Resolution
~~~~~~~~~~~~~~~~
The bootloader detects whether the Xbox is in 640x480 or 640x576 (PAL box
with Linux booted from the Dashboard) mode and tells Linux the resolution.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
TODO
~~~~
* Xbox kernel calls should be abstracted to fopen/fread/fclose.
* header.S is stille quite a mess
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~