SGI O2/Linux HOWTO

Linux/O2 HOWTO

Author: Steven Seeger <sseeger@stellartec.com>
Edited by: Ilya Volynets <ilya@theIlya.com>

July 24, 2002
Dec 26, 2003

This FAQ describes booting the SGI O2 over the network from a server PC
running dhcpd, and mounting an NFS root filesystem from that PC. This
document will be covered in two steps: the O2 setup, and the PC setup.

1. Copyright

Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with the
Invariant Sections being Copyright, with no Front-Cover Texts and with
no Back-Cover Texts.

A copy of the GNU Free Documentation License is available on the
World Wide Web at http://www.gnu.org/copyleft/fdl.html You can also
obtain it by writing to the

Free Software Foundation, Inc.
59 Temple Place - Suite 330
Boston, MA 02111-1307
USA

2. Linux/MIPS net resources.

2.1 General Resources
linux-mips.org has most of Linux/MIPS related info as of today
glaurung (Vivien Chappelier) has lot of O2-related stuff, including precompiled kernels.
Total Knowledge also has some interesting info (including this file)
irc://irc.freenode.net/#mipslinux is a place where many of Linux/MIPS
developers hang out

2.2 Obtaining O2 Kernel
Please see Linux/MIPS HOWTO for information on obtaining the latest
Linux/MIPS kernel sources. It also contains anonymous CVS and FTP info.
As of this writing, plain LMO kernel doesn't work. You will need some patches to even
make O2 sources boot (and maybe even compile).
Minimal, but most up-to-date set of patches can be found at
http://www.total-knowledge.com/progs/mips/patches/.
For more comprehensive, but less up-to-date set, see Vivien's page mentioned above.

3. Setting up the PC

The PC will need to run tftpd, dhcpd (or a standalone bootpd), and NFS
mountd. You can connect the O2 and the PC together with a crossover
cable, or you can connect the O2 to your network. My computer is a PC
based Linux box running RedHat 7.2, and all examples that follow will
relate to RH 7.2 and xinetd.

3.1 dhcpd

The dhcpd service is used to respond to the bootp protocol that the O2
will want to use for booting. In my situation, I have the O2 on my
network but also have a router that connects the whole house and provides
DHCP for it. The example dhcpd.conf file has IP address leasing disabled.
Setting the O2's IP is described in detail in the next section.

The dhcpd RPM that is floating around as of this writing for RedHat 7.2
does not seem to work with the O2. Upgrading to the latest version of
dhcpd from ISC seemed to fix my problem. The example
/etc/dhcpd.conf file below shows my situation here at home where my
house is networked on a 192.168.1.0 network with a 255.255.255.0 subnet.
My O2 is set to 192.168.1.10.

3.1.1 Example dhcpd.conf

# dhcpd.conf
#
# Sample configuration file for ISC dhcpd
#

# option definitions common to all supported networks...

#the following line is required for dhcpd version 3.0p1
ddns-update-style ad-hoc;

option subnet-mask 255.255.255.0;
default-lease-time 0;
max-lease-time 0;
subnet 192.168.1.0 netmask 255.255.255.0 {
#nothing in here...no ip leasing
}

# Fixed IP addresses can also be specified for hosts. These addresses
# should not also be listed as being available for dynamic assignment.
# Hosts for which fixed IP addresses have been specified can boot using
# BOOTP or DHCP. Hosts for which no fixed address is specified can only
# be booted with DHCP, unless there is an address range on the subnet
# to which a BOOTP client is connected which has the dynamic-bootp flag
# set.

#the O2 goes here. I gave mine the IP 192.168.1.10
#use printenv in the O2's command monitor and look at eaddr for the
#hardware eth id

host sgio2 {
hardware ethernet 08:00:69:0c:79:db;
fixed-address 192.168.1.10;
filename "vmlinux";
}

3.1.2 tftpd, xinetd, and portmap

In the example dhcpd.conf file above, notice the filename="vmlinux" line.
That line tells the O2 what filename to get from your tftpd. The current
RPM for RedHat 7.2 tftp works fine for my O2 and can be found on
rpmfind.net if you don't have it. This version for RH runs under
xinetd and xinetd must be enabled along with portmapper for it to work.
(You can run serviceconf in X to configure these services.)

There is no configuration needed for tftpd. Just install the rpm and
start the service in serviceconf along with portmap and xinetd. At a
prompt type "service xinetd restart" and it will begin running. By
default, tftpd wants to service a directory on /tftpboot.

The "vmlinux" file will go in that /tftpboot directory. If you have no
"vmlinux" file suitable for booting your O2, then scroll up and click
on that link to oss.sgi.com. :)

In order for portmap to function properly, the following lines should
be added to your /etc/hosts.allow file:

portmap:ALL
tftpd:ALL

If you don't want to give access to all IP addresses, then you can
replace ALL with whatever is suitable as well as use wildcards
(ex 192.168.1.*)

In order to be sure that your tftpd works properly, you can test it
with your tftp client. Connect to localhost and try to get a file from
your /tftpboot directory. If that works, then you're almost good to go.

If your O2 doesn't seem able to connect to the tftpd, then add the
following line to your /etc/sysctl.conf file:

net.ipv4.ip_no_pmtu_disc = 1

or type at a prompt:

echo 1 > /proc/sys/net/ipv4/ip_no_pmtu_disc

3.1.3 NFS and mountd

In order to mount a root fs from your O2, you need to set up mountd.
The nfs service should be started in serviceconf. The following line
should be added to /etc/hosts.allow:

mountd:ALL

In /etc/exports, add:

/pathname/rootfsdir 192.168.1.10(rw,no_root_squash)

That will export the /pathname/rootfsdir to the O2 if the O2's IP is
set to 192.168.1.10. This will give it read-write access, and treat
root on the O2 the same as root on your server PC's drive.

If you want to make sure your system has mountd up and running, connect
to your rootfs by typing at a prompt:

mount localhost:/pathname/rootfsdir /mntdir

If it mounts, then you should be good to go with your O2.

For more information on NFS root, look for the diskless-root-nfs-HOWTO.

4 Setting up the O2

Turn on your O2 and marvel at its sleek stylish case while you wait 45
seconds for it to actually do something. When the monitor finally displays
something, press ESC when the "STOP FOR MAINTENANCE" button appears. Press
'5' to go into the COMMAND MONITOR.

4.1 IP

Type the following in the command monitor:

setenv netaddr 192.168.1.10

That will set your O2 to the IP address listed above. Choose whichever
is appropriate for you.

4.2 Envs

The PROM in the O2 will pass some of its env vars to the Linux kernel.
To properly boot your system, type the following on the command monitor:

setenv OSLoadOptions "nfsroot=SERVER_IP:/pathname/rootfs ip=O2_IP:SERVER_IP"
setenv OSLoadPartition /dev/nfs

Or, if your bootp/dhcp server is set up properly:

setenv OSLoadOptions "ip=dhcp"
setenv OSLoadPartition /dev/nfs

Also, if using serial console, it would be good idea to enable serial
console explicitly by adding "console=ttyS0" option to command line

So if your O2 is 192.168.1.10, and your server linux PC is 192.168.1.103,
and the pathname to your O2's rootfs on your linux PC is /root/sgifs type:

setenv OSLoadOptions "nfsroot=192.168.1.103:/root/sgifs ip=192.168.1.10:192.168.1.103 console=ttyS0"

4.3 Bootp

To boot your O2 and its Linux kernel, type the following:

bootp():

You should see the following from the O2:

Setting $netaddr to 192.168.1.10 (from server)
Obtaining from server
(some numbers)

If bootp(): just hangs, then your Linux PC's dhcpd server isn't set up
properly. If the first line appears but not the second, then tftpd is
not working. Check your Linux PC's /var/log/messages to see what's
going on with your RPC services. You can also type "rpcinfo -p" on your
server PC to make sure portmap and mountd are running. TFTPD won't show
up there, but if portmap is running you should be fine.

If you're lucky, the O2 will get the whole vmlinux file from your
Linux PC, and then display a message like "entry point 0x80200000"
and then boot! You should see the FB come up with the Tux logo.

If your file system doesn't remount as read-write, you probably forgot
to put an entry in /etc/fstab on the root filesystem you're trying to
use. (Not the server's /etc/fstab, but the one in the SGI's fs.)
I did that, so I figured I'd throw that in here. :)

5.0
If you have any comments about this HOWTO, please send them
to Ilya