Linux/MIPS HOWTO

Linux/MIPS HOWTO
Ralf B�chle, [email protected]
v0.1, 31 March 1999

This FAQ describes the MIPS port of the Linux operating system, common
problems and their solutions, availability and more. It also tries to
be a little helpful to other people who might read this FAQ in an
attempt to find information that actually should be covered elsewhere.
______________________________________________________________________

Table of Contents

1. What is Linux/MIPS?

2. What hardware does Linux/MIPS support?

2.1 Hardware platforms
2.1.1 Acer PICA
2.1.2 Baget/MIPS series
2.1.3 Cobalt Qube and Raq
2.1.4 Netpower 100
2.1.5 Nintendo 64
2.1.6 Silicon Graphics Indy
2.1.6.1 Strange numbers of available memory
2.1.6.2 Indy PROM related problems
2.1.6.3 ELF support in old PROM versions
2.1.6.4 Why is so much memory reserved on my Indy?
2.1.7 Silicon Graphics Challenge S
2.1.8 Silicon Graphics Indigo
2.1.9 Serial console on SGI machines
2.1.10 Motorola 68k based machines like the Iris 3000
2.1.11 SGI VisPC
2.1.12 Other Silicon Graphics machines
2.1.13 Sony Playstation
2.1.14 SNI RM200C
2.1.15 SNI RM200
2.1.16 SNI RM300C
2.1.17 SNI RM400
2.1.18 Algorithmics P4032
2.1.19 Algorithmics P5064
2.1.20 DECstation series
2.1.21 Mips Magnum 4000 / Olivetti M700-10
2.1.22 MIPS Magnum 4000SC
2.1.23 VaxStation
2.2 Processor types
2.2.1 R2000, R3000 family
2.2.2 R6000
2.2.3 R4000 and R5000 family
2.2.4 R8000
2.2.5 R10000

3. Linux distributions.

3.1 RedHat
3.2 Debian

4. Linux/MIPS net resources.

4.1 Anonymous FTP servers.
4.2 Anonymous CVS servers.
4.3 Web servers.
4.4 Mailing lists.

5. Installation of Linux/MIPS and common problems.

5.1 NFS booting fails.
5.2 Self compiled kernels crash when booting.
5.3 Booting the kernel on the Indy fails with PROM error messages
5.4 Where can I get the little endian firmware for my SNI?
5.5 ld dies with signal 6

6. Milo

6.1 Building Milo
6.2 Pandora

7. Loadable Modules

8. How do I setup a crosscompiler?

8.1 Diskspace requirements
8.2 Byte order
8.3 Configuration names
8.4 Installation of GNU Binutils.
8.5 Assert.h
8.6 First installation of egcs
8.7 float.h
8.8 Installing the kernel sources
8.9 Installing GNU libc
8.10 Building egcs again
8.11 Should I build the C++, Objective C or F77 compilers?
8.12 GDB

9. Related Literature

9.1 See MIPS Run
9.2 The MIPS Programmer's Handbook
9.3 Computer Architecture - A Quantitative Approach

10. Linux/MIPS news

______________________________________________________________________

1. What is Linux/MIPS?

Linux/MIPS is a port of the widespread UNIX clone Linux to the MIPS
architecture. Linux/MIPS is running on a large number of technically
very different systems ranging from little embedded systems and
servers to large desktop machines and servers that, at least at the
time when they were introduced into the market, were the best of their
class.

Linux/MIPS advantages over other operating systems at this time are

� The entire Linux system consists only of Free Software.

� Excellent Price/Performance ratio.

� Availability of large amounts of software of which a large part
again is Free Software.

� Binary compatibility across a growing number of platforms.

� Small footprint making Linux/MIPS suitable for many embedded
systems.

In short, Linux has been designed and ships with Fahrvergn�gen.
However as usual your mileage may vary and you should examine Linux's
suitability for your purpose which purpose this document tries to
serve.

2. What hardware does Linux/MIPS support?

2.1. Hardware platforms

Many machines are available with a number of different CPU options of
which not all are currently supported. Please check section
``Processor Types'' to make sure your CPU type is supported. This is
a listing of machines that are running Linux/MIPS, systems to which
Linux/MIPS could be ported or systems that people have an interest in
running Linux/MIPS.

2.1.1. Acer PICA

The Acer PICA is derived from the Mips Magnum 4000 design. It has a
R4400PC CPU running at 133Mhz or optionally 150Mhz plus a 512kb
(optionally 2mb) second level cache; the Magnum's G364 gfx card was
replaced with a S3 968 based one. The system is supported with the
exception of the X server.

2.1.2. Baget/MIPS series

The Baget series includes several boxes which have R3000 processors:
Baget 23, Baget 63, and Baget 83. Baget 23 and 63 have BT23-201 or
BT23-202 motherboards with R3500A (which is basically a R3000A chip)
at 25 MHz and R3081E at 50 MHz respectively. The BT23-201 board has
VME bus and VIC068, VAC068 chips as system controllers. The BT23-202
board has PCI as internal bus and VME as internal. Support for
BT23-201 board has been done by Gleb Raiko ([email protected])
and Vladimir Roganov ([email protected]) with a bit help from Serguei
Zimin ([email protected]). Support for BT23-202 is under development
along with Baget 23B which consists of 3 BT23-201 boards with shared
VME bus.

Baget 83 is mentioned here for completeness only. It has only 2mb RAM
and it's too small to run Linux. The Baget/MIPS code has been merged
with the DECstation port; source for both is available at
<http://decstation.unix-ag.org/>.

2.1.3. Cobalt Qube and Raq

The Cobalt Qube product series are low cost headless server systems
based on a IDT R5230. Cobalt has developed its own Linux/MIPS variant
to fit the special requirements of the Qube as well as possible.
Basically the Qube kernel has been derived from Linux/MIPS 2.1.56,
then backported to 2.0.30 for stability's sake, then optimized.
Cobalt kernels are available from Cobalt's ftp site
<http://www.cobaltnet.com>. The Cobalt Qube support has never been
integrated into the official Linux/MIPS 2.1.x kernels.

2.1.4. Netpower 100

The Netpower 100 is apparently an Acer PICA in disguise. It should
therefore be supported but this is untested. If there is a problem
then it is probably the machine detection.

2.1.5. Nintendo 64

The Nintendo 64 is R4300 based game console with 4mb RAM. Its
graphics chips were developed by Silicon Graphics for Nintendo. Right
now this port has pipe dream status and will continue to be in that
state until Nintendo decides to publish the necessary technical
information. The question remains as to whether this is a good idea.

2.1.6. Silicon Graphics Indy

The Indy is currently the only (mostly) supported Silicon Graphics
machine. The only supported graphics card is the Newport card aka
``XL'' graphics. The Indy is available with a large number of CPU
options at various clock rates all of which are supported. There is
currently no X server available for the Indy; Alan Cox
([email protected]) is working on one.

2.1.6.1. Strange numbers of available memory

On bootup the kernel on the Indy will report available memory with a
message like

Memory: 27976k/163372k available (1220k kernel code, 2324k data)

The large difference between the first pair of numbers is caused by a
128mb area in the Indy's memory address space which mirrors up to the
first 128mb of memory. The difference between the two numbers will
always be about 128mb and does not indicate a problem of any kind.

2.1.6.2. Indy PROM related problems

Several people have reported these problems with their machines after
upgrading them typically from surplus parts. There are several PROM
versions for the Indy available. Machines with old PROM versions
which have been upgraded to newer CPU variants like a R4600SC or
R5000SC module can crash during the self test with an error message
like

Exception: <vector=Normal>
Status register: 0x30004803<CU1,CU0,IM7,IM4,IPL=???,MODE=KERNEL,EXL,IE>
Cause register: 0x4000<CE=0,IP7,EXC=INT>
Exception PC: 0xbfc0b598
Interrupt exception
CPU Parity Error Interrupt
Local I/O interrupt register 1: 0x80 <VR/GIO2>
CPU parity error register: 0x80b<B0,B1,B3,SYSAD_PAR>
CPU parity error: address: 0x1fc0b598
NESTED EXCEPTION #1 at EPC: 9fc3df00; first exception at PC: bfc0b598

In that case you'll have to upgrade your machine's PROMs to a newer
version or go back to an older CPU version. Usually R4000SC or
R4400SC modules should work in that case. Just to be clear, this is a
problem which is unrelated to Linux. It's only mentioned here because
several Linux users have asked about it.

2.1.6.3. ELF support in old PROM versions

Old PROM versions don't know about the ELF binary format which the
Linux kernel uses, that is can't boot Linux directly. The preferable
solution for this is of course a PROM upgrade. Alternatively you can
use Sash of IRIX 5 or newer to boot the kernel. Sash knows how to
load ELF binaries and doesn't care if it's an IRIX or Linux kernel.
Simply type ``Sash'' to the prom monitor. You should get another
shell prompt, this time from Sash. Now launch Linux as usual.
Sash can read EFS or XFS filesystems or read the kernel from bootp /
tftp. That means if you intend to use Sash for booting the kernel
from local disk you'll still have to have a minimal IRIX installation
on your system.

2.1.6.4. Why is so much memory reserved on my Indy?

On bootup the `Memory: ...' message on an Indy says that there is
128mb of RAM reserved. That is ok; just like the PC architecture has
a gap in its memory address space between 640kb and 1024kb, the Indy
has a 128mb-sized area in its memory map where the first 128mb of its
memory is mirrored. Linux knows about it and just ignores that
memory, thus this message.

2.1.7. Silicon Graphics Challenge S

This machine is very similar to the Indy; the difference is that it
doesn't have a keyboard and a GFX card but has an additional SCSI
WD33C95 based adapter. This WD33C95 hostadapter is currently not
supported.

2.1.8. Silicon Graphics Indigo

This machine is only being mentioned here because occasionally people
have confused it with Indys. The Indigo series is a different
architecture however and therefore yet unsupported. Andrew R. Baker
([email protected]) announced a university project to port Linux to the
Indigo on January 2, 1999.

2.1.9. Serial console on SGI machines

Make sure the kernel you're using includes the appropriate driver for
a serial interface and serial console. Set the console ARC
environment variable to either the value d1 or d2 for Indy and
Challenge S depending on which serial interface you're going to use as
console.

If you have the problem that all kernel messages appear on the serial
console on bootup but everything is missing from the point when init
starts, then you probably have the wrong setup for your /dev/console.
You can find more information about this in the Linux kernel source
documentation; it's in /usr/src/linux/Documentation/serial-console.txt
if you have the kernel source installed.

2.1.10. Motorola 68k based machines like the Iris 3000

These are very old machines, probably more than ten years old by now.
As these machines are not based on MIPS processors this document is
the wrong place to search for information. However, in order to make
things easy, these machines are currently not supported.

2.1.11. SGI VisPC

This is actually an x86 based system, therefore not covered by this
FAQ. But to make your search for answers simple, here it is. Ken
Klingman ([email protected]) posted on January 17, 1999 to SGI's
Linux mailing list:

We are working on it. We're actually close to getting
the base level system support into the 2.2 release.
Software-only X and OpenGL should follow relatively
shortly, but hardware-accelerated OpenGL is still
some time off. See www.precisioninsight.com for
news about hardware-accelerated OpenGL.

For more information see the Documentation/ of Linux kernel versions
from 2.2.0 and newer. There is additional information available on
the web on <http://www.linux.sgi.com/intel/>. Note that the SGI/MIPS
and SGI/Intel people are working independently of each other, there�
fore the sources in the anonymous CVS on linus.linux.sgi.com may or
may not work for Intel machines; we don't test this.

2.1.12. Other Silicon Graphics machines

At this time no other Silicon Graphics machine is supported. This
also applies to the very old Motorola 68k based systems.

2.1.13. Sony Playstation

The Sony Playstation is based on an R3000 derivative and uses a set of
graphics chips developed by Sony themselves. While the machine in
theory would be capable of running Linux, a port is difficult, since
Sony so far hasn't provided the necessary technical information. This
still leaves the question of whether the port would be worthwhile. So
in short, nothing has happend yet even though many people have shown
their interest in trying Linux on a Playstation so far.

2.1.14. SNI RM200C

In contrast to the RM200 (see below) this machine has EISA and PCI
slots. The RM200 is supported with the exception of the availability
of the onboard NCR53c810A SCSI controller.

2.1.15. SNI RM200

If your machine has both EISA and PCI slots, then it is an RM200C;
please see above. Due to the slight architectural differences of the
RM200 and the RM200C this machine isn't currently supported in the
official sources. Michael Engel ([email protected])
has managed to get his RM200 working partially but the patches haven't
yet been included in the official Linux/MIPS sources.

2.1.16. SNI RM300C

The RM300 is technically very similar to the RM200C. It should be
supported by the current Linux kernel, but we haven't yet received any
reports.

2.1.17. SNI RM400

The RM400 isn't supported.

2.1.18. Algorithmics P4032

The Algorithmics P4032 port is at the time of this writing still
running Linux 2.1.36.

2.1.19. Algorithmics P5064

The P5064 is basically an R5000-based 64bit variant of the P4032.
It's not yet supported but a Linux port will be quite easy.

2.1.20. DECstation series

During the late 80's and the early 90's Digital (now Compaq) built
MIPS based Workstations named DECstation resp. DECsystem. Other x86
and Alpha based machines were sold under the name DECstation, but
these are obviously not subject of this FAQ. Support for DECstations
is still under development, started by Paul M. Antoine. These days
most of the work is done by Harald Koerfgen
([email protected]) and others. On the Internet, DECstation-
related information can be found at <http://decstation.unix-ag.org/>.

The DECstation family ranges from the DECstation 2100 with an
R2000/R2010 chipset at 12 Mhz to the DECstation 5000/260 with a 60 MHz
R4400SC.

The following DECstation models are actively supported:

� 2100, codename PMAX

� 5000/xx (Personal DECstation), codename MAXine

� 5000/1xx, codename 3MIN

� 5000/2x0, codename 3MAX+

� 5900/2x0 (identical to the 3MAX+).

These DECstation models are orphaned because nobody is working on
them, but support for these should be relatively easy to achieve.

� 3100, identical to the 2100 except the R2000A/R2010A @ 16 MHz

� 5100, codename MIPSMATE, almost identical to the 2100 but with an
R3000/R3010 chipset.

� 5000/200, codename 3MAX

The other members of the DECstation family, besides the x86 based
ones, should be considered as VAXen with the CPU replaced by a MIPS
CPU. There is absolutely no information available about these
machines and support for them is unlikely to happen ever unless the
VAXLinux port comes to a new life. These are:

� 5400, codename MIPSFAIR

� 5500, codename MIPSFAIR2

� 5800, codename ISIS

The R2000/R3000 support in the Linux/MIPS kernel is a merge of the
DECstation and Baget/MIPS code and isn't yet integrated into the
official Linux/MIPS source tree.
2.1.21. Mips Magnum 4000 / Olivetti M700-10

These two machines are almost completely identical. Back during the
ACE initiative Olivetti licensed the Jazz design and marketed the
machine with Windows NT as OS. MIPS Computer Systems, Inc. itself
bought the Jazz design and marketed it as the MIPS Magnum 4000 series
of machines. Magnum 4000 systems were marketed with Windows NT and
RISC/os as operating systems.

The firmware on the machine depended on the operating system which was
installed. Linux/MIPS supports only the little endian firmware on
these two types of machines. Since the M700-10 was only marketed as
an NT machine all M700-10 machines have this firmware installed. The
MIPS Magnum case is somewhat more complex. If your machine has been
configured big endian for RISC/os then you need to reload the little
endian firmware. This firmware was originally included on a floppy
with the delivery of every Magnum. If you don't have the floppy
anymore you can download it via anonymous ftp from
<ftp://ftp.fnet.fr>.

It is possible to reconfigure the M700 for headless operation by
setting the firmware environment variables ConsoleIn and ConsoleOut to
multi()serial(0)term(). Also try the command listdev which will show
the available ARC devices.

In some cases, like where the G364 graphics card is missing but the
console is still configured to use normal graphics it will be
necessary to set the configuration jumper JP2 on the board. After the
next reset the machine will reboot with the console on COM2.

2.1.22. MIPS Magnum 4000SC

The Mips Magnum 4000SC is the same as a Magnum 4000 (see above) with
the exception that it uses an R4000SC CPU.

2.1.23. VaxStation

As the name already implies this machine is a member of Digital
Equipment's VAX family. It's mentioned here because people often
confuse it with Digital's MIPS based DECstation family due to the
similar type numbers. These two families of architectures share
little technical similarities. Unfortunately the VaxStation, like the
entire VAX family, is currently unsupported.

2.2.

Processor types

2.2.1. R2000, R3000 family

The R2000 is the original MIPS processor. It's a 32 bit processor
which was clocked at 8MHz back in '85 when the first MIPS processors
came to the market. Later versions were clocked faster: for
instance, the R3000 is a 100% compatible redesign of the R2000, just
clocked faster. Because of their high compatibility, where this
document mentions the R3000, in most cases the same facts also apply
to the R2000.

The R3000A is basically an R2000 plus an R3010 FPU and 64k cache
running at up to 40Mhz and integrated into the same chip. Support for
the R3000 processor is currently in the works by various people.
Harald Koerfgen ([email protected]) and Gleb O. Raiko
([email protected]) have both independently worked on patches which
haven't yet been integrated into the official Linux/MIPS sources.

2.2.2. R6000

Sometimes people confuse the R6000, a MIPS processor, with RS6000, a
series of workstations made by IBM. So if you're reading this in hope
of finding out more about Linux on IBM machines you're reading the
wrong document.

The R6000 is currently not supported. It is a 32-bit MIPS ISA 2
processor and a pretty interesting and weird piece of silicon. It was
developed and produced by a company named BIT Technology. Later NEC
took over the semiconductor production. It was built in ECL
technology, the same technology that was and still is being used to
build extremely fast chips like those used in some Cray computers.
The processor had its TLB implemented as part of the last couple of
lines of the external primary cache, a technology called TLB slice.
That means its MMU is substantially different from those of the R3000
or R4000 series, which is also one of the reasons why the processor
isn't supported.

2.2.3. R4000 and R5000 family

Linux supports many of the members of the R4000 family. Currently
these are R4000PC, R4400PC, R4300, R4600, R4700, R5000, R5230, R5260.
Many others are probably working as well.

Not supported are R4000MC and R4400MC CPUs (that is multiprocessor
systems) as well as R5000 systems with a CPU controlled second level
cache. This means where the cache is controlled by the R5000 itself
in contrast to some external external cache controller. The
difference is important because, unlike other systems, especially PCs,
on MIPS the cache is architecturally visible and needs to be
controlled by software.

Special credit goes to Ulf Carlsson ([email protected]) who provided
the CPU module for debugging the R4000SC / R4400SC support.

2.2.4. R8000

The R8000 is currently unsupported partly because this processor is
relatively rare and has only been used in a few SGI machines, partly
because the Linux/MIPS developers don't have such a machine.

The R8000 is a pretty interesting piece of silicon. Unlike the other
members of the MIPS family it is a set of seven chips. Its cache and
TLB architecture is pretty different from the other members of the
MIPS family. It was born as a hack to get the floating point crown
back to Silicon Graphics before the R10000 is finished.

2.2.5. R10000

The R10000 is currently unsupported because the Linux/MIPS developers
don't have an R10000 machine.

3. Linux distributions.

3.1. RedHat

For MIPSeb, there's Rough Cuts Linux, previously known as Hard Hat
Linux, which is most of Red Hat Linux 5.1 ported for MIPSeb. You can
get this at <ftp://ftp.linux.sgi.com/pub/hardhat>.

It is also bundled along with M68k, UltraSparc and PowerPC in a
package called "Rough Cuts" pressed by Red Hat, and available wherever
Red Hat products are sold. This is a very convenient way to get it
without having to download 280MB. You can order Rough Cuts directly
from Red Hat at <http://www.redhat.com/product.phtml/RC1000>.

As well, there's a distribution based on Red Hat 5.2 that's targetting
the Cobalt Qubes; those binaries will work perfectly on other MIPSel
architectures available at <ftp://intel.cleveland.lug.net/pub/Mipsel>.

3.2. Debian

A Debian port is underway. Current efforts are being bootstrapped
using SGI/Linux as a base, and dpkg compiles natively with few
changes. In addition to the SGI version, some interest has been shown
in little endian platforms. Keep an eye on the Debian-MIPS Port page,
<http://www.debian.org/ports/mips/> for developments.

4. Linux/MIPS net resources.

4.1. Anonymous FTP servers.

The two primary anonymous FTP servers for Linux/MIPS are

ftp.linux.sgi.com
This server should satisfy almost all your Linux/MIPS related
ftp desires. Really.

ftp.fnet.fr
This server is currently pretty outdated; it's included here
mostly for completeness and for people with interest in
prehistoric software.

On all these ftp servers there is a list of mirror sites you may want
to use for faster access.

4.2. Anonymous CVS servers.

For those who always want to stay on the bleeding edge and want to
avoid having to download patch files or full tarballs we also have an
anonymous CVS server. Using CVS you can checkout the Linux/MIPS
source tree with the following commands:

cvs -d :pserver:[email protected]:/cvs login
(Only needed the first time you use anonymous CVS, the password is "cvs")
cvs -d :pserver:[email protected]:/cvs co <repository>

where you insert linux, libc, or gdb for <repository>.

The other important CVS archive of the Linux community is
vger.rutgers.edu where a lot of code is being collected before being
sent to Linus for distribution. Although vger itself no longer offers
anonymous access, there are mirror sites which do provide anonymous
access. For details how to access them see
<http://cvs.on.openprojects.net/>. The modules which are of interest
are ``linux'', ``modutils'', ``pciutils'', ``netutils''.

4.3. Web servers.

The two primary anonymous web servers for Linux/MIPS are

www.linux.sgi.com
This server covers most of Linux/MIPS; it's somewhat SGI centric
but since Linux/MIPS tries to be the same on every platform most
of its information is of interest to all users.

lena.fnet.fr
This server is currently pretty outdated; it's included here
mostly for completeness.

All these servers have mirrors scattered all over the world; you may
want to use one for best performance.

4.4. Mailing lists.

There are three Linux/MIPS oriented mailing lists:

[email protected]
This mailing list is used for most non-SGI related communication
of all kinds. Subscription is handled by a human; send your
subscription requests to [email protected]. You can
unsubscribe from this mailing list by sending unsubscribe <your-
email-address> to the same address.

[email protected]
This mailing list currently has the most traffic. It's somewhat
SGI-centric but is nevertheless of interest especially to
developers as a good number of SGI engineers are subscribed to
this list. Subscription to this list is handled via Majordomo
([email protected]); just send an email with the words
subscribe linux-mips. In order to unsubscribe send unsubscribe
linux-mips. Note that you have to be subscribed if you want to
post; the growth of spam forced us into that policy.

[email protected]
This mailing list has only very low traffic as most people tend
to use one of the above mailing lists. Subscription is handled
via Majordomo ([email protected]); just send an email
with the words subscribe linux-mips. In order to unsubscribe
send unsubscribe linux-mips.

5. Installation of Linux/MIPS and common problems.

5.1. NFS booting fails.

Usually the reason for this is that people have unpacked the tar
archive under IRIX, not Linux. Since the representation of device
files over NFS is not standardized between various Unices, this fails.
The symptom is that the system dies with the error message ``Warning:
unable to open an initial console.'' right after mounting the NFS
filesystem.

For now the workaround is to use a Linux system (doesn't need to be
MIPS) to unpack the installation archive onto the NFS server. The NFS
server itself may be any type of UNIX.

5.2. Self compiled kernels crash when booting.

When I build my own kernel, it crashes. On an Indy the crash message
looks like the following; the same problem hits other machines as well
but may look completely different.

Exception: <vector=UTLB Miss>
Status register: 0x300004803<CU1,CU0,IM4,IPL=???,MODE=KERNEL,EXL,IE>
Cause register: 0x8008<CE=0,IP8,EXC=RMISS>
Exception PC: 0x881385cc, Exception RA: 0x88002614
exception, bad address: 0x47c4
Local I/O interrupt register 1: 0x80 <VR/GIO2>
Saved user regs in hex (&gpda 0xa8740e48, &_regs 0xa8741048):
arg: 7 8bfff938 8bfffc4d 880025dc
tmp: 8818c14c 8818c14c 10 881510c4 14 8bfad9e0 0 48
sve: 8bfdf3e8 8bfffc40 8bfb2720 8bfff938 a8747420 9fc56394 0 9fc56394
t8 48 t9 8bfffee66 at 1 v0 0 v1 8bfff890 k1 bad11bad
gp 881dfd90 fp 9fc4be88 sp 8bfff8b8 ra 88002614

PANIC: Unexpected exception

This problem is caused by a still unfixed bug in Binutils newer than
version 2.7. As a workaround, change the following line in
arch/mips/Makefile from:

LINKFLAGS = -static -N

to:

LINKFLAGS = -static

5.3. Booting the kernel on the Indy fails with PROM error messages

>> boot bootp()/vmlinux
73264+592+11520+331680+27848d+3628+5792 entry: 0x8df9a960
Setting $netaddres to 192.168.1.5 (from server deadmoon)
Obtaining /vmlinux from server deadmoon

Cannot load bootp()/vmlinux
Illegal f_magic number 0x7f45, expected MIPSELMAGIC or MIPSEBMAGIC.

This problem only happens for Indys with very old PROM versions which
cannot handle the ELF binary format which Linux uses. A solution for
this problem is in the works.

5.4. Where can I get the little endian firmware for my SNI?

SNI's system can be operated in both big and little endian modes. At
this time Linux/MIPS only supports the little endian firmware. This
is somewhat unlucky since SNI hasn't shipped that firmware for quite
some time, since they dropped NT.

When running in big endian mode the firmware looks similar to an SGI
Indy which is already supported, therefore fixing the SNI support will
be relativly easy. Interested hackers should contact Ralf B�chle
([email protected]).

5.5. ld dies with signal 6

collect2: ld terminated with signal 6 [Aborted]

This is a known bug in older binutils versions. You will have to
upgrade to binutils 2.8.1 plus very current patches.

6. Milo

Milo is the boot loader used to boot the little endian MIPS systems
with ARC firmware, currently the Jazz family and the SNI RM 200.
While Milo uses the same name and has a similar purpose to the Alpha
version of Milo, these two Milos have nothing else in common. They
were developed by different people, don't share any code, and work on
different hardware platforms. The fact that both have the same name
is just a kind of historic ``accident''.

Plans are to remove the need for Milo in the near future.

6.1. Building Milo

The building procedure of Milo is described in detail in the README
files in the Milo package. Since Milo has some dependencies to kernel
header files which have changed over time Milo often cannot be built
easily; however the Milo distribution includes binaries for both Milo
and Pandora.

6.2. Pandora

Pandora is a simple debugger. It has been primarily developed in
order to analyze undocumented systems. Pandora includes a
dissassembler, memory dump functions and more. If you only want to
use Linux there is no need to install Pandora. It's small though.

7. Loadable Modules

Using modules on Linux/MIPS is quite easy; it should work as expected
for people who have used it on other Linux systems. If you want to
run a module-based system then you should have at least kernel version
980919 and modutils newer than version 2.1.121 installed. Older
versions won't work.
8. How do I setup a crosscompiler?

First of all go and download the following source packages:

� binutils-2.8.1.tar.gz

� egcs-1.0.2.tar.gz

� glibc-2.0.6.tar.gz

� glibc-crypt-2.0.6.tar.gz

� glibc-localedata-2.0.6.tar.gz

� glibc-linuxthreads-2.0.6.tar.gz

These are the currently recommended versions. Older versions may
or may not be working. If you're trying to use older versions
please don't send bug reports; we don't care. When installing
please install things in the order binutils, egcs, then glibc.
Unless you have older versions already installed, changing the
order will fail. The installation description below mentions a
number of patches which you can get from the respective SRPM
packages on ftp.linux.sgi.com. However since these SRPM packages
are intended to be compiled natively it's not possible to just
rebuild them.

8.1. Diskspace requirements

For the installation you'll have to choose a directory for
installation. I'll refer to that directory below with <prefix>. To
avoid a certain problem it's best to use the same value for <prefix>
as your native gcc. For example if your gcc is installed in
/usr/bin/gcc then choose /usr for <prefix>. You must use the same
<prefix> value for all the packages that you're going to install.

During compilation you'll need about 31mb diskspace for binutils; for
installation you'll need 7mb diskspace for on <prefix>'s partition.
Building egcs requires 71mb and installation 14mb. GNU libc requires
149mb diskspace during compilation and 33mb for installation. Note
these numbers are just a guideline and may differ significantly for
different processor and operating system architectures.

8.2. Byte order

One of the special features of the MIPS architecture is that all
processors except the R8000 can be configured to run either in big or
in little endian mode. Byte order means the way the processor stores
multibyte numbers in memory. Big endian machines store the byte with
the highest value digits at the lowest address while little endian
machines store it at the highest address. Think of it as writing
multi-digit numbers from left to right or vice versa.

In order to setup your crosscompiler correctly you have to know the
byte order of the crosscompiler target. If you don't already know,
check the section ``Hardware Platforms'' for your machine's byteorder.

8.3. Configuration names

Many of the packages based on autoconf support many different
architectures and operating systems. In order to differentiate
between these many configurations, names are constructed with
<cpu>-<company>-<os> or even <cpu>-<company>-<kernel>-<os>. Expressed
this way the configuration names of Linux/MIPS are mips-unknown-linux-
gnu for big endian targets or mipsel-unknown-linux-gnu for little
endian targets. These names are a bit long and are allowed to be
abbreviated to mips-linux or mipsel-linux. You must use the same
configuration name for all packages that comprise your
crosscompilation environment. Also, while other names like mips-sni-
linux or mipsel-sni-linux are legal configuration names, use mips-
linux or mipsel-linux instead; these are the configuration names known
to other packages like the Linux kernel sources and they'd otherwise
have to be changed for crosscompilation.

I'll refer to the target configuration name below with <target>.

8.4. Installation of GNU Binutils.

This is the first and simplest part - at least as long as you're
trying to install on any halfway-sane UNIX flavour. Just cd into a
directory with enough free space and do the following:

gzip -cd binutils-<version>.tar.gz | tar xf -
cd binutils-<version>
patch -p1 < ../binutils-<version>-mips.patch
./configure --prefix=<prefix> --target=<target>
make CFLAGS=-O2
make install

This usually works very easily. On certain machines using GCC 2.7.x
as compiler is known to dump core. This is a known bug in GCC and can
be fixed by upgrading to GCC 2.8.1 or egcs.

8.5. Assert.h

Some people have an old assert.h headerfile installed, probably a
leftover from an old crosscompiler installation. This file may cause
autoconf scripts to fail silently; it was never necessary and was only
installed because of a bug in older GCC versions. Check to see if the
file <prefix>/<target>/include/assert.h exists in your installation.
If so, just delete the it: it should never have been installed.

8.6. First installation of egcs

Now the not-so-funny part begins: there is a so-called bootstrap
problem. In our case that means the installation process of egcs
needs an already- installed glibc, but we cannot compile glibc because
we don't have a working crosscompiler yet. Luckily you'll only have
to go through this once when you install a crosscompiler for the first
time. Later when you already have glibc installed things will be much
smoother. So now do:

gzip -cd egcs-<version>.tar.gz | tar xf -
cd egcs-<version>
for i in egcs-1.0.2-libio.patch egcs-1.0.2-hjl.patch \
egcs-1.0.2-rth1.patch egcs-1.0.2-rth2.patch egcs-1.0.2-rth3.patch \
egcs-1.0.2-rth4.patch egcs-1.0.2-hjl2.patch egcs-1.0.2-jim.patch \
egcs-1.0.2-haifa.patch egcs-1.0.1-objcbackend.patch \
egcs-1.0.2-mips.patch; do patch -p1 -d < ../$i; done
./configure --prefix=<prefix> --with-newlib --target=<target>
cd gcc
make LANGUAGES="c"

Note that we deliberately don't build gcov, protoize, unprotoize and
the libraries. Gcov doesn't make sense in a crosscompiler environment
and protoize and unprotoize might even overwrite your native programs
- this is a bug in the gcc makefiles. Finally we cannot build the
libraries because we don't have glibc installed yet. If everything
went successfully, install with:

make LANGUAGES="c" install

8.7. float.h

Another bootstrap problem is that building GCC requires running
programs on the machine for which GCC will generate code, but since a
crosscompiler is running on a different type of machine this cannot
work. When building GCC this happens for the header file float.h.
Luckily there is a simple solution: download the header file from one
of the Linux/MIPS ftp servers or rip it from one of the native
Linux/MIPS binary packages. Later when recompiling or upgrading egcs
usually the already-installed float.h file will do because float.h
changes rarely. Install it with:

cp float.h <prefix>/<target/<version>/include/float.h

where <version> is the internal version number of the egcs version
you're using. For egcs 1.0.2 for example you would use egcs-2.90.27
for <version>. If not sure - ls is your friend.

8.8. Installing the kernel sources

Installing the kernel sources is simple. Just place them into some
directory of your choice and configure them such that some files which
are generated by the procedure will be installed. This works the same
as you're used to when configuring the kernel sources for native
compilation. The only problem you may run into is that you may need
to install some required GNU programs like bash or have to override
the manufacturer-provided versions of programs by placing the GNU
versions earlier in the PATH variable. When configuring you should
answer the question ``Are you using a crosscompiler'', that is the
option CONFIG_CROSSCOMPILE, with ``yes''. When you're done with
configuring type make clean; make depend; make. The last make command
will generate the header file <linux/version.h> which compiling some
programs depends on. This file is generated right at the beginning of
the make command, so if you're not interested in actually building a
kernel you may interrupt the compilation after this file has been
built. It may be a good idea, however, to compile the kernel as a
test for your newly-built crosscompiler.

If you only want the crosscompiler for building the kernel, you're
done. Crosscompiling libc is only required to be able to compile
user applications.

8.9. Installing GNU libc

Do:

gzip -cd glibc-2.0.6.tar.gz | tar xf -
cd glibc-2.0.6
gzip -cd glibc-crypt-2.0.6.tar.gz | tar xf -
gzip -cd glibc-localedata-2.0.6.tar.gz | tar xf -
gzip -cd glibc-linuxthreads-2.0.6.tar.gz | tar xf -
patch -p1 < ../glibc-2.0.6-mips.patch
mkdir build
cd build
CC=<target>-gcc BUILD_CC=gcc AR=<target>-ar RANLIB=<target>-ranlib \
../configure --prefix=/usr --host=<target> \
--enable-add-ons=crypt,linuxthreads,localedata --enable-profile
make

You now have a compiled GNU libc which still needs to be installed.
Do not just type make install. That would overwrite your host sys�
tem's files with Linux/MIPS-specific files with disastrous effects.
Instead install GNU libc into some other arbitrary directory <somedir>
from which we'll move the parts we need for crosscompilation into the
actual target directory:

make install_root=<somedir> install

Now cd into <somedir> and finally install GNU libc manually:

cd usr/include
find . -print | cpio -pumd <prefix>/<target>/include
cd ../../lib
find . -print | cpio -pumd <prefix>/<target>/lib
cd ../usr/lib
find . -print | cpio -pumd <prefix>/<target>/lib

GNU libc also contains extensive online documentation. Your systems
might already have a version of this documentation installed, so if
you don't want to install the info pages, which will save you a less
than a megabyte, or already have them installed, skip the next step:

cd ../info
gzip -9 *.info*
find . -name \*.info\* -print | cpio -pumd <prefix>/info

If you're not bootstrapping your installation is now finished.

8.10. Building egcs again

The first attempt of building egcs was stopped by lack of a GNU libc.
Since we now have libc installed we can rebuild egcs but this time as
complete as a crosscompiler installation can be:

gzip -cd egcs-<version>.tar.gz | tar xf -
cd egcs-<version>
for i in egcs-1.0.2-libio.patch egcs-1.0.2-hjl.patch \
egcs-1.0.2-rth1.patch egcs-1.0.2-rth2.patch egcs-1.0.2-rth3.patch \
egcs-1.0.2-rth4.patch egcs-1.0.2-hjl2.patch egcs-1.0.2-jim.patch \
egcs-1.0.2-haifa.patch egcs-1.0.1-objcbackend.patch \
egcs-1.0.2-mips.patch; do patch -p1 < ../$i; done
./configure --prefix=<prefix> --target=<target>
make LANGUAGES="c c++ objective-c f77"

As you can see the procedure is the same as the first time with the
exception that we dropped the --with-newlib option. This option was
necessary to avoid the libgcc build breaking due to the lack of libc.
Now install with:

make LANGUAGES="c c++ objective-c f77" install

You're almost finished. All you have left to do now is to reinstall
float.h, which has been overwritten by the last make install command.
You'll have to do this every time you reinstall egcs as a crosscom�
piler. If you think you don't need the Objective C or F77 compilers
you can omit them from above commands; each will save you about 3mb.
Do not build gcov, protoize or unprotoize.

8.11. Should I build the C++, Objective C or F77 compilers?

The answer to this question largely depends on your use of your
crosscompiler environment. If you only intend to rebuild the Linux
kernel then you have no need for the full blown setup and can safely
omit the Objective C and F77 compilers. You must, however, build the
C++ compiler, because building the libraries included with the egcs
distribution requires C++.

8.12. GDB

Building GDB as crossdebugger is only of interest to kernel
developers; for them GDB may be a life saver. Such a remote debugging
setup always consists of two parts: the remote debugger GDB running
on one machine and the target machine running the Linux/MIPS kernel
being debugged. The machines are typically interconnected with a
serial line. The target machine's kernel needs to be equipped with a
``debugging stub'' which communicates with the GDB host machine using
the remote serial protocol.

Depending on the target's architecture you may have to implement the
debugging stub yourself. In general you'll only have to write very
simple routines for serial. The task is further simplified by the
fact that most machines are using similar serial hardware typically
based on the 8250, 16450 or derivatives.

9. Related Literature

9.1. See MIPS Run

author Dominic Sweetman, published Morgan Kaufmann, ISBN
1-55860-410-3.

This is intended as a pretty comprehensive guide to programming MIPS,
wherever it's different from programming any other 32-bit CPU. It's
the first time anyone tried to write a readable and comprehensive
explanation and account of the wide range of MIPS CPUs available, and
should be very helpful for anyone programming MIPS who isn't insulated
by someone else's operating system. And the author is a free-unix
enthusiast who subscribes to the Linux/MIPS mailing list!

John Hennessey, father of the MIPS architecture, was kind enough to
write in the foreword: `` ... this book is the best combination of
completeness and readability of any book on the MIPS architecture
...''

It includes some context about RISC CPUs, a description of the
architecture and instruction set including the "co-processor 0"
instructions used for CPU control; sections on caches, exceptions,
memory management and floating point. There's a detailed assembly
language guide, some stuff about porting, and some fairly heavy-duty
software examples.

Available from:

� <http://www.algor.co.uk/algor/info/seemipsrun.html> (europe)

� <http://www.mkp.com/books_catalog/1-55860-410-3.asp> (US)

and from good bookshops anywhere. It's 512 pages and costs around $50
in the US, �39.95 in the UK.

I'd be inclined to list two other books too, both from Morgan Kaufmann
and available from www.mkp.com or any good bookshop:

9.2. The MIPS Programmer's Handbook

authors Farquhar and Bunce, published by Morgan Kaufmann,
ISBN 1-55860-297-6.

A readable introduction to the practice of programming MIPS at the low
level, by the author of PMON. Strengths: lots of examples; weakness:
leaves out some big pieces of the architecture (such as memory
management, floating point and advanced caches) because they didn't
feature in the LSI ``embedded'' products this book was meant to
partner.

9.3. Computer Architecture - A Quantitative Approach

authors Hennessy & Patterson, published Morgan Kaufmann,
ISBN 1-58860-329-8.

The bible of modern computer architecture and a must-read if you want
to understand what makes programs run slow or fast. Is it about MIPS?
Well, it's mostly about something very like MIPS... Its sole defect
is its size and weight - but unlike most big books it's worth every
page.

10. Linux/MIPS news

Some of this chapter is pretty historic ...

04-Dec-98
Ariel Faigon announces that SGI has joined Linux International.

13-Oct-98
Ralf B�chle fixes the support for R4000SC / R4400SC CPUs.

12-Oct-98
Vladimir Roganov reports that his R3000 system is now stable
enough to compile GDB.

03-Oct-98
Harald K�rfgen reports that his DECstation 5000/133 is now
running single user. Congratulations!

29-Sep-98
Ralf starts rewriting this FAQ to fit with reality.

10-Jun-98
ftp.linux.sgi.com now offers anonymous CVS access.

01-Feb-98
First commercial Linux/MIPS based product accounced.

26-Jan-98
One more timewarp in this list because the maintainer is
lazy^H^H^H^H busy coding. The driver for the NCR53c8xx has been
modified and has been successfully tested with several machines,
most notably the SNI RM200. Even better, the initial version
seems to be reliable.

Already some time ago Thomas Bogend�rfer implemented the
necessary changes to the NCR53C9x driver aka ESP driver, so
there is now SCSI support for the builtin hostadapters in the
Mips Magnum 4000, Olivetti M700-10 and Acer PICA.

28-Nov-97
First public release of X11 client binaries.

30-Aug-97
Duh, time warp in this page once again. A lot has happend in
the meantime and the maintainer of this pages is a lazy person
that rather prefers to code and hack than write docs...

SGI now has its own Linux/MIPS server reachable as
http://www.linux.sgi.com, with lots of SGI specific information
and many links. The server is also reachable under
ftp.linux.sgi.com. In addition to binaries, sources and docs
specific to Silicon Graphic machines this server also has all
the other Linux/MIPS stuff in stock. Only available on this
server is the developers' cvs archive for download. Sorry, no
anonymous CVS yet.

Silicon Graphics has supported some of the Linux key developers'
work on Linux/MIPS with hardware. As a result the work is now
advancing more quickly and Ralf is no longer the lone workhorse
...

Already available for some time the Indy port is now in the
standard kernel source tree.

Long missing, but finally there: Thomas Bogendoerfer contributed
patches to the NCR53C9x driver for Mips Magnum 4000, Olivetti
M700 and Acer PICA.

Many more packages of a RedHat port to MIPS are now available
for ftp download. Installing is still more a thing for experts
... but we're working on it!

Eeecmacs lovers will be pleased to hear that this FAQ has been
edited by Emacs running on a Linux/MIPS machine.

6-May-97
David Monro releases version 1.01 of bfsd. bfsd is a daemon
that can be used to boot the machines built by Mips
Computersystems, Inc. over a network.

10-Jun-96
Release of Linux/MIPS kernel 2.0.4. This release features a
partially rewritten signal handler that should match POSIX.1.

3-Jun-96
First release of shared libraries for Linux/MIPS based on GNU
libc snapshot 960619.

Release of Linux/MIPS kernel 2.0.1.

25-May-96
David S. Miller starts working on SGI support at Silicon
Graphics.

20-May-96
Release 1.3.98 of the kernel adds support for the SNI RM200 PCI.

27-Mar-96
Linux/MIPS works as NFS server.

The IDE CD driver now also supports Linux/MIPS.

24-Mar-96
Added reference to literature available online form SGI to the
FAQ.

23-Mar-96
New chapter in the FAQ about the ARC standard.

27-Jan-96
Release of Milo 0.26 and a kernel patch to use it. This release
passes parameters to the kernel in a completly different way
that makes porting Linux/MIPS to another architecture a lot
easier.

24-Jan-96
Release of crosscompiler binaries based on the FSF's Binutils
version 2.6. This release brings lots of new features and many
bugfixes.

21-Jan-96
Warner Losh started working on a port of Linux/MIPS to
Deskstation rPC44.

20-Jan-96
Linux/MIPS kernel updated to version 1.3.58.

Patch gcc-2.7.2-1.diffs.gz has been released.

Patch binutils-2.6-1.diffs.gz has been released. This patch
contains lots of bugfixes. The Linux kernel Makefiles will
automatically detect whether Binutils 2.6 or an older version is
installed and use the new features resulting in a much smaller
kernel executable which is especially useful for bootdisks.

15-Jan-96
Release of a complete root and /usr filesystem that can be NFS
mounted to use a Linux/MIPS system as a diskless client. A
native development kit based on GCC 2.7.2, Binutils 2.6 and GNU
libc snapshot 951218 is included as well as many of the standard
utilities.

25-Dec-95
Linux/MIPS boots off an NFS filesystem as a diskless client.
This also means that the rest of Linux/MIPS networking is
operational now.

7-Jan-95
Soft-N-Hard GMBH and SNI sign a contract. SNI will loan an
RM200 to Soft-N-Hard for porting Linux/MIPS to it.

22-Sep-95
The Linux/MIPS FTP archive and mailing list have been moved to
fnet.fr. (There is much more news I currently have no time to
document)

18-Jul-95
New crossdevelopment tools released. GCC-2.6.3-2 and
Binutils-2.5.2-2 for Linux/i386 need kernels with ELF support
and libc-5.0.9 installed. The new crossdev tools are required
for Linux/MIPS kernels above 1.2.9. A.out versions of the
crossdev tools will follow soon.

14-Jul-95
We have a working shell!

12-Jul-95
Patches 2.6.3-2 for Linux/MIPS GCC released. This compiler
better complies with the MIPS standard of symbol names.

10-Jul-95
Linux/MIPS kernel 1.2.9 released.

9-Jun-95
Milo 0.24 released. This version features improved machine type
detection and many cleanups and bugfixes.

24-May-95
Linux/MIPS kernel 1.2.8 released. This version features many
bugfixes and has the Magnum 4000 specific changes from
Linux-1.2.7 integrated.

Milo 0.23 released. This version features built-in support for
Olivetti M700 machines. Milo is now split into two binaries: A
simple bootloader and a standalone debugger/monitor with boot
capability.

23-5-95
Linux/MIPS kernel 1.2.7 on Olivetti M700 mounts root file
system.

22-May-95
Linux/MIPS kernel 1.2.7 on Mips Magnum 4000 mounts root file
system.

Added NEC RiscStation and RiscServer to target list.

Milo 0.22 successfully tested on NEC RiscStation and RiscServer.

18-May-95
Linux/MIPS kernel 1.2.7 released. This release features initial
Magnum 4000 support and tons of bugfixes.

12-May-95
Milo 0.22 released. This version contains some cleanups and
several bugfixes.

5-May-95
The Linux/MIPS archive is now also available from
ftp://ftp.mcc.ac.uk/pub/linux/MIPS.

3-May-95
Milo 0.21 released. This version features more built-in
debugger/monitor commands and contains some important bug fixes.

30-Apr-95
Milo 0.20 released. This version features a built-in
debugger/monitor and a lot of new library functions.

Port to Olivetti M700 started.

26-Apr-95
Linux/MIPS kernel 1.2.6 released.

13-Apr-95
Milo 0.19 released. This version includes some minor fixes plus
initial support for kernels in ELF format.

13-Apr-95
Milo 0.18b released. This version includes support for Mips
Magnum 4000. Port to Mips Magnum 4000 started.

27-Mar-95
Linux/MIPS kernel 1.2.2 released. Kernel now mounts its root
file system.

22-Mar-95
Milo 0.18 released. This version includes support for
Deskstation rPC44 systems.

Port to DeskStation rPC44 started.