path: root/tools-src/gnu/mipsel-linux-cross-toolchain-building.txt

Building a Modern MIPS Cross-Toolchain for Linux

Bradley D. LaRonde

brad@ltc.com

Revision History                                                               
Revision 2.4              2002-09-25            Revised by: bdl                
Update to gcc 3.2, binutils 2.13, glibc 2.2.5.                                 
Revision 2.3              2002-07-15            Revised by: bdl                
Update to gcc 3.0.4, binutils 2.12. Drop back to glibc 2.2.3.                  
Revision 2.2              2002-02-18            Revised by: bdl                
Update to binutils-2.11.92.0.12.3, gcc 3.0.3, and glibc-2.2.4. Use --prefix=/  
usr for glibc's special Linux support. Use --disable-sanity-checks for building
glibc-2.2.4 with gcc 3.0.3.                                                    
Revision 2.1              2001-11-05            Revised by: bdl                
Make it a little less endian-biased.                                           
Revision 2.0              2001-11-02            Revised by: bdl                
Convert to docbook. Correct some typos. GFDL license. Note about endianness.   
Revision 1.9              2001-09-26            Revised by: bdl                
Clarify which libc.so to edit and provide example. Corrected spelling of       
Canadian (Geoffrey Espin). Add wget commands (Geoffrey Espin). Clarify         
$LINUX_SRC (Geoffrey Espin). Correct glibc tar file name (Geoffrey Espin).     
Revision 1.8              2001-09-09            Revised by: bdl                
Add source locations.                                                          
Revision 1.7              2001-09-06            Revised by: bdl                
Correct a typo in the final gcc configure.                                     
Revision 1.6              2001-08-22            Revised by: bdl                
Clarify basic tool list.                                                       
Revision 1.5              2001-08-22            Revised by: bdl                
Upgrade gcc 3.0 branch to gcc 3.0.1 release.                                   
Revision 1.4              2001-08-14            Revised by: bdl                
gcc 3.0 release is broken for C++; use cvs 3.0 branch version.                 
Revision 1.3              2001-08-13            Revised by: bdl                
Slightly adjust step 6 now that I've tested it.                                
Revision 1.2              2001-08-12            Revised by: bdl                
Correct glibc patch info. Correct glibc prefix advice, twice.                  
Revision 1.1              2001-08-11            Revised by: bdl                
Add information about toolchain --prefix failures. Add information about glibc 
--prefix versus install_root. Add warning about installing cross-built stuff.  
Revision 1.0              2001-08-09            Revised by: bdl                
Correct binutils version inconsistency. s/cd cd/cd in final compiler step.     

This document shows the reader how to build a modern MIPS cross-toolchain for
Linux from scratch. It includes valuable tips and step-by-step procedures.

-------------------------------------------------------------------------------
-------------------------------------------------------------------------------

Introduction

The main problem with building a a cross-toolchain (or any toolchain, to a
lesser degree) is that it takes so long to figure out that you did something
wrong. 

This document is mainly a way for me to remember how I did it once so I can do
it again later. Maybe it will help someone else too. 

During this process, I explored the "minimum required configuration" for
building a modern MIPS cross-toolchain for Linux. What I mean by "minimum
required configuration" is something akin to the "minimum amount of typing". I
went as light as I knew how on the configure arguments, and only brought in
patches when something was obviously broken. This was a personal exploration of
mine, and by no means do I mean to imply that the "minimum" I've "found" is the
best; only it is the minimum that I've found that works (thus far). It might
help mitigate some of the configuration mystery that surrounds the scant
information about cross-building that I dug up, beged for, stumbled across,
etc. Yet even as simple as I've reduced it, the whole remains sufficiently
mysterious. 

-------------------------------------------------------------------------------

Copyright Information

Copyright (c) 2001 Bradley D. LaRonde

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 no Invariant Sections, with no
Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is
included in the section entitled "GNU Free Documentation License".

-------------------------------------------------------------------------------

Disclaimer

No liability for the contents of this documents can be accepted. Use the
concepts, examples and other content at your own risk. As this is a new edition
of this document, there may be errors and inaccuracies, that may of course be
damaging to your system. Proceed with caution, and although this is highly
unlikely, the author(s) do not take any responsibility for that.

All copyrights are held by their by their respective owners, unless
specifically noted otherwise. Use of a term in this document should not be
regarded as affecting the validity of any trademark or service mark.

Naming of particular products or brands should not be seen as endorsements.

You are strongly recommended to take a backup of your system before major
installation and backups at regular intervals.

-------------------------------------------------------------------------------

New Versions

I will keep the latest versions of this document updated on my my website in a
variety of formats: 

  * single HTML file: http://www.ltc.com/~brad/mips/mips-cross-toolchain.html 
   
  * HTML file per section: http://www.ltc.com/~brad/mips/mips-cross-toolchain/ 
   
  * Plain text: http://www.ltc.com/~brad/mips/mips-cross-toolchain.txt 
   
  * SGML source: http://www.ltc.com/~brad/mips/mips-cross-toolchain.sgml 
   
 

-------------------------------------------------------------------------------

Credits

  * Geoffrey Espin for several imrovements and corrections.
   
  * Ian Chilton for helping me prove it works.
   
  * Ralf Bächle for his ongoing contribution to linux-mips.
   
  * The greater linux-mips community for the tools themselves.
   
 

-------------------------------------------------------------------------------

Feedback

I value your feedback. Please e-mail me at <brad@ltc.com>.  

-------------------------------------------------------------------------------

Foundation

Understanding Build, Host, and Target Systems

When cross-compiling, you are dealing with at least two systems. One is the
"build" system; i.e. the system used to build the cross-tools. Another is the
"target" system, which is the system the cross-tools will produce code for. 

Then there is the "host" system, which is the system the cross-tools will run
on. Commonly the "build" and "host" systems are the same. That's the situaion
I've covered in this document. When they aren't, you end up in a "Canadian
Cross" situaion, which I won't cover here (and know little to nothing about,
despite the fact that I have a Canadian work visa). 

-------------------------------------------------------------------------------

Building Cross-Toolchains

The general idea is to use the "build" system to create binutils and gcc for
the "host" system that produce code for the "target" system. As I said before,
In my case, the "build" and "host" systems are the same (both i386-linux), and
the "target" system is mipsel-linux or mips-linux (depending on little or big
endian). 

Once you have the binutils and gcc, you can cross-build glibc. Here's the catch
though - you need parts of glibc to build all of gcc. Ugh. So, you need to
build gcc in two steps. First you have to build just the static C compiler,
then after glibc is built and installed, you can build the final C and C++
compilers. 

-------------------------------------------------------------------------------

About --prefix

I messed around with --prefix for quite a while before I realized what I was
doing. I wanted to install the toolchain to it's "own" directory. What I didn't
realize at first is the difference between the cross-tools (cross-binutils and
cross-gcc) and the cross-built glibc. This led to some confusion about where
the cross-built glibc libraries should go. 

What I settled on is this: let the cross-tools go where they like to go - in /
usr/local. They won't overwrite anything else there. They will put the
MIPS-specific stuff in /usr/local/mips[el]-linux automatically. Then, install
the cross-built glibc libraries into /usr/local/mips[el]-linux, which is where
the cross-build tools expect to find them. 

I guess the summary of all of this is: the --prefix for the cross-build tools
isn't the same as the prefix for the cross-built glibc, and there is no harm in
just letting the cross-build tools go where they want to go, but be careful
with glibc.  

-------------------------------------------------------------------------------

Building

I've written out a fairly complete set of steps, including all the mundane cd
and tar commands, but really the configure command is the most interesting, so
I've separated those commands with some vertical space. 

These steps describe how to build a mipsel cross-toolchain. mipsel stands for
"MIPS-endian-little", or in other words, little-endian MIPS. If you want to
build a big-endian toolchain, modify the steps below by substituting mips-linux
for mipsel-linux. I've done this, but I haven't double-checked this document
for endian issues. It should work with maybe minor adjustments. 

-------------------------------------------------------------------------------

Get binutils, gcc, and glibc

Which versions to get? Currently, it seems that the recipe for building a
modern mipsel cross-toolchain isn't widely known. I've gathered that it is
because of problems with mips binutils. 

Here is the configuration I currently use:

  * binutils-2.13 release
   
  * gcc-3.2 release
   
  * glibc-2.2.5 release plus linuxthreads
   
 

This configuration works well for me. 

Look for toolchain sources at the following locations:

  * binutils: ftp://ftp.gnu.org/gnu/binutils/
   
  * gcc: ftp://ftp.gnu.org/gnu/gcc/
   
  * glibc: ftp://ftp.gnu.org/gnu/glibc/
   
 

Here are some wgets you can copy and paste, courtesy Geoffrey Espin:

wget ftp://ftp.gnu.org/gnu/binutils/binutils-2.13.tar.gz
wget ftp://ftp.gnu.org/gnu/gcc/gcc-3.2.tar.gz
wget ftp://ftp.gnu.org/gnu/glibc/glibc-2.2.5.tar.gz
wget ftp://ftp.gnu.org/gnu/glibc/glibc-linuxthreads-2.2.5.tar.gz
 

When I reference these tar files below, I leave off the version numbers (so I
don't have as much editing to do when I change to a new version of one of the
packages). Please add the version numbers back to the tar file names and to the
unpacked directory names. 

Some stuff that won't work:

  * glibc 2.2.4 - executables failed left and right with "Bus error" and other
    obscure gasps.
   
  * gcc 3.1 - comfigures, builds, and stuff runs, but gcc 3.1 defaults to
    DWARF2 and mips binutils lacks support.
   
 

-------------------------------------------------------------------------------

Build the cross-binutils

As I understand it, cross-binutils prefers not to be given a --prefix (caveat
emptor: my understanding of these matters is clearly meager). However, without
--prefix, the x86 libbfd and libopcodes in /usr/lib get overwritten. That's the
reason for the included --libdir. Steven Langasek suggested it, since it
prevents the conflict and still allows them to be "used by cross-binutils
thanks to the RPATH tag being set appropriately in ELF headers by libtool." 

This ends up putting the cross-binutils in /usr/local. 

tar -xzf binutils.tar.gz
mkdir mipsel-binutils
cd mipsel-binutils

../binutils/configure --target=mipsel-linux \
  --libdir='${exec_prefix}'/mipsel-linux/i386-linux/lib

make
make install
cd ..
 

-------------------------------------------------------------------------------

Build the C cross-compiler

I don't think you can build all of cross-gcc at once; at least I haven't been
able to. One big problem is that you need glibc installed in order to do it,
but you haven't built glibc yet. To get around this, build just the static C
cross-compiler, then you can use that to cross-build glibc, and come back to
the rest of cross-gcc later. 

This ends up putting cross-gcc executables in /usr/local/bin/ and "copies"
(hard links) in /usr/local/mipsel-linux/bin/. The libraries end up in /usr/
local/lib/lib/gcc-lib/mipsel-linux/3.0/. It does however stick a libiberty.a in
/usr/local/lib/ that I'm not entirely comfortable with, but maybe it is just
fine. 

The --with-headers causes configure to make a copy of the headers at the
specified location into /usr/local/mipsel-linux/sys-includes and to run
fixincludes on them. These headers are then used by xgcc during the
cross-building of libgcc.a (which is part of building the static C compiler).
This means that you'll need some MIPS host headers laying around somewhere,
including the linux and asm subdirectories from the Linux kernel. Maybe you
have them from your previous cross-compiler installation. If not, there are
various creative ways of obtaining them, including grabbing them from some MIPS
distribution. There is also the dubious hack of using your hosts's headers
(--with-headers=/usr/include) instead. The key word here is "dubious"; you have
been warned. 

tar -xzf gcc.tar.gz
mkdir mipsel-gcc
cd mipsel-gcc

../gcc/configure --target=mipsel-linux --enable-languages=c \
  --disable-shared --with-headers=/usr/local/mipsel-linux/include

make
make install
cd ..
 

-------------------------------------------------------------------------------

Cross-build glibc

Caution: When installing the cross-built glibc (or other cross-built stuff) if
you don't get it right you can overwrite your host copies of possibly very
critical stuff like libc. Ouch. Best to do cross-building and installing as
non-root for protection. 

You must specify both the "build" and "host" system when cross-building glibc,
since if you just specify "host", glibc assumes the build system is the same as
the host system. 

The right way to do this is to cross-build gcc with the same configuration as
you would for a native build. The main reason for this is that ld.so.1 has the
initial library search path compiled into it. The goal is to get ld.so.1 to
look for libraries in /lib/. If you don't get this right, ld.so.1 will end up
not looking in /lib/ for, say, libc.so.6, which won't allow init=/bin/sh if sh
is dymaically linked against libc.so.6. 

As Jay Carlson pointed out to me, there is (suprise) a trick to this. glibc
sees --prefix=/usr as a special case for Linux. When it sees it, it will sort
things out properly into /lib and /usr/lib, /usr/bin, etc. 

Since glibc configured this way will want to install to "/lib", etc., you have
to use the "install_root" option to cause it to be installed away from your
host's files. After you install glibc out of the way, you can copy the include
and library files to where your cross-build tools expect to find them. 

glibc 2.2.5 doesn't work "out of the box". It requires a small build patch, a
small gmon patch (if you plan to use gprof), and a CFLAGS workaround. I mashed
the patches together into a single patch file and put it at http://www.ltc.com/
~brad/mips/glibc-2.2.5-mips-build-gmon.diff. 

Daniel Jacobowitz <drow@nevyn.them.org> told me about the gmon patch. He also
suggested the -finline-limit workaround below which as I understand it keeps
gcc 3.x from *not* inlining stuff when building ld.so. Without it glibc 2.2.5
ld.so built by gcc 3.x won't work. 

Note: if you mess with --prefix in binutils or gcc, you might end up needing
--with-headers, but I now take this as a sign I've done something screwy. 

tar -xzf glibc.tar.gz
cd glibc
patch -i ../glibc-2.2.5-mips-build-gmon.diff
tar -xzf ../glibc-linuxthreads.tar.gz
cd ..
mkdir mipsel-glibc
cd mipsel-glibc

CFLAGS="-O2 -g -finline-limit=10000" ../glibc/configure --build=i686-linux \
  --host=mipsel-linux --enable-add-ons --prefix=/usr

make
make install install_root=/usr/local/mipsel-linux/glibc
cd ..

cp -a /usr/local/mipsel-linux/glibc/lib/* /usr/local/mipsel-linux/lib/
cp -a /usr/local/mipsel-linux/glibc/usr/include/* /usr/local/mipsel-linux/include/
cp -a /usr/local/mipsel-linux/glibc/usr/lib/* /usr/local/mipsel-linux/lib/
 

Copying the files isn't quite enough though. You also need to edit /usr/local/
mipsel-linux/lib/libc.so (yes, it is a text file suprisingly enough) to point
to the cross-built glibc files so that the cross-build tools know to use the
mipsel libc and not the host's libc, something like: 

GROUP ( /usr/local/mipsel-linux/lib/libc.so.6 
  /usr/local/mipsel-linux/lib/libc_nonshared.a )
 

-------------------------------------------------------------------------------

Build the final C and C++ cross-compilers

Relax... this part is easy. :-) 

cd mipsel-gcc

../gcc/configure --target=mipsel-linux --enable-languages=c,c++

make
make install
 

-------------------------------------------------------------------------------

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7. AGGREGATION WITH INDEPENDENT WORKS

A compilation of the Document or its derivatives with other separate and
independent documents or works, in or on a volume of a storage or distribution
medium, does not as a whole count as a Modified Version of the Document,
provided no compilation copyright is claimed for the compilation. Such a
compilation is called an "aggregate", and this License does not apply to the
other self-contained works thus compiled with the Document , on account of
their being thus compiled, if they are not themselves derivative works of the
Document. If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one quarter of the
entire aggregate, the Document's Cover Texts may be placed on covers that
surround only the Document within the aggregate. Otherwise they must appear on
covers around the whole aggregate.

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8. TRANSLATION

Translation is considered a kind of modification, so you may distribute
translations of the Document under the terms of section 4. Replacing Invariant
Sections with translations requires special permission from their copyright
holders, but you may include translations of some or all Invariant Sections in
addition to the original versions of these Invariant Sections. You may include
a translation of this License provided that you also include the original
English version of this License. In case of a disagreement between the
translation and the original English version of this License, the original
English version will prevail.

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9. TERMINATION

You may not copy, modify, sublicense, or distribute the Document except as
expressly provided for under this License. Any other attempt to copy, modify,
sublicense or distribute the Document is void, and will automatically terminate
your rights under this License. However, parties who have received copies, or
rights, from you under this License will not have their licenses terminated so
long as such parties remain in full compliance.

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10. FUTURE REVISIONS OF THIS LICENSE

The Free Software Foundation may publish new, revised versions of the GNU Free
Documentation License from time to time. Such new versions will be similar in
spirit to the present version, but may differ in detail to address new problems
or concerns. See http://www.gnu.org/copyleft/.

Each version of the License is given a distinguishing version number. If the 
Document specifies that a particular numbered version of this License "or any
later version" applies to it, you have the option of following the terms and
conditions either of that specified version or of any later version that has
been published (not as a draft) by the Free Software Foundation. If the
Document does not specify a version number of this License, you may choose any
version ever published (not as a draft) by the Free Software Foundation.

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Addendum

To use this License in a document you have written, include a copy of the
License in the document and put the following copyright and license notices
just after the title page:

    Copyright © YEAR YOUR NAME.
   
    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 LIST THEIR TITLES, with the Front-Cover Texts being LIST,
    and with the Back-Cover Texts being LIST. A copy of the license is included
    in the section entitled "GNU Free Documentation License".
   
If you have no Invariant Sections, write "with no Invariant Sections" instead
of saying which ones are invariant. If you have no Front-Cover Texts, write "no
Front-Cover Texts" instead of "Front-Cover Texts being LIST"; likewise for 
Back-Cover Texts.

If your document contains nontrivial examples of program code, we recommend
releasing these examples in parallel under your choice of free software
license, such as the GNU General Public License, to permit their use in free
software.