| gcc/glibc cross toolchains for embedded development |
by Dan Kegel (Aug. 28, 2003)
Building a gcc / glibc cross-toolchain for use in embedded systems development used to be a scary prospect, requiring iron will, days if not weeks of effort, lots of Unix and Gnu lore, and sometimes willingness to take dodgy shortcuts. This is a problem not only for individual users, but also for the gcc project as a whole, since the gcc team relies on users to test upcoming releases of gcc, and the difficulty of building the toolchain for embedded targets restricted the number of people able to help with the testing.
At Ixia, I had been maintaining a toolchain by starting with a commercial free embedded linux toolchain, and overlaying it with newer versions compiled from scratch as needed to fix problems. This became harder to maintain as time went on.
This article discusses one possible approach to solving this problem.
Enhancing the community build script
After some months of frustration, it became clear we needed an easy way to build and test gcc/glibc cross-toolchains from scratch. Looking around, I realized that Bill Gatliff's crossgcc FAQ and build script, what most of the community used to build cross-compilers, was almost what I needed, so I rolled up my sleeves and: - made darn sure it worked properly for ppc and gcc-2.95
- removed newlib support so I could focus on glibc more easily
- updated it to handle gcc-3.2.x, gcc-3.3.x, and gcc-3.4.x, since I wasn't sure which of those I would need
- enhanced it to automatically download the source tarballs and apply the minimal set of patches needed to successfully build
- enhanced it to support all CPU types supported by glibc, since that was easy and was a good test of the script
- added support for running the gcc and glibc regression test suites, since at Ixia we need regression tests for everything we ship
- documented how to run dejagnu regression tests remotely, since that's how to test gcc on a small embedded platform, and the dejanu documentation is misleading and incomplete
- documented how to set up a chroot jail that allows remote login, since a chroot jail is the easiest way to test alternate versions of glibc, and there weren't any good howto's on the subject
- added support for building userspace (for now, just busybox) with the new toolchain (see --builduserspace option to all.sh) so you can test even if you don't have userspace apps compatible with the new toolchain
Results
I call my updated script and associated patches 'crosstool'. It's fairly easy to use and can be run unattended as part of an automatic build process, and should go a long way towards making it easier for the average developer to get started with gcc cross-compilers and help test new releases of gcc.
The gcc-3.3.1/glibc-2.3.2 toolchains it generates for ppc405 and ppc750 pass nearly all gcc, glibc, and binutils regression tests.
The gcc-3.3.1/glibc-2.3.2 toolchain it generates for sh4 fails a noticable number of the glibc tests, but is far enough along that you can try it, if you're willing to look into the problems.
The gcc-3.4-20030813 snapshot toolchains for these processors fail with several internal compiler errors building the regression tests, which is not suprising given that gcc-3.4 is still in stage 2.
Downloads
About the author
 Dan Kegel is a software engineer currently helping develop network test equipment at Ixia. He has been programming since 1978, and mentoring intern programmers since 1994. He served on the JSR-51 committee which helped add nonblocking I/O and file locking to the Java platform. His web site "The C10K Problem" is well-known among a small circle of internet server programmers, and his essay "The Case for Linux in Universities" has been translated into Spanish, Hindi, and Telugu. He maintains lalugs.org as a service to the Los Angeles Linux community. He thanks his wife Liz Fuller for her support and patience during his periodic save-the-world quests, Ixia for supporting this work, Bill Gatliff for the original script, and Kaz Kojima and Daniel Jacobowitz for supplying patches on the spot to solve various problems.
Last Change 26 Aug 2003. The latest copy of this document can be found at kegel.com/crosstool. Copyright © 2003 Dan Kegel, with portions copyright by Ixia, 2003. All rights reserved. Reproduced by LinuxDevices.com with permission of the author. Crosstool is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
(Click here for further information)
|
|
|
7 Advantages of D2D Backup
For decades, tape has been the backup medium of choice. But, now, disk-to-disk (D2D) backup is gaining in favor. Learn why you should make the move in this whitepaper.
4 Legal Reasons to Control Internet Access
The Internet is obviously a valuable resource for many organizations. However, many are exposed to legal liability concerns because they fail to control Internet access. Learn if you're safe in this white paper.
Rapidly Resolve J2EE Application Problems
Whether you are in the process of building J2EE applications or have J2EE applications already running in production, you must ensure that they deliver the expected ROI. Learn how in this white paper.
Load Testing 2.0 for Web 2.0
There are many unknowns in stress testing Web 2.0 applications. Find out how to test the performance of Web 2.0 in this white paper.
Build Better Games Online
For the game infrastructure providers, life is complex. Making money from games has become more complicated. Why? Find out in this white paper.
Building a Virtual Infrastructure from Servers to Storage
This white paper discusses the virtual storage solutions that reduce cost, increase storage utilization, and address the challenges of backing up and restoring Server environments.
Gaining Faster Wireless Connections with WiMAX
Welcome to what is quickly becoming the hyperconnected world where anything that would benefit from being connected to the network will be connected. Learn more in this white paper.
Is Your Desktop a Security Threat?
The new wave of sophisticated crimeware not only targets specific companies, but also targets desktops and laptops as backdoor entryways into those business’ operations and resources. Learn how to stay safe in this white paper.
Increasing SAN Reliability by 100 Percent
Storage area networks (SAN) are a strong part of storage plans. Learn how to increase your reliability and uptime by 100 percent in this case study.
|
|
|
|
|
news feed