BBB - Building the Linux Kernel

That's excellent, shabaz!  I'll follow along on one of my Gentoo boxes and add any Gentoo-specific lines to the document.  I don't expect many differences.

First of all I need to know the provinence of RHEL's ARM gcc variant.  Is it CodeSourcery, or is RedHat validating their own ARM compiler releases?  Gentoo has the following 3 ARM compiler  packages available in Portage, so if yours isn't one of these, Gentoo users will have to install a ggc-arm manually from some repo outside of Portage, not with the package manager:

* dev-embedded/sgpp-lite-arm-eabi-bin
     Available versions:  (2010.09.51) ~2010.09.51
     Homepage:            http://www.codesourcery.com/sgpp/lite/arm
     Description:         regular, validated releases of the GNU Toolchain for arm processors by CodeSourcery

* dev-embedded/sgpp-lite-arm-linux-bin
     Available versions:  (2010.09.50) ~2010.09.50
     Homepage:            http://www.codesourcery.com/sgpp/lite/arm
     Description:         regular, validated releases of the GNU Toolchain for arm processors by CodeSourcery

* dev-embedded/sgpp-lite-arm-uclinux-bin
     Available versions:  (2010.09.58) ~2010.09.58
     Homepage:            http://www.codesourcery.com/sgpp/lite/arm
     Description:         regular, validated releases of the GNU Toolchain for arm processors by CodeSourcery

PS. I sure hope the "2010" isn't a year, otherwise these ARM releases in Portage are clearly prehistoric.   Gentoo's own ARM  installation procedure doesn't use the above, which hints that those 3 packages are a historical relic.

Instead, Gentoo provides these instructions, specifically for BeagleBone, with cross tools installed using crossdev.

Regarding the kernel, the above link advises to get the kernel using:

git clone git://arago-project.org/git/projects/linux-am33x.git

Is that kernel similar to yours in respect of version and patches?  Reading about the Arago Project, I'm a bit worried about kernel biodiversity creeping in here.

If your ARM compiler is maintained and validated by RedHat themselves, I suspect that for full compatibility with your steps, Gentoo users will have to grab your source RPM and unpack it directly.  If so, it would help if you could identify the actual package filepath that your commands install.

[Fixed the almighty cocktail of compiler and kernel topics which made this post barely comprehensible.]

Hi Morgaine,

Morgaine Dinova wrote:

I'll follow along on one of my Gentoo boxes and add any Gentoo-specific lines to the document.  I don't expect many differences.

That's great! I hope the steps make sense, and it will be great to have them refined. I used RHEL for my Linux server, mainly because I'm not familiar with other variants, and the toolchain I used was one that was available pre-compiled via yum. But I did try CodeSourcery originally, and although it compiled the kernel, after TFTP'ing, it didn't work for me, but later I realized I was issuing the wrong u-boot parameters, so it's quite likely CodeSourcery is fine.  The CodeSourcery site (i.e. the Mentor Graphics site) did have much more recent toolchain dates, I had downloaded from there. In fact I've still got those steps because I was writing it as I went, I've pasted below. When it didn't work for me, I moved to the one via yum, and didn't get round to re-checking with CodeSourcery after I'd discovered the u-boot mistake I was making.

From that arago-project, I had only downloaded some blob. The kernel was downloaded using git clone git://github.com/beagleboard/kernel.git

That instruction was based on some websites that had instructions for Debian, but it seemed to work fine on my RHEL VM. I wish I knew how to get the exact tag for the releases though, because if I'm building the head of 3.8, then I'll never be sure what others may have checked-in I guess :-(

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

The compiler is Sourcery CodeBench Lite Edition for ARM GNU/Linux (2013.05-24 version) from Mentor Graphics’ website

http://www.mentor.com/embedded-software/sourcery-tools/sourcery-codebench/lite/?cmpid=7108&lite=arm&target_os=GNU%2FLinux&target_arch=ARM&returnURL=https%253A%252F%252Fsourcery.mentor.com%252FGNUToolchain%252Fsubscription3057%253Flite%253Darm%2526cmpid%253D7108

Note: the current toolchains from the Angstrom site and from TI’s SDK both had issues building the kernel.

From that Mentor Graphics link, use the IA32 GNU/Linux TAR file rather than the installer

The downloaded file was put in the toolchain folder and extracted (it created an arm-2013.05 folder). The folder /home/username/develop/toolchain/arm-2013.05/bin is important, it contains the compile tools. The PATH environment variable needs to be updated to prepend this: (assuming bash shell)

Somehow I managed to conflate compiler and kernel provinence in my reply, so the combined post makes no sense at all.   I'll fix it in a bit and separate the two parts.

Meanwhile, I'm trying to aim for exact replication of your compiler and kernel, ie. specifically not doing your suggestion of using apt-get on a Debian/Ubuntu system for example, as that would produce a different end result.  Likewise, I'm trying to avoid installing the cross-compiler with Gentoo's "crossdev -S armv7a-hardfloat-linux-gnueabi" command, as that would likely be different.  (I might install it just to see where it comes from though.)

To confirm, when you did a "yum install gcc-arm-linux-gnu", that installed Sourcery CodeBench Lite Edition for ARM GNU/Linux (2013.05-24 version) from Mentor Graphics’ website?

The kernel part is clear, you got that from git://github.com/beagleboard/kernel.git

Hi Morgaine,

No, it was not the CodeSourcery version that got installed when I did the yum command, as far as I know.

This is the information that gcc-v and yum info reports (my VM was 32-bit unfortunately, I had the wrong ISO and didn't re-download it):

$ gcc -v

Using built-in specs.

Target: i686-redhat-linux

Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --with-bugurl=http://bugzilla.redhat.com/bugzilla --enable-bootstrap --enable-shared --enable-threads=posix --enable-checking=release --with-system-zlib --enable-__cxa_atexit --disable-libunwind-exceptions --enable-gnu-unique-object --enable-languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --disable-dssi --with-java-home=/usr/lib/jvm/java-1.5.0-gcj-1.5.0.0/jre --enable-libgcj-multifile --enable-java-maintainer-mode --with-ecj-jar=/usr/share/java/eclipse-ecj.jar --disable-libjava-multilib --with-ppl --with-cloog --with-tune=generic --with-arch=i686 --build=i686-redhat-linux

Thread model: posix

gcc version 4.4.5 20110214 (Red Hat 4.4.5-6) (GCC)

$

# yum info gcc-arm-linux-gnu

Loaded plugins: refresh-packagekit, security

epel/metalink                                            |  19 kB     00:00    

epel                                                     | 4.2 kB     00:00    

epel/primary_db                                          | 4.4 MB     00:02    

sl                                                       | 2.5 kB     00:00    

sl-security                                              | 2.6 kB     00:00    

Installed Packages

Name        : gcc-arm-linux-gnu

Arch        : i686

Version     : 4.7.2

Release     : 2.aa.20121114svn.el6.1

Size        : 25 M

Repo        : installed

From repo   : epel

Summary     : Cross-build binary utilities for arm-linux-gnu

URL         : http://gcc.gnu.org

License     : GPLv3+ and GPLv3+ with exceptions and GPLv2+ with exceptions and

            : LGPLv2+ and BSD

Description : Cross-build GNU C compiler.

            :

            : Only building kernels is currently supported.  Support for

            : cross-building user space programs is not currently provided as

            : that would massively multiply the number of packages.

#

However, some URLs were mentioning using different compilers such as gcc-4.7-arm-linux-gnueabi-base, and Vlad compiled using this one (he was going to try to TFTP it to his BBB last night, he is yet to report if it worked for him): apt-get install gcc-arm-linux-gnueabi

So, it looks like this URL is for the compiler:

http://pkgs.org/centos-6-rhel-6/epel-x86_64/gcc-arm-linux-gnu-4.7.2-2.aa.20121114svn.el6.1.x86_64.rpm.html (assuming RPM can work with Gentoo).

Ah, ok.  So, it seems the gcc-arm biodiversity explosion has already happened, and everyone will be using different versions, hehe.

No worries, I might as well use Gentoo's crossdev then.  Hopefully we won't hit specific compiler version dependencies.

Ah, cool. I'll kick off a build using CodeSourcery too, so we can confirm if it really works or not. You're right, it would be nice for us all to use a consistent compiler. I'll know in an hour to two!

Ah, cool. I'll kick off a build using CodeSourcery too, so we can confirm if it really works or not. You're right, it would be nice for us all to use a consistent compiler. I'll know in an hour to two!