Hi Andrew, > I am a newbie with kernel matters so I apologize in advance for what is a > newbie type setup question. My feeling is that if I send this query to the > more general Arm Fedora forum, the mere mention of kernel will provoke > glazed eyes :-) Unlikely, I do it all the time, happy to help ;-) > The background is that I have an OEM board based on a TI AM3352 OMAP family > SoC looking somewhat like a Beaglebone black. Recently I've been exploring > getting this running under Fedora. In order to get it working I've cobbled > together the F22 minimal image along with a device tree blob created by a > colleague for this board, and a customised MLO/u-boot. > > My next task is to look through and understand the arm kernel sources, > customize various aspects of the kernel config for my board and re-build. > > It seems that instructions are here: > > https://fedoraproject.org/wiki/Building_a_custom_kernel > > However, I want to cross compile on a host system. To ease this process I > have set up a Fedora x86 box, also running f22, which is going to be the > host build machine. > > I decided I should build from source rpm and was following the wiki > instructions(rpmdev-setuptree etc.) up to the point here... The easiest way to do this is: Install the Fedora packaging tools: "dnf install fedora-packager" Clone the kernel package source and switch the F-22 branch: "fedpkg clone -a kernel" cd kernel "fedpkg switch-branch f22" The kernel config for the am33xx devices like the BBB is in a file called config-armv7. It's a bit confusing to get started but basically there's inheritance on the config files config-generic -> config-arm-generic -> config-armv7-generic -> config-armv7 Most of the bits related to the am33xx are in a section titled "# AM33xx/43xx" Adjust the config as you like. Once you've done that run "fedpkg prep" which will make sure all your config changes aren't missing anything. Then do "fedpkg srpm" to create a .src.rpm Then to cross compile run the following command: rpmbuild --rebuild --target armv7hl --with=cross --without=perf --without=tools --without=debuginfo --without=pae --define="_arch arm" --define="_build_arch arm" --define="__strip /usr/bin/arm-linux-gnu-strip" kernel-version.src.rpm That will builder you the kernel and modules. You want to leave out tools/perf as they don't tend to cross compile well but it's unlikely they'll differ much from the ones we already ship, I've never had an issue with those. > At this point I'd like to actually have a target of arm7l for my target but > entering this gets me an unknown target error (possibly not surprising > given the build machine/target architecture difference!). Use the command above and you should be good. > My build machine does have a suitable linaro Arm compiler in place. It > occurs to me that I need a different kernel spec and to indicate to my > build system to use my compiler. Hopefully this can be achieved via some > slightly modified step from that given in the wiki page? Or should I be > tackling this in a completely different way? The above command will prompt you to install the Fedora cross compiler toolchain, I would recommend using that, it works fine for am33xx and other ARMv7 devices, YMMV with Linaro toolchain. Peter _______________________________________________ kernel mailing list kernel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/kernel
