Thanks Peter that was most helpful. Aside from running out of space on my undersized virtual box and a bit of a wait, everything went pretty painlessly following those instructions. For the benefit of any future readers/sake of completeness, to get the cross-compiling etc. under way I installed the following packages from the command line (other dependent packages installed for free of course) gcc gcc-arm-linux-gnu hmaccalc m4 Andrew On 8 July 2015 at 22:48, Peter Robinson <pbrobinson@xxxxxxxxx> wrote: > 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
