Evaluation Linux

The considerations from the design will be evaluated within this chapter. As the decision against the Yocto Project and Buildroot was already made, those two are no longer evaluated and a solution to build the Linux kernel with low configuration effort has to be found.

Cross Target Support

Linux supports cross compilation and can therefore be compiled with a cross toolchain.

Build Process

Due to keeping the possibility to build the kernel locally, emerging the kernel sources with OS dependent tools (e.g. emerge with Gentoo) is not a viable solution. As already mentioned in the u-boot evaluation, keeping the sources within the Linux repository will lead to a lot of overhead when the same Linux versions should be build for different platforms. The same solution as already described in the u-boot evaluation will be used.

Each Linux version has a branch, which contains a script that downloads the specific sources. Each platform has a branch for each Linux version that should be build. This branch contains a script which executes the download script from the Linux version branch.

Structure

Build Steps

With the now evaluated build process, the build steps can be redefined.

  1. Checkout platform branch for Linux version X
  2. Checkout Linux version X branch
  3. Call build script build from platform branch
    • set necessary build parameters
  4. Call build script build from Linux version X branch
    • download sources
    • if provided apply patches
    • build Linux
    • create archive

Build Tools

These tools are needed to successfully iterate through the build steps.