Summary

In this chapter, you first learned about the Linux kernel’s release (or version) nomenclature (remember, Linux kernel releases are time- and not feature-based!), the various types of Linux kernels (-next trees, -rc/mainline trees, stable, LTS, SLTS, distributions, custom embedded), and the basic kernel development workflow. You then learned how to obtain for yourself a Linux kernel source tree and how to extract the compressed kernel source tree to disk. Along the way, you even got a quick 10,000-foot view of the kernel source tree so that its layout is clearer.

After that, critically, you learned how to approach the kernel configuration step and perform it – a key step in the kernel build process! Furthermore, you learned how to customize the kernel menu, adding your own entries to it, and a bit about the Kconfig/Kbuild system and the associated Kconfig files it uses, among others.

Knowing how to fetch and configure the Linux kernel is a useful skill to possess. We have just begun this long and exciting journey. You will realize that with more experience and knowledge of kernel internals, drivers, and the target system hardware, your ability to fine-tune the kernel to your project’s purpose will only get better.

We’re halfway to building a custom kernel; I suggest you digest this material, try out the steps in this chapter in a hands-on fashion, work on the questions/exercises, and browse through the Further reading section. Then, in the next chapter, let’s actually build the 6.1.25 kernel and verify it!