Writing Your First Kernel Module – Part 2

This chapter is the second half of our coverage regarding the Loadable Kernel Module (LKM) framework and how to write kernel modules using it. To get the most out of it, I expect you to complete the previous chapter and try out the code and questions/exercises there before tackling this one.

In this chapter, we will continue from the point where we left off in the previous one. Here, we cover making use of a “better” Makefile for LKMs, cross-compiling a kernel module for the ARM platform (as a typical example), what module stacking is and how to do it, and how to set up and use module parameters. Along the way, among several other things, you will learn about the kernel API/ABI stability (or rather, the lack thereof!), the key differences between writing user-space and kernel code, auto-loading a kernel module at system boot, and security concerns and how they can be addressed. We end with information on the kernel...