Book Image

Linux Kernel Programming

By : Kaiwan N. Billimoria
Book Image

Linux Kernel Programming

By: Kaiwan N. Billimoria

Overview of this book

Linux Kernel Programming is a comprehensive introduction for those new to Linux kernel and module development. This easy-to-follow guide will have you up and running with writing kernel code in next-to-no time. This book uses the latest 5.4 Long-Term Support (LTS) Linux kernel, which will be maintained from November 2019 through to December 2025. By working with the 5.4 LTS kernel throughout the book, you can be confident that your knowledge will continue to be valid for years to come. You’ll start the journey by learning how to build the kernel from the source. Next, you’ll write your first kernel module using the powerful Loadable Kernel Module (LKM) framework. The following chapters will cover key kernel internals topics including Linux kernel architecture, memory management, and CPU scheduling. During the course of this book, you’ll delve into the fairly complex topic of concurrency within the kernel, understand the issues it can cause, and learn how they can be addressed with various locking technologies (mutexes, spinlocks, atomic, and refcount operators). You’ll also benefit from more advanced material on cache effects, a primer on lock-free techniques within the kernel, deadlock avoidance (with lockdep), and kernel lock debugging techniques. By the end of this kernel book, you’ll have a detailed understanding of the fundamentals of writing Linux kernel module code for real-world projects and products.
Table of Contents (19 chapters)
Section 1: The Basics
Writing Your First Kernel Module - LKMs Part 2
Section 2: Understanding and Working with the Kernel
Kernel Memory Allocation for Module Authors - Part 1
Kernel Memory Allocation for Module Authors - Part 2
Section 3: Delving Deeper
About Packt

Using the RMW atomic operators

A more advanced set of atomic operators called the RMW APIs is available as well. Among its many uses (we show a list in the coming section) is that of performing atomic RMW operations on bits, in other words, performing bitwise operations atomically (safely, indivisibly). As a device driver author operating upon device or peripheral registers, this is indeed something you will find yourself using.

The material in this section assumes you have at least a base understanding of accessing peripheral device (chip) memory and registers; we have covered this in detail in Chapter 13Working with Hardware I/O Memory. Please ensure you understand it before moving further. 

Very often, you'll need to perform bit operations (with the bitwise AND & and bitwise OR | being the most commonplace operators) on registers; this is done to modify its value, setting and/or clearing some bits within it. The thing is, merely...