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)
1
Section 1: The Basics
6
Writing Your First Kernel Module - LKMs Part 2
7
Section 2: Understanding and Working with the Kernel
10
Kernel Memory Allocation for Module Authors - Part 1
11
Kernel Memory Allocation for Module Authors - Part 2
14
Section 3: Delving Deeper
17
About Packt

Understanding process and interrupt contexts

In Chapter 4, Writing Your First Kernel Module – LKMs, Part 1, we presented a brief section entitled Kernel architecture I (if you haven't read it yet, I suggest you do so before continuing). We will now expand on this discussion.

It's critical to understand that most modern OSes are monolithic in design. The word monolithic literally means a single large piece of stone. We shall defer a little later to how exactly this applies to our favorite OS! For now, we understand monolithic as meaning this: when a process or thread issues a system call, it switches to (privileged) kernel mode and executes kernel code, and possibly works on kernel data. Yes, there is no kernel or kernel thread executing code on its behalf; the process (or thread) itself executes kernel code. Thus, we say that kernel code executes within the context of a user space process or thread – we call this the ...