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

Visualizing with trace-cmd

Modern Linux kernels (from 2.6.27) embed a very powerful tracing engine called Ftrace. Ftrace is the rough kernel equivalent of the user space strace(1) utility, but that would be short-selling it! Ftrace allows the sysad (or developer, tester, or anyone with root privileges really) to literally look under the hood, seeing every single function being executed in kernel space, who (which thread) executed it, how long it ran for, what APIs it invoked, with interrupts (hard and soft) included as they occur, various types of latency measurements, and more. You can use Ftrace to learn about how system utilities, applications, and the kernel actually work, as well as to perform deep tracing at the level of the OS.

Here, in this book, we refrain from delving into the depths of raw Ftrace usage (as it deviates from the subject at hand); instead, it is just quicker and easier to use a user space wrapper over Ftrace, a more convenient interface to it, called...