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

Converting mainline Linux into an RTOS

Mainline or vanilla Linux (the kernel you download from https://kernel.org) is decidedly not a Real-Time Operating System (RTOS); it's a General Purpose Operating System (GPOS; as is Windows, macOS, Unix). In an RTOS, where hard real-time characteristics come into play, not only must the software obtain the correct result, there are deadlines associated with doing so; it must guarantee it meets these deadlines, every single time. The mainline Linux OS, though not an RTOS, does a tremendous job: it easily qualifies as being a soft real-time OS (one where deadlines are met most of the time). Nevertheless, true hard real-time domains (for example, military operations, many types of transport, robotics, telecom, factory floor automation, stock exchanges, medical electronics, and so on) require an RTOS.

Another key point in this context is that of determinism: an oft missed point regarding...