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

Using the Linux man pages

You must have noticed the convention followed in most Linux/Unix literature:

  • The suffixing of user commands with (1) – for example, gcc(1) or gcc.1
  • System calls with (2) – for example, fork(2) or fork().2
  • Library APIs with (3) – for example, pthread_create(3) or pthread_create().3

As you are no doubt aware, the number in parentheses (or after the period) denotes the section of the manual (the man pages) that the command/API in question belongs to. A quick check with man(1), via the man man command (that's why we love Unix/Linux!) reveals the sections of the Unix/Linux manual:

$ man man
[...]
A section, if provided, will direct man to look only in that section of
the manual. [...]

The table below shows the section numbers of the manual followed by the types of pages they contain.

1 Executable programs or shell commands
2 System calls (functions provided by the kernel)
3 Library calls (functions within program libraries)
4 Special files (usually found in /dev)
5 File formats and conventions eg /etc/passwd
6 Games
7 Miscellaneous (including macro packages and conventions), e.g.
man(7), groff(7)
8 System administration commands (usually only for root)
9 Kernel routines [Non standard]
[...]

So, for example, to look up the man page on the stat(2) system call, you would use the following:

man 2 stat # (or: man stat.2)

At times (quite often, in fact), the man pages are simply too detailed to warrant reading through when a quick answer is all that's required. Enter the tldr project – read on!