Book Image

Embedded Linux Development Using Yocto Project Cookbook - Second Edition

By : Alex Gonzalez
Book Image

Embedded Linux Development Using Yocto Project Cookbook - Second Edition

By: Alex Gonzalez

Overview of this book

The Yocto Project has become the de facto distribution build framework for reliable and robust embedded systems with a reduced time to market.You'll get started by working on a build system where you set up Yocto, create a build directory, and learn how to debug it. Then, you'll explore everything about the BSP layer, from creating a custom layer to debugging device tree issues. In addition to this, you’ll learn how to add a new software layer, packages, data, scripts, and configuration files to your system. You will then cover topics based on application development, such as using the Software Development Kit and how to use the Yocto project in various development environments. Toward the end, you will learn how to debug, trace, and profile a running system. This second edition has been updated to include new content based on the latest Yocto release.
Table of Contents (13 chapters)
Title Page
Packt Upsell

Describing Linux's build system

The Linux kernel is a monolithic kernel and, as such, shares the same address space. Although it has the ability to load modules at runtime, the kernel must contain all the symbols the module uses at compilation time. Once the module is loaded, it will share the kernel's address space too.

The kernel build system (kbuild), uses conditional compilation to decide which parts of the kernel are compiled. kbuild is independent of the Yocto build system.

In this recipe, we will explain how kbuild works.

How to do it...

The kernel kbuild system reads its configuration at build time from a .config text file in the kernel root directory. This is referred to as the kernel configuration file. It is a text file where each line contains a single configuration variable that starts with the CONFIG_ prefix.

There are multiple ways to modify a kernel configuration file:

  1. Manually editing the .config file, although this is not recommended.
  2. Using one of the user interfaces the kernel...