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

Debugging the Linux kernel and modules

We will highlight some of the most common methods employed by kernel developers to debug kernel issues.

How to do it...

Above all, debugging the Linux kernel remains a manual process, and the most important developer tool is the ability to print debug messages.

The kernel uses the printk function, which is very similar syntactically to the printf function call from standard C libraries, with the addition of an optional log level. The allowed formats are documented in the kernel source under Documentation/printk-formats.txt.

The printk functionality needs to be compiled into the kernel with the CONFIG_PRINTK configuration variable. You can also configure the Linux kernel to prepend a precise timestamp to every message with the CONFIG_PRINTK_TIME configuration variable, or even better, with the printk.time kernel command-line argument or through the sysfs under /sys/module/printk/parameters.


The sysfs is a pseudo filesystem where the Linux kernel exposes...