You're reading from Mastering Embedded Linux Programming - Third Edition

Product type Book

Published in May 2021

Publisher Packt

ISBN-13 9781789530384

Pages 758 pages

Edition 3rd Edition

Languages

Concepts

Embedded Systems

Authors (2):

Frank Vasquez

Chris Simmonds

View More author details

Table of Contents (27) Chapters

Preface

1. Section 1: Elements of Embedded Linux

2. Chapter 1: Starting Out

3. Chapter 2: Learning about Toolchains

4. Chapter 3: All about Bootloaders

5. Chapter 4: Configuring and Building the Kernel

6. Chapter 5: Building a Root Filesystem

7. Chapter 6: Selecting a Build System

8. Chapter 7: Developing with Yocto

9. Chapter 8: Yocto Under the Hood

10. Section 2: System Architecture and Design Decisions

11. Chapter 9: Creating a Storage Strategy

12. Chapter 10: Updating Software in the Field

13. Chapter 11: Interfacing with Device Drivers

14. Chapter 12: Prototyping with Breakout Boards

15. Chapter 13: Starting Up – The init Program

16. Chapter 14: Starting with BusyBox runit

17. Chapter 15: Managing Power

18. Section 3: Writing Embedded Applications

19. Chapter 16: Packaging Python

20. Chapter 17: Learning about Processes and Threads

21. Chapter 18: Managing Memory

22. Section 4: Debugging and Optimizing Performance

23. Chapter 19: Debugging with GDB

24. Chapter 20: Profiling and Tracing

25. Chapter 21: Real-Time Programming

26. Other Books You May Enjoy

Moving from the bootloader to a kernel

When the bootloader passes control to the kernel, it has to pass some basic information, which includes the following:

The machine number, which is used on PowerPC and Arm platforms without support for a device tree, to identify the type of the SoC.
Basic details of the hardware that's been detected so far, including (at the very least) the size and location of the physical RAM and the CPU's clock speed.
The kernel command line.
Optionally, the location and size of a device tree binary.
Optionally, the location and size of an initial RAM disk, called the initial RAM file system (initramfs).

The kernel command line is a plain ASCII string that controls the behavior of Linux by giving, for example, the name of the device that contains the root filesystem. We will look at the details of this in the next chapter. It is common to provide the root filesystem as a RAM disk, in which case it is the responsibility...