Linux Kernel

Linux Kernel Introduction

• System and kernel overview

• Kernel code specifics

• Kernel subsystems

• History and versioning scheme

• Understanding the development process

• Specific legal issues

• Kernel user interface

Kernel Sources

• Getting the sources

• Using the patch command

• Structure of source files

• Kernel source code browsers

Compiling

• Kernel configuration

• Useful settings for embedded systems

• Compiling

• Generated files

• Make commands for configuring, compiling or installing a kernel

Booting

• Linux system booting overview

• The boot-loader’s job

• Review of Linux boot-loaders

• U-boot details

• Linux kernel booting

• Advantages of initramfs over initrd

• Booting parameters

• NFS boot example

• System startup

Cross-compiling

• Kernel cross-compiling setup

• Ready-made configuration files for specific architectures & boards

• Cross-compiling

Basic Driver Development

• Linux device drivers

• A simple module

• Programming constraints

• Loading, unloading modules

• Module parameters and dependencies

• Adding sources to the kernel tree

Linux Memory Management

• Linux memory management

• Physical and virtual (kernel and user) address spaces

• Linux memory management implementation

• Allocating with kmalloc, by pages and with vmalloc

I/O Memory

• I/O register and memory range registration

• I/O register and memory access

• Read / write memory barriers

Character Drivers

• Device numbers

• Getting free device numbers

• File operations

• Character driver registration

Kernel Debugging

• Using printk, /proc or /sys

• Debugfs

• Using an ioctl interface, gdb and kgdb

Processes and scheduling

• Process life

• Timer frequency

• Priorities and timeslices

• Sleeping and waking up API

Interrupts

• Waiting for the availability of resources

• Interrupt handler registration

• Scheduling deferred work

Concurrency management

• Managing concurrent access to resources: mutexes, spinlocks

• Atomic operations

Advice and resources

• Getting help and contributions

• Bug report and patch submission to Linux developers

• References: websites, books & international conferences

Kernel boot-up details

• Detailed description of the kernel boot-up process, from execution by the boot-loader to the execution of the first userspace program

• Initcalls: how to register your own initialization routines?

Introduction to BSP development

• Board Support Packages (BSP)

• Porting U-boot and the Linux kernel

• Creating board dependent code

• Studying code for an ARM board

Introduction to power management

• Supporting frequency scaling

• CPU and board specific power management

• Power management in device drivers

• Control from user space

• Saving power in the idle loop

• Studying power management implementations in the Linux kernel

Introduction to Linux Real-Time Programming

• Understanding the sources of latency in standard Linux

• Soft real-time solutions for Linux: improvements in Linux 2.6

• Use the latest RT preempt patches for mainstream Linux

• Real-time kernel debugging

• Measuring and analyzing latency

• Hard real-time solutions for Linux

• RTLinux issues, the RTAI and Xenomai projects

• Comparing with RT preempt patches

• Real-time offerings from commercial Linux vendors: MontaVista, TimeSys, Wind River, LynuxWorks etc

C library and cross-compiling tool-chain

• Choosing the target C library

• Ready to use cross-compiling tool-chains

• Building a cross-compiling tool-chain with automated tools

• Installing cross-compiled libraries in the root filesystem

Embedded system development tools

• Commercial toolsets and distributions

• Community toolsets (focus on Buildroot & Scratchbox)

• How to find existing Free Software for a particular need