Linux Kernel Driver Development

First off: the Linux kernel cannot be taught in 5 days - no way.

Target audience of this course are experienced C programmers who want to get an idea of what it means to be a “Linux kernel hacker”. A quickstart, giving an overview of the mechanisms that define the kernel universe: parallelism, memory management, scheduling, interrupt handling, to name only a few.

With this, and with a great dose of curiosity, you will find yourself enabled to find your own way through the various subsystems inside the Linux kernel.

Course Contents

  • Modules. A module is dynamic shared object that is loaded into a running kernel. We cover its initialization on load, deinitialization at unload, and various other aspects like metadata and module dependencies.

  • Devices. Hardware is represented in software as a device. Device special files (those in /dev/) are used to give userspace an easy to use interface.

  • Synchronization mechanisms. Unlike userpace, where the process abstraction implements the illusion of being alone, the kernel is a massively parallel program (things are further complicated by the presence of hardware interrupts). It is thus vital to know how to protect oneself against any kind of race condition.

  • Communication mechanisms. Waiting for an event to occur - while not consuming any CPU time - is one of the most important responsibilities of any operating system.

  • Interrupt handling. Hardware interrupts are something that an operating system cannot do without. Linux has a number of ways to deal with interrupts.

  • Direct memory access (DMA). Efficient communication between hardware devices and (processes running on) the CPU requires devices to be able to access CPU memory. Devices access main memory in different ways; we give an overview of the APIs that are available to implement each.

  • PCI. PCI hardware is commonplace in today’s computers. We explain how the PCI subsystem of the Linux kernel works.

Sample Project

An exercise project accompanies the course, giving the audience a chance to get in touch with the mechanisms as they are covered.

See here for a trainer-centric view of what’s to be done.

Prerequisites

Attendees are expected to be fluent in C.