What you'll learn:
- Interrupts and Bottom Halves
This course provides a comprehensive look at how the Linux kernel handles interrupts and exceptions. You will learn about the different types of interrupts, such as Level Triggered and Edge Triggered, as well as Traps and Faults. The curriculum covers the hardware components responsible for interrupt management, including the Programmable Interrupt Controller and the Advanced Programmable Interrupt Controller (APIC). You will also learn how to use the CPUID instruction to find information about your x86 CPU.
The course will guide you through the complete interrupt handling process, from the initial Interrupt Request to how the CPU uses the Interrupt Descriptor Table (IDT) to locate the correct handler. You will also explore practical topics like interrupt sharing and IRQ Affinity in the Linux kernel. The course includes hands-on experience, such as writing a Linux driver for devices and creating a simple keylogger to log typed characters. You will also learn about enabling and disabling interrupts and why you should avoid adding sleep or delays in an interrupt handler.
A significant portion of the course is dedicated to the concept of Top and Bottom Halves, which are used for deferred work. You will learn the distinctions between softirqs, tasklets, and workqueues and when to use each for optimal performance. The course also teaches you how to use various files in the /proc filesystem and commands like watch and dmesg to analyze interrupt behavior and debug issues, providing a practical foundation for working with kernel-level programming.
