Interrupt Handler Overview

An interrupt is a hardware signal from a device to a CPU. An interrupt tells the CPU that the device needs attention and that the CPU should stop any current activity and respond to the device. If the CPU is not performing a task that has higher priority than the priority of the interrupt, then the CPU suspends the current thread. The CPU then invokes the interrupt handler for the device that sent the interrupt signal. The job of the interrupt handler is to service the device and stop the device from interrupting. When the interrupt handler returns, the CPU resumes the work it was doing before the interrupt occurred.

The Solaris DDI/DKI provides interfaces for performing the following tasks:

• Determining interrupt type and registration requirements

• Registering interrupts

• Servicing interrupts

• Masking interrupts

• Getting interrupt pending information

• Getting and setting priority information