System call vs Interrupt contexts

Question

System calls are implemented using software interrupts(interrupt vector 128). In roberts love book "Linux Kernel Development" its written that interrupt handle happens at interrupt context. Its also written that system call runs at process context, but system call handle is in fact an " interrupt handle" so why its in different context?

Answer 1

You're getting the implementation of your platform mixed up with the design of the Linux Kernel.

When you're talking about the Linux Kernel, the interrupt context is where code runs 'on its own' with no process attached to it - commonly used for handling interrupts from devices. Process context is as a result of a system call from a userland process and code running in it is 'attached' to a process.

When you're talking about the platform implementation, an interrupt context could simply mean that the processor is in a interrupt handler mode of some sort. I don't know enough about your platform to provide anything specific.