Minimum CSR requirements to run Linux

Question

What are the minimum CSR required to run Linux on a RISC-V processor?
The privileged ISA spec does not seem to clarify this point.

Answer 1

A minimum requirement for an operating system would be to be able to service exceptions: external interrupts & software exceptions.

The following two answers may shed some light on this, though will not answer specifically the question of the requirements for linux.  I don't know the additional requirements of linux, but we would be thinking about clock/timer, virtual memory, others?

• RISC-V Interrupt Handling Flow

• Risc-V: Minimum CSR requirements for simple RV32I implementation capable of leveraging GCC