add tests for the SPMP extension

[ybc-alkaid]

This PR introduces basic tests for the RISC-V S-level Physical Memory Protection (SPMP) extension.

Here is the pointer to the SPMP specification:
riscv/riscv-isa-manual#2573

Here is a pre-built PDF of SPMP:
https://github.com/riscv/riscv-spmp/blob/main/rv-spmp-spec.pdf

[aswaterman]

Thanks, @ybc-alkaid. I see these are not included in isa/Makefile, presumably because they don't yet work on upstream Spike.

My preference is to add them to isa/Makefile, but wait to merge this PR until Spike can execute them.

[ybc-alkaid]

Hi @aswaterman,
The tests have been added to isa/rv64si/Makefrag and isa/rv32si/Makefrag, so they will be included in isa/Makefile. It this the right way?

[aswaterman]

@ybc-alkaid My mistake, it looks like you did it correctly.

How did you test these tests? Do you have a prototype of SPMP in Spike so that you can successfully execute make run in the isa/ directory?

[ybc-alkaid]

@aswaterman Yes, I test it via my Spike prototype: https://github.com/ybc-alkaid/riscv-isa-sim
This implementation is only for basic tests, and does not support resource sharing (i.e., mpmpdeleg).
The simulator that complies with the SPMP specification is QEMU: https://github.com/luisccc/qemu/tree/feat/spmp

execute make run in the isa/ directory

That requires a minor modification to the Makefile. I've updated it.

[aswaterman]

Yes, I test it via my Spike prototype

Cool. Once the Spike stuff is merged, we can merge this PR, too.