Add tests for the Svukte extension

[youngar]

Description

This PR adds basic tests for the Svukte extension, "Address-Independent Latency of User-Mode Faults to Supervisor Addresses", which is currently fast-tracked for ratification.

The testing requirements, outlined in the ratification plan are:

• “Check that an exception is raised/not raised for qualified/unqualified U/VU accesses to the kernel pages above 2^(SXLEN-1), independent of PTE data.”  – Andrew Dellow
  • varying the CSR bits for qualified/unqualified accesses in that mode
  • including the HLS instructions: HLV, HLVX, HSV
• ACT does not test for data independent timing.

Some CSR declarations were added

In Spike, support for this extension was added in riscv-software-src/riscv-isa-sim#2121
In Sail, there is currently no support for this extension, or the hypervisor extension. I plan on adding support for the parts of this extension which do not depend on H to Sail.

This PR is still a bit of a work in progress, but I would greatly appreciate some early feedback. In particular I am not sure if I am following the test naming conventions properly, and how to add tests which we cannot generate reference signatures for using Sail. This PR also depends on several outstanding PRs to fix the trap handling code with the hypervisor extension enabled.

Related Issues

Test development tracking: https://riscv.atlassian.net/browse/RVS-3278

Ratified/Unratified Extensions

• Ratified
• Unratified

List Extensions

Svukte draft specification: riscv/riscv-isa-manual#1564

Reference Model Used

• SAIL
• Spike
• Other - < SPECIFY HERE >

Mandatory Checklist:

• All tests are compliant with the test-format spec present in this repo ?
• Ran the new tests on RISCOF with SAIL/Spike as reference model successfully ?
• Ran the new tests on RISCOF in coverage mode
• Link to Google-Drive folder containing the new coverage reports (See this for more info): < SPECIFY HERE >

Optional Checklist:

• Were the tests hand-written/modified ?
• Have you run these on any hard DUT model ? Please specify name and provide link if possible in the description
• If you have modified arch_test.h Please provide a detailed description of the changes in the Description section above.