ibex
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lowRISC
[rtl] Move to privileged spec v1.12 support
Ibex should move to supporting v1.12 (see ratified draft here: https://github.com/riscv/riscv-isa-manual/releases/download/Priv-v1.12/riscv-privileged-20211203.pdf, document may have some fixes applied and new chapters integrated before the official v1.12 but only on the level of fixing typos and formatting errors and integrating currently stand-alone, ratified, specs, such as ePMP).
Changes required:
- [ ] Add new CSRs with constant value, ignore writes - Estimate 2
- [ ] mstatush
- [ ] mconfigptr - Make constant value configurable via a package parameter
- [ ] menvcfg
- [ ] mseccfg - Already exists when PMP enabled, now when PMP disabled it should be accessible current it just causes an illegal instruction exception
- [ ] Alter mprv behaviour, clear mprv on
mret- Estimate 2 - [ ] Read through v1.12 in detail to determine if there's anything else that needs attention. Look at diff between documentation source between v1.11 and v1.12 to aid this. Implement anything that comes from this - Estimate 8
Closing a task here includes ensuring any relevant coverage is updated.
estimate 16
Final point here is intentionally vague, going by the changes listed at the beginning of the spec there shouldn't be anything else of note, estimate liable to change as I look at v1.12 in more detail.
PR to move to the new specification is here: https://github.com/lowRISC/ibex/pull/1805