[libre-riscv-dev] CSR control of architectural hints

[Luke Kenneth Casson Leighton]

Off-list discussion, documenting.

Speculation barrier hints are needed, for in-process protection. However
RISCV Foundation is not responding on need to allocate an official hint.

If hardware goes ahead and selects the wrong hint, it will be money wasted.

So the idea raised by Jacob is to allow hints to be *reallocated* to
different purposes, through CSRs.

I raised the potential hazard of the hint requiring arguments (from src
registers).

L.


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