Invalid capability returned by CUnseal

[Andreas-Bur]

There seems to be an issue where the CUnseal instruction produces a capability without tag set, even though it should be valid.

PoC:

  cspecialrw c1,31,cnull
  cseal c2,c1,c1
  cunseal c3,c2,c1
  cgettag x4, c3

Expected value: x4=1
Actual value: x4=0

This was tested with both verilator and bluesim on the RV64ACDFIMSUxCHERI configuration.

[PeterRugg]

Thanks for the report, and sorry for the delay: I have now turned on more notifications for this repo. I'll look into it now.

[PeterRugg]

I hope this is fixed by ed011ac. As you can see, it's very basic: otypes are currently relatively untested in Toooba, both by TestRIG and the software stacks that we run. Please do let me know if this doesn't fix the problem or you run into any further issues!