BERI stands for Bluespec Extensible RISC Implementation, based on MIPS.
BERI has not implemented standard MIPS perfomance monitoring counters,
instead it provides statistical counters.
BERI statcounters have a several limitations:
- They can't be written
- They don't support start/stop operation
- None of hardware interrupt is provided on a counter overflow.
So make it separate to hwpmc_mips module and support process/system
counting mode only.
Sponsored by: DARPA, AFRL
