Hi everybody, I recently started using RISCV architectures, I would need a way to access “hpmcounter[3-31]” registers using QEMU emulator.
The kernel used for simulations is a C program, not a heavy operating system, which is why I would need to access the registers mentioned before via assembly.
Trivially accessing any of those registers always returns zero.
The question is:
Are these registers enabled in QEMU? If not, is it possible to enable them or are they hardwired to zero? How?
Trying to access the registers “cycle”, “instret” and “time” the values come out to be non-zero, which is why I think it is also possible to enable “hpmcounter[3-31]”, but the mode of operation
is unknown to me, can anyone help me?
Regards,
Elio