Can mhpmcounter19h be accessed from any privilege level?
No. The official CSR table lists mhpmcounter19h as an RV32-only Machine read/write CSR.
mhpmcounter19h at 0xB93 is the RV32 machine high-half CSR for bits 63:32 of mhpmcounter19.
mhpmcounter19h is the RV32 high-half access CSR for bits 63:32 of mhpmcounter19; its event meaning is still determined by mhpmevent19.
On RV32, access mhpmcounter19h and mhpmcounter19 separately.
The high and low halves correspond to bits 63:32 and 31:0 of one WARL counter.
Use mhpmevent19 to determine the platform-selected event for the counter.
No. The official CSR table lists mhpmcounter19h as an RV32-only Machine read/write CSR.
No. It is only the RV32 access CSR for the upper 32 bits of mhpmcounter19.