forked from Mirrors/opensbi

Zicfilp / Zicfiss extension (see link) introduces b2 (LPE) in menvcfg CSR to enable landing pads and b3 (SSE) in menvcfg CSR to enable shadow stack and landing pad for privilege less than M. Additionally extension introduces new bits in *status for recording landing pad state and a new exception type `software check exception` with cause=0x12. Link: https://github.com/riscv/riscv-cfi Signed-off-by: Deepak Gupta <debug@rivosinc.com> Reviewed-by: Atish Patra <atishp@rivosinc.com> Reviewed-by: Samuel Holland <samuel.holland@sifive.com>