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>
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