Supervisor software can enable control flow integrity features for itself
using fwft feature `SBI_FWFT_LANDING_PAD` and `SBI_FWFT_SHADOW_STACK`.
This patch implements the mechanism to enable both these fwft.
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Clément Léger <cleger@rivosinc.com>
zicfiss and zicfilp introduces new exception (cause=18). Delegate this
exception to S mode because cfi violations in U / S will be reported
via this exception.
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
This patch adds support to check for zicfilp / zicfiss extension.
zicfilp record status of hart's ELP state in *status csr. Missing landing
pad sets MPELP in mstatus. When SBI is redirecting back to S/VS/HS, SPELP
is set in sstatus/vsstatus.
Signed-off-by: Deepak Gupta <debug@rivosinc.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Reviewed-by: Samuel Holland <samuel.holland@sifive.com>
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>
