diff options
Diffstat (limited to 'target/riscv/csr.c')
| -rw-r--r-- | target/riscv/csr.c | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/target/riscv/csr.c b/target/riscv/csr.c index e0b871f..f4d2dcf 100644 --- a/target/riscv/csr.c +++ b/target/riscv/csr.c @@ -1230,6 +1230,32 @@ static bool validate_vm(CPURISCVState *env, target_ulong vm) satp_mode_max_from_map(riscv_cpu_cfg(env)->satp_mode.map); } +static target_ulong legalize_mpp(CPURISCVState *env, target_ulong old_mpp, + target_ulong val) +{ + bool valid = false; + target_ulong new_mpp = get_field(val, MSTATUS_MPP); + + switch (new_mpp) { + case PRV_M: + valid = true; + break; + case PRV_S: + valid = riscv_has_ext(env, RVS); + break; + case PRV_U: + valid = riscv_has_ext(env, RVU); + break; + } + + /* Remain field unchanged if new_mpp value is invalid */ + if (!valid) { + val = set_field(val, MSTATUS_MPP, old_mpp); + } + + return val; +} + static RISCVException write_mstatus(CPURISCVState *env, int csrno, target_ulong val) { @@ -1237,6 +1263,12 @@ static RISCVException write_mstatus(CPURISCVState *env, int csrno, uint64_t mask = 0; RISCVMXL xl = riscv_cpu_mxl(env); + /* + * MPP field have been made WARL since priv version 1.11. However, + * legalization for it will not break any software running on 1.10. + */ + val = legalize_mpp(env, get_field(mstatus, MSTATUS_MPP), val); + /* flush tlb on mstatus fields that affect VM */ if ((val ^ mstatus) & (MSTATUS_MXR | MSTATUS_MPP | MSTATUS_MPV | MSTATUS_MPRV | MSTATUS_SUM)) { |