Re: [PATCH 4/4] target/riscv: Set the value of CSR tcontrol when mret is executed

[Daniel Henrique Barboza]

On 2/16/24 03:13, Alvin Chang wrote:
> The RISC-V debug specification defines the following operation for CSR
> tcontrol when "mret" is executed:
> - tcontrol.MTE is set to the value of tcontrol.MPTE
>
> This commit implements the above operation into helper_mret().
>
> Note that from tech-debug mailing list:
> https://lists.riscv.org/g/tech-debug/topic/102702615#1461
> The debug specification does not mention the operation to tcontrol.MPTE
> when "mret" is executed. Therefore, we just keep its current value.
>
> Signed-off-by: Alvin Chang <alvinga@andestech.com>
> ---

Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

>   target/riscv/op_helper.c | 6 ++++++
>   1 file changed, 6 insertions(+)
>
> diff --git a/target/riscv/op_helper.c b/target/riscv/op_helper.c
> index f414aaebdb..12822b3afa 100644
> --- a/target/riscv/op_helper.c
> +++ b/target/riscv/op_helper.c
> @@ -347,6 +347,12 @@ target_ulong helper_mret(CPURISCVState *env)
>           mstatus = set_field(mstatus, MSTATUS_MPRV, 0);
>       }
>       env->mstatus = mstatus;
> +
> +    uint64_t tcontrol = env->tcontrol;
> +    tcontrol = set_field(tcontrol, TCONTROL_MTE,
> +                         get_field(tcontrol, TCONTROL_MPTE));
> +    env->tcontrol = tcontrol;
> +
>       riscv_cpu_set_mode(env, prev_priv);
>   
>       if (riscv_has_ext(env, RVH)) {