Re: [PATCH 4/5] target/riscv: Add MEDELEGH, HEDELEGH csrs for RV32

[LIU Zhiwei <zhiwei_liu@linux.alibaba.com>]

On 2024/5/10 14:58, Fea.Wang wrote:
> Based on privileged spec 1.13, the RV32 needs to implement MEDELEGH
> and HEDELEGH for exception codes 32-47 for reserving and exception codes
> 48-63 for custom use. Add the CSR number though the implementation is
> just reading zero and writing ignore. Besides, for accessing HEDELEGH, it
> should be controlled by mstateen0 'P1P13' bit.
>
> Signed-off-by: Fea.Wang <fea.wang@sifive.com>
> Reviewed-by: Frank Chang <frank.chang@sifive.com>
> ---
>   target/riscv/cpu_bits.h |  2 ++
>   target/riscv/csr.c      | 31 +++++++++++++++++++++++++++++++
>   2 files changed, 33 insertions(+)
>
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 28bd3fb0b4..f888025c59 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -156,6 +156,8 @@
>   
>   /* 32-bit only */
>   #define CSR_MSTATUSH        0x310
> +#define CSR_MEDELEGH        0x312
> +#define CSR_HEDELEGH        0x612
>   
>   /* Machine Trap Handling */
>   #define CSR_MSCRATCH        0x340
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index d844ce770e..4d7313f456 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -3227,6 +3227,33 @@ static RISCVException write_hedeleg(CPURISCVState *env, int csrno,
>       return RISCV_EXCP_NONE;
>   }
>   
> +static RISCVException read_hedelegh(CPURISCVState *env, int csrno,
> +                                   target_ulong *val)
> +{
> +    RISCVException ret;
> +    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_P1P13);
> +    if (ret != RISCV_EXCP_NONE) {
> +        return ret;
> +    }
> +
> +    /* Reserved, now read zero */
> +    *val = 0;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException write_hedelegh(CPURISCVState *env, int csrno,
> +                                    target_ulong val)
> +{
> +    RISCVException ret;
> +    ret = smstateen_acc_ok(env, 0, SMSTATEEN0_P1P13);
> +    if (ret != RISCV_EXCP_NONE) {
> +        return ret;
> +    }
> +
> +    /* Reserved, now write ignore */
> +    return RISCV_EXCP_NONE;
> +}
> +
>   static RISCVException rmw_hvien64(CPURISCVState *env, int csrno,
>                                       uint64_t *ret_val,
>                                       uint64_t new_val, uint64_t wr_mask)
> @@ -4674,6 +4701,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
>   
>       [CSR_MSTATUSH]    = { "mstatush",   any32, read_mstatush,
>                             write_mstatush                                   },
> +    [CSR_MEDELEGH]    = { "medelegh",   any32, read_zero, write_ignore,
> +                          .min_priv_ver = PRIV_VERSION_1_13_0              },
> +    [CSR_HEDELEGH]    = { "hedelegh",   any32, read_hedelegh, write_hedelegh,

Using hmode32 instead of any32.

Otherwise,

Reviewed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>

> +                          .min_priv_ver = PRIV_VERSION_1_13_0              },
>   
>       /* Machine Trap Handling */
>       [CSR_MSCRATCH] = { "mscratch", any,  read_mscratch, write_mscratch,