Re: [PATCH v4 20/20] target/riscv: Enable uxl field write

[Alistair Francis]

On Fri, Nov 12, 2021 at 2:14 AM LIU Zhiwei <zhiwei_liu@c-sky.com> wrote:
>
> Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

Alistair

> ---
>  target/riscv/cpu_bits.h | 2 ++
>  target/riscv/csr.c      | 8 +++++---
>  2 files changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
> index 9913fa9f77..5106f0e769 100644
> --- a/target/riscv/cpu_bits.h
> +++ b/target/riscv/cpu_bits.h
> @@ -413,6 +413,8 @@ typedef enum {
>  #define SSTATUS_SUM         0x00040000 /* since: priv-1.10 */
>  #define SSTATUS_MXR         0x00080000
>
> +#define SSTATUS64_UXL       0x0000000300000000ULL
> +
>  #define SSTATUS32_SD        0x80000000
>  #define SSTATUS64_SD        0x8000000000000000ULL
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 8f8f170768..e79532053a 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -553,15 +553,14 @@ static RISCVException write_mstatus(CPURISCVState *env, 
> int csrno,
>           * RV32: MPV and GVA are not in mstatus. The current plan is to
>           * add them to mstatush. For now, we just don't support it.
>           */
> -        mask |= MSTATUS_MPV | MSTATUS_GVA;
> +        mask |= MSTATUS_MPV | MSTATUS_GVA | MSTATUS64_UXL;
>      }
>
>      mstatus = (mstatus & ~mask) | (val & mask);
>
>      if (riscv_cpu_mxl(env) == MXL_RV64) {
> -        /* SXL and UXL fields are for now read only */
> +        /* SXL fields are for now read only */
>          mstatus = set_field(mstatus, MSTATUS64_SXL, MXL_RV64);
> -        mstatus = set_field(mstatus, MSTATUS64_UXL, MXL_RV64);
>      }
>      env->mstatus = mstatus;
>
> @@ -840,6 +839,9 @@ static RISCVException write_sstatus(CPURISCVState *env, 
> int csrno,
>                                      target_ulong val)
>  {
>      target_ulong mask = (sstatus_v1_10_mask);
> +    if (cpu_get_xl(env) != MXL_RV32) {
> +        mask |= SSTATUS64_UXL;
> +    }
>      target_ulong newval = (env->mstatus & ~mask) | (val & mask);
>      return write_mstatus(env, CSR_MSTATUS, newval);
>  }
> --
> 2.25.1
>
>