Re: [PATCH v2 3/4] Add ePMP CSR accesses

[Alistair Francis]

On Mon, Aug 10, 2020 at 5:24 PM Hou Weiying <weiying_hou@outlook.com> wrote:
>
> Signed-off-by: Hongzheng-Li <Ethan.Lee.QNL@gmail.com>
> Signed-off-by: Hou Weiying <weiying_hou@outlook.com>
> Signed-off-by: Myriad-Dreamin <camiyoru@gmail.com>
> ---
>  target/riscv/csr.c | 18 ++++++++++++++++++
>  target/riscv/pmp.c | 40 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 58 insertions(+)
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 6a96a01b1c..0bb33baec3 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -104,6 +104,11 @@ static int hmode(CPURISCVState *env, int csrno)
>      return -1;
>  }
>
> +static int epmp(CPURISCVState *env, int csrno)
> +{
> +    return -!(env->priv == PRV_M && riscv_feature(env, RISCV_FEATURE_EPMP));

RISCV_FEATURE_EPMP isn't defined yet, so this fails to compile.

Alistair

> +}
> +
>  static int pmp(CPURISCVState *env, int csrno)
>  {
>      return -!riscv_feature(env, RISCV_FEATURE_PMP);
> @@ -1142,6 +1147,18 @@ static int write_pmpaddr(CPURISCVState *env, int 
> csrno, target_ulong val)
>      return 0;
>  }
>
> +static int read_mseccfg(CPURISCVState *env, int csrno, target_ulong *val)
> +{
> +    *val = mseccfg_csr_read(env);
> +    return 0;
> +}
> +
> +static int write_mseccfg(CPURISCVState *env, int csrno, target_ulong val)
> +{
> +    mseccfg_csr_write(env, val);
> +    return 0;
> +}
> +
>  #endif
>
>  /*
> @@ -1353,6 +1370,7 @@ static riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
>      [CSR_MTINST] =              { hmode,   read_mtinst,      write_mtinst    
>  },
>
>      /* Physical Memory Protection */
> +    [CSR_MSECCFG] =             { epmp,    read_mseccfg,     write_mseccfg   
>  },
>      [CSR_PMPCFG0  ... CSR_PMPCFG3]   = { pmp,   read_pmpcfg,  write_pmpcfg   
> },
>      [CSR_PMPADDR0 ... CSR_PMPADDR15] = { pmp,   read_pmpaddr, write_pmpaddr  
> },
>
> diff --git a/target/riscv/pmp.c b/target/riscv/pmp.c
> index b1fa703aff..97aab0b99e 100644
> --- a/target/riscv/pmp.c
> +++ b/target/riscv/pmp.c
> @@ -494,3 +494,43 @@ target_ulong pmpaddr_csr_read(CPURISCVState *env, 
> uint32_t addr_index)
>
>      return val;
>  }
> +
> +
> +/*
> + * Handle a write to a mseccfg CSR
> + */
> +void mseccfg_csr_write(CPURISCVState *env, target_ulong val)
> +{
> +    int i;
> +
> +    if (!MSECCFG_RLB_ISSET(env)) {
> +        for (i = 0; i < MAX_RISCV_PMPS; i++) {
> +            if (pmp_is_locked(env, i)) {
> +                /*
> +                 * Now that mseccfg.rlb is zero
> +                 * the value of mseccfg.rlb should be locked.
> +                 */
> +                val &= ~MSECCFG_RLB;
> +                break;
> +            }
> +        }
> +    }
> +
> +    /*
> +     * sticky bit
> +     */
> +    val |= (env->mseccfg & (MSECCFG_MMWP | MSECCFG_MML));
> +
> +    env->mseccfg = val;
> +    trace_mseccfg_csr_write(env->mhartid, val);
> +}
> +
> +
> +/*
> + * Handle a read from a mseccfg CSR
> + */
> +target_ulong mseccfg_csr_read(CPURISCVState *env)
> +{
> +    trace_mseccfg_csr_read(env->mhartid, env->mseccfg);
> +    return env->mseccfg;
> +}
> --
> 2.20.1
>
>