Re: [PATCH] target/riscv: Support configuarable marchid, mvendorid, mipid CSR values

[Alistair Francis]

On Fri, Apr 15, 2022 at 7:37 PM <frank.chang@sifive.com> wrote:
>
> From: Frank Chang <frank.chang@sifive.com>
>
> Allow user to set core's marchid, mvendorid, mipid CSRs through
> -cpu command line option.
>
> Signed-off-by: Frank Chang <frank.chang@sifive.com>
> Reviewed-by: Jim Shu <jim.shu@sifive.com>
> ---
>  target/riscv/cpu.c |  4 ++++
>  target/riscv/cpu.h |  4 ++++
>  target/riscv/csr.c | 38 ++++++++++++++++++++++++++++++++++----
>  3 files changed, 42 insertions(+), 4 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index ddda4906ff..2eea0f9be7 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -786,6 +786,10 @@ static Property riscv_cpu_properties[] = {
>      DEFINE_PROP_UINT16("vlen", RISCVCPU, cfg.vlen, 128),
>      DEFINE_PROP_UINT16("elen", RISCVCPU, cfg.elen, 64),
>
> +    DEFINE_PROP_UINT32("mvendorid", RISCVCPU, cfg.mvendorid, 0),
> +    DEFINE_PROP_UINT64("marchid", RISCVCPU, cfg.marchid, 0),
> +    DEFINE_PROP_UINT64("mipid", RISCVCPU, cfg.mipid, 0),

Should we have non-zero defaults here?

Alistair

> +
>      DEFINE_PROP_BOOL("svinval", RISCVCPU, cfg.ext_svinval, false),
>      DEFINE_PROP_BOOL("svnapot", RISCVCPU, cfg.ext_svnapot, false),
>      DEFINE_PROP_BOOL("svpbmt", RISCVCPU, cfg.ext_svpbmt, false),
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index c069fe85fa..3ab92deb4b 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -370,6 +370,10 @@ struct RISCVCPUConfig {
>      bool ext_zve32f;
>      bool ext_zve64f;
>
> +    uint32_t mvendorid;
> +    uint64_t marchid;
> +    uint64_t mipid;
> +
>      /* Vendor-specific custom extensions */
>      bool ext_XVentanaCondOps;
>
> diff --git a/target/riscv/csr.c b/target/riscv/csr.c
> index 341c2e6f23..9a02038adb 100644
> --- a/target/riscv/csr.c
> +++ b/target/riscv/csr.c
> @@ -603,6 +603,36 @@ static RISCVException write_ignore(CPURISCVState *env, 
> int csrno,
>      return RISCV_EXCP_NONE;
>  }
>
> +static RISCVException read_mvendorid(CPURISCVState *env, int csrno,
> +                                     target_ulong *val)
> +{
> +    CPUState *cs = env_cpu(env);
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +
> +    *val = cpu->cfg.mvendorid;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_marchid(CPURISCVState *env, int csrno,
> +                                   target_ulong *val)
> +{
> +    CPUState *cs = env_cpu(env);
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +
> +    *val = cpu->cfg.marchid;
> +    return RISCV_EXCP_NONE;
> +}
> +
> +static RISCVException read_mipid(CPURISCVState *env, int csrno,
> +                                 target_ulong *val)
> +{
> +    CPUState *cs = env_cpu(env);
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +
> +    *val = cpu->cfg.mipid;
> +    return RISCV_EXCP_NONE;
> +}
> +
>  static RISCVException read_mhartid(CPURISCVState *env, int csrno,
>                                     target_ulong *val)
>  {
> @@ -3098,10 +3128,10 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
>      [CSR_MINSTRETH] = { "minstreth", any32, read_instreth },
>
>      /* Machine Information Registers */
> -    [CSR_MVENDORID] = { "mvendorid", any,   read_zero    },
> -    [CSR_MARCHID]   = { "marchid",   any,   read_zero    },
> -    [CSR_MIMPID]    = { "mimpid",    any,   read_zero    },
> -    [CSR_MHARTID]   = { "mhartid",   any,   read_mhartid },
> +    [CSR_MVENDORID] = { "mvendorid", any,   read_mvendorid },
> +    [CSR_MARCHID]   = { "marchid",   any,   read_marchid   },
> +    [CSR_MIMPID]    = { "mimpid",    any,   read_mipid     },
> +    [CSR_MHARTID]   = { "mhartid",   any,   read_mhartid   },
>
>      /* Machine Trap Setup */
>      [CSR_MSTATUS]     = { "mstatus",    any,   read_mstatus,     
> write_mstatus, NULL,
> --
> 2.35.1
>
>