Re: [PATCH v2 1/2] target/riscv/cpu.c: add riscv_bare_cpu_init()

[Alistair Francis]

On Tue, Jan 9, 2024 at 3:32 AM Daniel Henrique Barboza
<dbarboza@ventanamicro.com> wrote:
>
> Next patch will add more bare CPUs. Their cpu_init() functions would be
> glorified copy/pastes of rv64i_bare_cpu_init(), differing only by a
> riscv_cpu_set_misa() call.
>
> Add a new .instance_init for the TYPE_RISCV_BARE_CPU typ to avoid this
> code repetition. While we're at it, add a better explanation on why
> we're disabling the timing extensions for bare CPUs.
>
> Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>

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

Alistair

> ---
>  target/riscv/cpu.c | 45 +++++++++++++++++++++++++++++----------------
>  1 file changed, 29 insertions(+), 16 deletions(-)
>
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index b32681f7f3..1202ec3e57 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -575,22 +575,6 @@ static void rv64i_bare_cpu_init(Object *obj)
>  {
>      CPURISCVState *env = &RISCV_CPU(obj)->env;
>      riscv_cpu_set_misa(env, MXL_RV64, RVI);
> -
> -    /* Remove the defaults from the parent class */
> -    RISCV_CPU(obj)->cfg.ext_zicntr = false;
> -    RISCV_CPU(obj)->cfg.ext_zihpm = false;
> -
> -    /* Set to QEMU's first supported priv version */
> -    env->priv_ver = PRIV_VERSION_1_10_0;
> -
> -    /*
> -     * Support all available satp_mode settings. The default
> -     * value will be set to MBARE if the user doesn't set
> -     * satp_mode manually (see set_satp_mode_default()).
> -     */
> -#ifndef CONFIG_USER_ONLY
> -    set_satp_mode_max_supported(RISCV_CPU(obj), VM_1_10_SV64);
> -#endif
>  }
>  #else
>  static void rv32_base_cpu_init(Object *obj)
> @@ -1266,6 +1250,34 @@ static void riscv_cpu_init(Object *obj)
>      RISCV_CPU(obj)->cfg.ext_zihpm = true;
>  }
>
> +static void riscv_bare_cpu_init(Object *obj)
> +{
> +    RISCVCPU *cpu = RISCV_CPU(obj);
> +
> +    /*
> +     * Bare CPUs do not inherit the timer and performance
> +     * counters from the parent class (see riscv_cpu_init()
> +     * for info on why the parent enables them).
> +     *
> +     * Users have to explicitly enable these counters for
> +     * bare CPUs.
> +     */
> +    cpu->cfg.ext_zicntr = false;
> +    cpu->cfg.ext_zihpm = false;
> +
> +    /* Set to QEMU's first supported priv version */
> +    cpu->env.priv_ver = PRIV_VERSION_1_10_0;
> +
> +    /*
> +     * Support all available satp_mode settings. The default
> +     * value will be set to MBARE if the user doesn't set
> +     * satp_mode manually (see set_satp_mode_default()).
> +     */
> +#ifndef CONFIG_USER_ONLY
> +    set_satp_mode_max_supported(cpu, VM_1_10_SV64);
> +#endif
> +}
> +
>  typedef struct misa_ext_info {
>      const char *name;
>      const char *description;
> @@ -1925,6 +1937,7 @@ static const TypeInfo riscv_cpu_type_infos[] = {
>      {
>          .name = TYPE_RISCV_BARE_CPU,
>          .parent = TYPE_RISCV_CPU,
> +        .instance_init = riscv_bare_cpu_init,
>          .abstract = true,
>      },
>      DEFINE_DYNAMIC_CPU(TYPE_RISCV_CPU_ANY,      riscv_any_cpu_init),
> --
> 2.43.0
>
>