Re: [PATCH v7 2/4] target/riscv: Enable mcontrol6 triggers only when sdtrig is selected

[Andrew Jones]

On Fri, Mar 15, 2024 at 12:29:55AM +0530, Himanshu Chauhan wrote:
> The mcontrol6 triggers are not defined in debug specification v0.13
> These triggers are defined in sdtrig ISA extension.
> 
> This patch:
>    * Adds ext_sdtrig capability which is used to select mcontrol6 triggers
>    * Keeps the debug property. All triggers that are defined in v0.13 are
>      exposed.
> 
> Signed-off-by: Himanshu Chauhan <hchauhan@ventanamicro.com>
> ---
>  target/riscv/cpu.c     |  5 +++++
>  target/riscv/cpu_cfg.h |  1 +
>  target/riscv/debug.c   | 30 +++++++++++++++++++++++++-----
>  3 files changed, 31 insertions(+), 5 deletions(-)
> 
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index c160b9216b..ab631500ac 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -1008,6 +1008,11 @@ static void riscv_cpu_reset_hold(Object *obj)
>      set_default_nan_mode(1, &env->fp_status);
>  
>  #ifndef CONFIG_USER_ONLY
> +    if (!cpu->cfg.debug && cpu->cfg.ext_sdtrig) {
> +        warn_report("Enabling 'debug' since 'sdtrig' is enabled.");
> +        cpu->cfg.debug = true;
> +    }
> +
>      if (cpu->cfg.debug) {
>          riscv_trigger_reset_hold(env);
>      }
> diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
> index 2040b90da0..0c57e1acd4 100644
> --- a/target/riscv/cpu_cfg.h
> +++ b/target/riscv/cpu_cfg.h
> @@ -114,6 +114,7 @@ struct RISCVCPUConfig {
>      bool ext_zvfbfwma;
>      bool ext_zvfh;
>      bool ext_zvfhmin;
> +    bool ext_sdtrig;
>      bool ext_smaia;
>      bool ext_ssaia;
>      bool ext_sscofpmf;
> diff --git a/target/riscv/debug.c b/target/riscv/debug.c
> index 5f14b39b06..c40e727e12 100644
> --- a/target/riscv/debug.c
> +++ b/target/riscv/debug.c
> @@ -100,13 +100,16 @@ static trigger_action_t 
> get_trigger_action(CPURISCVState *env,
>      target_ulong tdata1 = env->tdata1[trigger_index];
>      int trigger_type = get_trigger_type(env, trigger_index);
>      trigger_action_t action = DBG_ACTION_NONE;
> +    const RISCVCPUConfig *cfg = riscv_cpu_cfg(env);
>  
>      switch (trigger_type) {
>      case TRIGGER_TYPE_AD_MATCH:
>          action = (tdata1 & TYPE2_ACTION) >> 12;
>          break;
>      case TRIGGER_TYPE_AD_MATCH6:
> -        action = (tdata1 & TYPE6_ACTION) >> 12;
> +        if (cfg->ext_sdtrig) {
> +            action = (tdata1 & TYPE6_ACTION) >> 12;
> +        }
>          break;
>      case TRIGGER_TYPE_INST_CNT:
>      case TRIGGER_TYPE_INT:
> @@ -727,7 +730,12 @@ void tdata_csr_write(CPURISCVState *env, int 
> tdata_index, target_ulong val)
>          type2_reg_write(env, env->trigger_cur, tdata_index, val);
>          break;
>      case TRIGGER_TYPE_AD_MATCH6:
> -        type6_reg_write(env, env->trigger_cur, tdata_index, val);
> +        if (riscv_cpu_cfg(env)->ext_sdtrig) {
> +            type6_reg_write(env, env->trigger_cur, tdata_index, val);
> +        } else {
> +            qemu_log_mask(LOG_UNIMP, "trigger type: %d is not supported\n",
> +                          trigger_type);
> +        }
>          break;
>      case TRIGGER_TYPE_INST_CNT:
>          itrigger_reg_write(env, env->trigger_cur, tdata_index, val);
> @@ -750,9 +758,13 @@ void tdata_csr_write(CPURISCVState *env, int 
> tdata_index, target_ulong val)
>  
>  target_ulong tinfo_csr_read(CPURISCVState *env)
>  {
> -    /* assume all triggers support the same types of triggers */
> -    return BIT(TRIGGER_TYPE_AD_MATCH) |
> -           BIT(TRIGGER_TYPE_AD_MATCH6);
> +    target_ulong ts = BIT(TRIGGER_TYPE_AD_MATCH);
> +
> +    if (riscv_cpu_cfg(env)->ext_sdtrig) {
> +        ts |= BIT(TRIGGER_TYPE_AD_MATCH6);
> +    }
> +
> +    return ts;
>  }
>  
>  void riscv_cpu_debug_excp_handler(CPUState *cs)
> @@ -803,6 +815,10 @@ bool riscv_cpu_debug_check_breakpoint(CPUState *cs)
>                  }
>                  break;
>              case TRIGGER_TYPE_AD_MATCH6:
> +                if (!cpu->cfg.ext_sdtrig) {
> +                    break;
> +                }
> +
>                  ctrl = env->tdata1[i];
>                  pc = env->tdata2[i];
>  
> @@ -869,6 +885,10 @@ bool riscv_cpu_debug_check_watchpoint(CPUState *cs, 
> CPUWatchpoint *wp)
>              }
>              break;
>          case TRIGGER_TYPE_AD_MATCH6:
> +            if (!cpu->cfg.ext_sdtrig) {
> +                break;
> +            }
> +
>              ctrl = env->tdata1[i];
>              addr = env->tdata2[i];
>              flags = 0;
> -- 
> 2.34.1
>

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>