Re: [PATCH v2] target/riscv: set tval for triggered watchpoints

[Alistair Francis]

On Wed, Feb 1, 2023 at 3:35 AM Sergey Matyukevich <geomatsi@gmail.com> wrote:
>
> From: Sergey Matyukevich <sergey.matyukevich@syntacore.com>
>
> According to priviledged spec, if [sm]tval is written with a nonzero
> value when a breakpoint exception occurs, then [sm]tval will contain
> the faulting virtual address. Set tval to hit address when breakpoint
> exception is triggered by hardware watchpoint.
>
> Signed-off-by: Sergey Matyukevich <sergey.matyukevich@syntacore.com>

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

Alistair

>
> ---
>
> v1 -> v2
> - do not set tval blindly for every breakpoint exception,
>   handle current specific case under consideration
>
>  target/riscv/cpu_helper.c | 6 ++++++
>  target/riscv/debug.c      | 1 -
>  2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c
> index 9a28816521..f1a0c65ad3 100644
> --- a/target/riscv/cpu_helper.c
> +++ b/target/riscv/cpu_helper.c
> @@ -1641,6 +1641,12 @@ void riscv_cpu_do_interrupt(CPUState *cs)
>          case RISCV_EXCP_VIRT_INSTRUCTION_FAULT:
>              tval = env->bins;
>              break;
> +        case RISCV_EXCP_BREAKPOINT:
> +            if (cs->watchpoint_hit) {
> +                tval = cs->watchpoint_hit->hitaddr;
> +                cs->watchpoint_hit = NULL;
> +            }
> +            break;
>          default:
>              break;
>          }
> diff --git a/target/riscv/debug.c b/target/riscv/debug.c
> index bf4840a6a3..b091293069 100644
> --- a/target/riscv/debug.c
> +++ b/target/riscv/debug.c
> @@ -761,7 +761,6 @@ void riscv_cpu_debug_excp_handler(CPUState *cs)
>
>      if (cs->watchpoint_hit) {
>          if (cs->watchpoint_hit->flags & BP_CPU) {
> -            cs->watchpoint_hit = NULL;
>              do_trigger_action(env, DBG_ACTION_BP);
>          }
>      } else {
> --
> 2.39.0
>
>