Re: [PATCH v2 3/7] target/riscv: debug: Implement debug related TCGCPUOps

[Alistair Francis]

On Sat, Oct 30, 2021 at 11:59 PM Bin Meng <bmeng.cn@gmail.com> wrote:
>
> Implement .debug_excp_handler, .debug_check_{breakpoint, watchpoint}
> TCGCPUOps and hook them into riscv_tcg_ops.
>
> Signed-off-by: Bin Meng <bin.meng@windriver.com>

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

Alistair

>
> ---
>
> Changes in v2:
> - use 0 instead of GETPC()
>
>  target/riscv/debug.h |  4 +++
>  target/riscv/cpu.c   |  3 ++
>  target/riscv/debug.c | 75 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 82 insertions(+)
>
> diff --git a/target/riscv/debug.h b/target/riscv/debug.h
> index cb8a6e0024..fddc103650 100644
> --- a/target/riscv/debug.h
> +++ b/target/riscv/debug.h
> @@ -107,4 +107,8 @@ void tdata_csr_write(CPURISCVState *env, int tdata_index, 
> target_ulong val);
>
>  void riscv_trigger_init(CPURISCVState *env);
>
> +void riscv_cpu_debug_excp_handler(CPUState *cs);
> +bool riscv_cpu_debug_check_breakpoint(CPUState *cs);
> +bool riscv_cpu_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp);
> +
>  #endif /* RISCV_DEBUG_H */
> diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
> index 7d53125dbc..7061ae05fb 100644
> --- a/target/riscv/cpu.c
> +++ b/target/riscv/cpu.c
> @@ -701,6 +701,9 @@ static const struct TCGCPUOps riscv_tcg_ops = {
>      .do_interrupt = riscv_cpu_do_interrupt,
>      .do_transaction_failed = riscv_cpu_do_transaction_failed,
>      .do_unaligned_access = riscv_cpu_do_unaligned_access,
> +    .debug_excp_handler = riscv_cpu_debug_excp_handler,
> +    .debug_check_breakpoint = riscv_cpu_debug_check_breakpoint,
> +    .debug_check_watchpoint = riscv_cpu_debug_check_watchpoint,
>  #endif /* !CONFIG_USER_ONLY */
>  };
>
> diff --git a/target/riscv/debug.c b/target/riscv/debug.c
> index 9bcca27b72..9cb2a6d7ba 100644
> --- a/target/riscv/debug.c
> +++ b/target/riscv/debug.c
> @@ -364,3 +364,78 @@ void riscv_trigger_init(CPURISCVState *env)
>          env->trigger_type2[i].wp = NULL;
>      }
>  }
> +
> +void riscv_cpu_debug_excp_handler(CPUState *cs)
> +{
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +    CPURISCVState *env = &cpu->env;
> +
> +    if (cs->watchpoint_hit) {
> +        if (cs->watchpoint_hit->flags & BP_CPU) {
> +            cs->watchpoint_hit = NULL;
> +            riscv_raise_exception(env, RISCV_EXCP_BREAKPOINT, 0);
> +        }
> +    } else {
> +        if (cpu_breakpoint_test(cs, env->pc, BP_CPU)) {
> +            riscv_raise_exception(env, RISCV_EXCP_BREAKPOINT, 0);
> +        }
> +    }
> +}
> +
> +bool riscv_cpu_debug_check_breakpoint(CPUState *cs)
> +{
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +    CPURISCVState *env = &cpu->env;
> +    CPUBreakpoint *bp;
> +    target_ulong ctrl;
> +    target_ulong pc;
> +    int i;
> +
> +    QTAILQ_FOREACH(bp, &cs->breakpoints, entry) {
> +        for (i = 0; i < TRIGGER_TYPE2_NUM; i++) {
> +            ctrl = env->trigger_type2[i].mcontrol;
> +            pc = env->trigger_type2[i].maddress;
> +
> +            if ((ctrl & TYPE2_EXEC) && (bp->pc == pc)) {
> +                /* check U/S/M bit against current privilege level */
> +                if ((ctrl >> 3) & BIT(env->priv)) {
> +                    return true;
> +                }
> +            }
> +        }
> +    }
> +
> +    return false;
> +}
> +
> +bool riscv_cpu_debug_check_watchpoint(CPUState *cs, CPUWatchpoint *wp)
> +{
> +    RISCVCPU *cpu = RISCV_CPU(cs);
> +    CPURISCVState *env = &cpu->env;
> +    target_ulong ctrl;
> +    target_ulong addr;
> +    int flags;
> +    int i;
> +
> +    for (i = 0; i < TRIGGER_TYPE2_NUM; i++) {
> +        ctrl = env->trigger_type2[i].mcontrol;
> +        addr = env->trigger_type2[i].maddress;
> +        flags = 0;
> +
> +        if (ctrl & TYPE2_LOAD) {
> +            flags |= BP_MEM_READ;
> +        }
> +        if (ctrl & TYPE2_STORE) {
> +            flags |= BP_MEM_WRITE;
> +        }
> +
> +        if ((wp->flags & flags) && (wp->vaddr == addr)) {
> +            /* check U/S/M bit against current privilege level */
> +            if ((ctrl >> 3) & BIT(env->priv)) {
> +                return true;
> +            }
> +        }
> +    }
> +
> +    return false;
> +}
> --
> 2.25.1
>
>