Re: [PATCH v2 10/14] target/ppc: 405: Debug exception cleanup

[David Gibson]

On Tue, Jan 18, 2022 at 03:44:44PM -0300, Fabiano Rosas wrote:
> The current Debug exception dispatch is the BookE one, so it is
> different from the 405. We effectively don't support the 405 Debug
> exception.
> 
> This patch removes the BookE code and moves the DEBUG into the "not
> implemented" block.
> 
> Note that there is in theory a functional change here since we now
> abort when a Debug exception happens. However, given how it was never
> implemented, I don't believe this to have ever been dispatched for the
> 405.
> 
> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  target/ppc/excp_helper.c | 18 ++++--------------
>  1 file changed, 4 insertions(+), 14 deletions(-)
> 
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index d263f20002..84ec7e094a 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -539,23 +539,13 @@ static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
>      case POWERPC_EXCP_DTLB:      /* Data TLB error                           
> */
>      case POWERPC_EXCP_ITLB:      /* Instruction TLB error                    
> */
>          break;
> -    case POWERPC_EXCP_DEBUG:     /* Debug interrupt                          
> */
> -        if (env->flags & POWERPC_FLAG_DE) {
> -            /* FIXME: choose one or the other based on CPU type */
> -            srr0 = SPR_BOOKE_DSRR0;
> -            srr1 = SPR_BOOKE_DSRR1;
> -
> -            env->spr[SPR_BOOKE_CSRR0] = env->nip;
> -            env->spr[SPR_BOOKE_CSRR1] = msr;
> -
> -            /* DBSR already modified by caller */
> -        } else {
> -            cpu_abort(cs, "Debug exception triggered on unsupported 
> model\n");
> -        }
> -        break;
>      case POWERPC_EXCP_PIT:       /* Programmable interval timer interrupt    
> */
>          trace_ppc_excp_print("PIT");
>          break;
> +    case POWERPC_EXCP_DEBUG:     /* Debug interrupt                          
> */
> +        cpu_abort(cs, "%s exception not implemented\n",
> +                  powerpc_excp_name(excp));
> +        break;
>      default:
>          cpu_abort(cs, "Invalid PowerPC exception %d. Aborting\n", excp);
>          break;

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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