Re: [PATCH v2 07/14] target/ppc: 405: External exception cleanup

[Fabiano Rosas <farosas@linux.ibm.com>]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 1/19/22 5:44 AM, Fabiano Rosas wrote:
>> 405 has no MSR_HV and EPR is BookE only so we can remove it all.
>> 
>> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
>> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
>> ---
>>   target/ppc/excp_helper.c | 37 -------------------------------------
>>   1 file changed, 37 deletions(-)
>> 
>> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
>> index e98d783ecd..8fae8aa0be 100644
>> --- a/target/ppc/excp_helper.c
>> +++ b/target/ppc/excp_helper.c
>> @@ -472,44 +472,7 @@ static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
>>           msr |= env->error_code;
>>           break;
>>       case POWERPC_EXCP_EXTERNAL:  /* External input                           */
>> -    {
>> -        bool lpes0;
>> -
>> -        cs = CPU(cpu);
>> -
>> -        /*
>> -         * Exception targeting modifiers
>> -         *
>> -         * LPES0 is supported on POWER7/8/9
>> -         * LPES1 is not supported (old iSeries mode)
>> -         *
>> -         * On anything else, we behave as if LPES0 is 1
>> -         * (externals don't alter MSR:HV)
>> -         */
>> -#if defined(TARGET_PPC64)
>> -        if (excp_model == POWERPC_EXCP_POWER7 ||
>> -            excp_model == POWERPC_EXCP_POWER8 ||
>> -            excp_model == POWERPC_EXCP_POWER9 ||
>> -            excp_model == POWERPC_EXCP_POWER10) {
>> -            lpes0 = !!(env->spr[SPR_LPCR] & LPCR_LPES0);
>> -        } else
>> -#endif /* defined(TARGET_PPC64) */
>> -        {
>> -            lpes0 = true;
>> -        }
>> -
>> -        if (!lpes0) {
>> -            new_msr |= (target_ulong)MSR_HVB;
>> -            new_msr |= env->msr & ((target_ulong)1 << MSR_RI);
>> -            srr0 = SPR_HSRR0;
>> -            srr1 = SPR_HSRR1;
>> -        }
>> -        if (env->mpic_proxy) {
>> -            /* IACK the IRQ on delivery */
>> -            env->spr[SPR_BOOKE_EPR] = ldl_phys(cs->as, env->mpic_iack);
>> -        }
>>           break;
>> -    }
>
> Bare break?  Should this be reachable at all?
> Should it in fact be g_assert_not_reached()?

It should be reachable. It is a valid exception for this CPU. We just
don't have anything else to do to dispatch it aside from what is done in
the generic code outside the switch statement.