Re: [RFC v2 02/12] target/ppc: powerpc_excp: Set vector earlier

[Richard Henderson <richard.henderson@linaro.org>]

On 12/20/21 10:18 AM, Fabiano Rosas wrote:
> None of the interrupt setup code touches 'vector', so we can move it
> earlier in the function. This will allow us to later move the System
> Call Vectored setup that is on the top level into the
> POWERPC_EXCP_SYSCALL_VECTORED code block.
> 
> This patch also moves the verification for when 'excp' does not have
> an address associated with it. We now bail a little earlier when that
> is the case. This should not cause any visible effects.
> 
> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
> ---
>   target/ppc/excp_helper.c | 16 ++++++++--------
>   1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index 8b9c6bc5a8..14fd0213a0 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -352,6 +352,14 @@ static inline void powerpc_excp(PowerPCCPU *cpu, int excp_model, int excp)
>       }
>   #endif
>   
> +    vector = env->excp_vectors[excp];
> +    if (vector == (target_ulong)-1ULL) {
> +        cpu_abort(cs, "Raised an exception without defined vector %d\n",
> +                  excp);
> +    }
> +
> +    vector |= env->excp_prefix;
> +
>       switch (excp) {
>       case POWERPC_EXCP_NONE:
>           /* Should never happen */

You've moved the cpu_abort above the excp check above the early return for NONE (which 
possibly shouldn't exist) and above the excp default

         cpu_abort(cs, "Invalid PowerPC exception %d. Aborting\n", excp);

I would certainly expect invalid excp to not have a defined vector either.

I'll also note that the excp_vectors[] index is no longer bounds checked by the switch.


r~