Re: [Qemu-devel] [PATCH] PPC: Fix for the gdb single step problem on an rfi instruction

[Elie Richa <richa@adacore.com>]

Hello,

I've had this problem recently and your patch does fix the issue, thanks!

Regards,
Elie

On 08/10/2011 01:41 PM, Sebastian Bauer wrote:
> When using gdb to single step a ppc interrupt routine, the execution flow passes
> the rfi instruction without actually returning from the interrupt. The patch
> fixes this by avoiding to update the nip when the debug exception is raised
> and a previous POWERPC_EXCP_SYNC was set. The latter is the case only, if code for
> rfi or a related instruction was generated.
>
> Signed-off-by: Sebastian Bauer <mail@sebastianbauer.info>
> ---
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index fd7c208..42b91fd 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -287,7 +287,7 @@ static inline void gen_debug_exception(DisasContext *ctx)
> {
> TCGv_i32 t0;
>
> - if (ctx->exception != POWERPC_EXCP_BRANCH)
> + if (ctx->exception != POWERPC_EXCP_BRANCH && ctx->exception != POWERPC_EXCP_SYNC)
> gen_update_nip(ctx, ctx->nip);
> t0 = tcg_const_i32(EXCP_DEBUG);
> gen_helper_raise_exception(t0);
>
>