Re: [PATCH 8/8] target/ppc: 405: System call exception cleanup

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jan 10, 2022 at 03:15:46PM -0300, Fabiano Rosas wrote:
> There's no sc 1.
> 
> We also only used env->nip because of the vhyp code, so change to
> 'vector' now.

I don't think this is right.  The point with the env->nip change is
changing the PC as it appeared *before* saving it to SRR0, so that
we'll eventually return to the right place.  'vector' is the address
for the interrupt vector itself.


> 
> Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
> ---
>  target/ppc/excp_helper.c | 23 +++--------------------
>  1 file changed, 3 insertions(+), 20 deletions(-)
> 
> diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
> index f7b9af5065..ab298d0d8f 100644
> --- a/target/ppc/excp_helper.c
> +++ b/target/ppc/excp_helper.c
> @@ -398,7 +398,7 @@ static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
>      CPUPPCState *env = &cpu->env;
>      int excp_model = env->excp_model;
>      target_ulong msr, new_msr, vector;
> -    int srr0, srr1, lev = -1;
> +    int srr0, srr1;
>  
>      if (excp <= POWERPC_EXCP_NONE || excp >= POWERPC_EXCP_NB) {
>          cpu_abort(cs, "Invalid PowerPC exception %d. Aborting\n", excp);
> @@ -518,30 +518,13 @@ static void powerpc_excp_40x(PowerPCCPU *cpu, int excp)
>          }
>          break;
>      case POWERPC_EXCP_SYSCALL:   /* System call exception                    */
> -        lev = env->error_code;
> -
> -        if ((lev == 1) && cpu->vhyp) {
> -            dump_hcall(env);
> -        } else {
> -            dump_syscall(env);
> -        }
> +        dump_syscall(env);
>  
>          /*
>           * We need to correct the NIP which in this case is supposed
>           * to point to the next instruction
>           */
> -        env->nip += 4;
> -
> -        /* "PAPR mode" built-in hypercall emulation */
> -        if ((lev == 1) && cpu->vhyp) {
> -            PPCVirtualHypervisorClass *vhc =
> -                PPC_VIRTUAL_HYPERVISOR_GET_CLASS(cpu->vhyp);
> -            vhc->hypercall(cpu->vhyp, cpu);
> -            return;
> -        }
> -        if (lev == 1) {
> -            new_msr |= (target_ulong)MSR_HVB;
> -        }
> +        vector += 4;
>          break;
>      case POWERPC_EXCP_FPU:       /* Floating-point unavailable exception     */
>      case POWERPC_EXCP_APU:       /* Auxiliary processor unavailable          */

-- 
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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