Re: [Qemu-devel] [Qemu-ppc] Bug in ppc/BookE wait instruction

[David Gibson]

On Mon, Jun 06, 2016 at 10:47:28AM +0200, Jakub Horak wrote:
> 
> Hello,
> 
> David Gibson (address@hidden) wrote:
> > On Fri, Jun 03, 2016 at 05:45:49PM +0200, Jakub Horak wrote:
> > > Hello,
> > > I think there's a bug in "wait" instruction code generator for PowerPC
> > > architecture. It doesn't make sense to store a non-initialized register.
> > > 
> > > Best regards,
> > > Jakub Horak
> > 
> > The fix looks correct, but I need a Signed-off-by line in order to
> > apply it.
> 
> Here you go:
> 
>     Fixed bug in code generator.
>     
>     Signed-off-by: Jakub Horak <address@hidden>
> 
> diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> index f5ceae5..6af567b 100644
> --- a/target-ppc/translate.c
> +++ b/target-ppc/translate.c
> @@ -3439,7 +3439,7 @@ static void gen_sync(DisasContext *ctx)
>  /* wait */
>  static void gen_wait(DisasContext *ctx)
>  {
> -    TCGv_i32 t0 = tcg_temp_new_i32();
> +    TCGv_i32 t0 = tcg_const_i32(1);
>      tcg_gen_st_i32(t0, cpu_env,
>                     -offsetof(PowerPCCPU, env) + offsetof(CPUState, halted));
>      tcg_temp_free_i32(t0);
> 
> 
> > 
> > In future, please send such patches to myself and Alex Graf
> > (target-ppc maintainers) the qemu-ppc list as well as qemu-devel.  I
> > wouldn't have spotted this if Marc Cave-Ayland hadn't copied it to me.
> 
> Sorry, I'll be more thoughtful next time.

Sorry, I forgot about this one after you resent, I've now applied to 
ppc-for-2.7.

> 
> Best regards,
> Jakub 
> 
> > 
> > > 
> > > 
> > > diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> > > index f5ceae5..6af567b 100644
> > > --- a/target-ppc/translate.c
> > > +++ b/target-ppc/translate.c
> > > @@ -3439,7 +3439,7 @@ static void gen_sync(DisasContext *ctx)
> > >  /* wait */
> > >  static void gen_wait(DisasContext *ctx)
> > >  {
> > > -    TCGv_i32 t0 = tcg_temp_new_i32();
> > > +    TCGv_i32 t0 = tcg_const_i32(1);
> > >      tcg_gen_st_i32(t0, cpu_env,
> > >                     -offsetof(PowerPCCPU, env) + offsetof(CPUState, 
> > > halted));
> > >      tcg_temp_free_i32(t0);
> > > 
> > 
> 
> 
> 

-- 
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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