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

[Jakub Horak <thement@ibawizard.net>]

Hello,

David Gibson (david@gibson.dropbear.id.au) 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 <thement@ibawizard.net>

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.

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