Re: [PATCH v2 05/28] target/arm: Use gen_jmp for ISB and SB

[Richard Henderson]

On 7/8/21 5:05 AM, Peter Maydell wrote:
> On Wed, 30 Jun 2021 at 19:47, Richard Henderson
> <richard.henderson@linaro.org> wrote:
> > Using gen_goto_tb directly misses the single-step check.
> >
> > Cc: qemu-arm@nongnu.org
> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> > ---
> >   target/arm/translate.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/target/arm/translate.c b/target/arm/translate.c
> > index a0c6cfa902..8cd31feeaa 100644
> > --- a/target/arm/translate.c
> > +++ b/target/arm/translate.c
> > @@ -8582,7 +8582,7 @@ static bool trans_ISB(DisasContext *s, arg_ISB *a)
> >        * self-modifying code correctly and also to take
> >        * any pending interrupts immediately.
> >        */
> > -    gen_goto_tb(s, 0, s->base.pc_next);
> > +    gen_jmp(s, s->base.pc_next);
> >       return true;
> >   }
> >
> > @@ -8596,7 +8596,7 @@ static bool trans_SB(DisasContext *s, arg_SB *a)
> >        * for TCG; MB and end the TB instead.
> >        */
> >       tcg_gen_mb(TCG_MO_ALL | TCG_BAR_SC);
> > -    gen_goto_tb(s, 0, s->base.pc_next);
> > +    gen_jmp(s, s->base.pc_next);
> >       return true;
>
> Why isn't it enough here just to set is_jmp to DISAS_NEXT ?

You mean DISAS_TOO_MANY?  That would work, yes.
At the time I was just thinking of replacing one jump with another.


r~