Re: [PATCH v2] target/sh4: Fix TB_FLAG_UNALIGN

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Dec 12, 2022 at 08:30:42AM -0600, Richard Henderson wrote:
> On 12/11/22 19:13, Guenter Roeck wrote:
> > On Sat, Dec 10, 2022 at 07:27:46AM -0800, Guenter Roeck wrote:
> > > Hi,
> > > 
> > > On Thu, Sep 01, 2022 at 11:15:09AM +0100, Richard Henderson wrote:
> > > > The value previously chosen overlaps GUSA_MASK.
> > > > 
> > > > Rename all DELAY_SLOT_* and GUSA_* defines to emphasize
> > > > that they are included in TB_FLAGs.  Add aliases for the
> > > > FPSCR and SR bits that are included in TB_FLAGS, so that
> > > > we don't accidentally reassign those bits.
> > > > 
> > > > Fixes: 4da06fb3062 ("target/sh4: Implement prctl_unalign_sigbus")
> > > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/856
> > > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> > > 
> > > I noticed that my sh4 emulations crash randomly with qemu v7.2-rc4.
> > > This happens with all Linux kernel versions. Testing shows that this
> > > patch is responsible. Reverting it fixes the problem.
> > > 
> > 
> > The patch below fixes the problem for me.
> 
> Thanks for the investigation.
> 
> 
> > +++ b/target/sh4/cpu.c
> > @@ -47,7 +47,7 @@ static void superh_cpu_synchronize_from_tb(CPUState *cs,
> >       SuperHCPU *cpu = SUPERH_CPU(cs);
> >       cpu->env.pc = tb_pc(tb);
> > -    cpu->env.flags = tb->flags;
> > +    cpu->env.flags = tb->flags & TB_FLAG_ENVFLAGS_MASK;
> 
> Only this hunk should be necessary.
> 

Confirmed.

Do you plan to send a formal patch, or do you want me to do it ?

Thanks,
Guenter