Re: [PATCH v3 15/66] target/sh4: Implement do_unaligned_access for user-only

[Richard Henderson]

On 8/19/21 5:46 AM, Peter Maydell wrote:
> On Wed, 18 Aug 2021 at 20:26, Richard Henderson
> <richard.henderson@linaro.org> wrote:
> > Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> > ---
> >   linux-user/sh4/cpu_loop.c | 8 ++++++++
> >   target/sh4/cpu.c          | 2 +-
> >   target/sh4/op_helper.c    | 3 ---
> >   3 files changed, 9 insertions(+), 4 deletions(-)
> >
> > diff --git a/linux-user/sh4/cpu_loop.c b/linux-user/sh4/cpu_loop.c
> > index 222ed1c670..21d97250a8 100644
> > --- a/linux-user/sh4/cpu_loop.c
> > +++ b/linux-user/sh4/cpu_loop.c
> > @@ -71,6 +71,14 @@ void cpu_loop(CPUSH4State *env)
> >               info._sifields._sigfault._addr = env->tea;
> >               queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
> >               break;
> > +        case 0xe0:
> > +        case 0x100:
> > +            info.si_signo = TARGET_SIGBUS;
> > +            info.si_errno = 0;
> > +            info.si_code = TARGET_BUS_ADRALN;
> > +            info._sifields._sigfault._addr = env->tea;
> > +            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
> > +            break;
> >           case EXCP_ATOMIC:
> >               cpu_exec_step_atomic(cs);
> >               arch_interrupt = false;
>
> Doesn't this have to wait until after the later patches in the
> series that implement the "actually don't worry about alignment
> on most sh4 load/stores" ?

Hmm.  I don't think that helps.  The only thing that delaying this patch would do is hit 
the assert in cpu_unaligned_access() due to an alignment fault occurring but not having 
the do_unaligned_access hook set.

I think the real requirement is that the tcg/i386 patch that enforces the alignment is 
delayed until after all of the prctl patches.


r~