Re: [PATCH 4/4] target/m68k: always call gen_exit_tb() after writes to SR

[Richard Henderson]

On 9/18/22 00:29, Philippe Mathieu-Daudé wrote:
> On 17/9/22 13:25, Mark Cave-Ayland wrote:
> > Any write to SR can change the security state so always call gen_exit_tb() when
> > this occurs. In particular MacOS makes use of andiw/oriw in a few places to
> > handle the switch between user and supervisor mode.
>
> Shouldn't be safer to add the gen_exit_tb() call in gen_set_sr[_im]()?

No.  For halt we need to raise EXCP_HLT.

r~

> > Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> > ---
> >   target/m68k/translate.c | 4 ++++
> >   1 file changed, 4 insertions(+)
> >
> > diff --git a/target/m68k/translate.c b/target/m68k/translate.c
> > index be5561e1e9..892473d01f 100644
> > --- a/target/m68k/translate.c
> > +++ b/target/m68k/translate.c
> > @@ -2373,6 +2373,7 @@ DISAS_INSN(arith_im)
> >           tcg_gen_or_i32(dest, src1, im);
> >           if (with_SR) {
> >               gen_set_sr(s, dest, opsize == OS_BYTE);
> > +            gen_exit_tb(s);
> >           } else {
> >               DEST_EA(env, insn, opsize, dest, &addr);
> >               gen_logic_cc(s, dest, opsize);
> > @@ -2382,6 +2383,7 @@ DISAS_INSN(arith_im)
> >           tcg_gen_and_i32(dest, src1, im);
> >           if (with_SR) {
> >               gen_set_sr(s, dest, opsize == OS_BYTE);
> > +            gen_exit_tb(s);
> >           } else {
> >               DEST_EA(env, insn, opsize, dest, &addr);
> >               gen_logic_cc(s, dest, opsize);
> > @@ -2405,6 +2407,7 @@ DISAS_INSN(arith_im)
> >           tcg_gen_xor_i32(dest, src1, im);
> >           if (with_SR) {
> >               gen_set_sr(s, dest, opsize == OS_BYTE);
> > +            gen_exit_tb(s);
> >           } else {
> >               DEST_EA(env, insn, opsize, dest, &addr);
> >               gen_logic_cc(s, dest, opsize);
> > @@ -4592,6 +4595,7 @@ DISAS_INSN(strldsr)
> >       }
> >       gen_push(s, gen_get_sr(s));
> >       gen_set_sr_im(s, ext, 0);
> > +    gen_exit_tb(s);
> >   }
> >   DISAS_INSN(move_from_sr)