[PATCH 3/3] lib: sbi: Fix tval and tinst for sbi_get_insn()

[Anup Patel]

On Sat, Jun 18, 2022 at 11:28 AM Anup Patel <anup at brainfault.org> wrote:
>
> On Thu, Jun 9, 2022 at 12:38 PM dramforever <dramforever at live.com> wrote:
> >
> > We should not change trap->tval to mepc because mtval already points to
> > the faulting portion of the emulated instruction fetch, which is also
> > what stval is expected to be.
> >
> > In addition, htinst is only allowed to be zero for instruction access
> > faults or page faults, and is only allowed to be zero or a
> > psuedoinstruction for instruction guest-page faults. Fix trap->tinst for
> > these cases.
> >
> > Signed-off-by: dramforever <dramforever at live.com>
>
> Looks good to me.
>
> Reviewed-by: Anup Patel <anup at brainfault.org>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

>
> Regards,
> Anup
>
> > ---
> >  lib/sbi/sbi_unpriv.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/lib/sbi/sbi_unpriv.c b/lib/sbi/sbi_unpriv.c
> > index 73b530c..9a34a71 100644
> > --- a/lib/sbi/sbi_unpriv.c
> > +++ b/lib/sbi/sbi_unpriv.c
> > @@ -149,15 +149,17 @@ ulong sbi_get_insn(ulong mepc, struct sbi_trap_info *trap)
> >         switch (trap->cause) {
> >         case CAUSE_LOAD_ACCESS:
> >                 trap->cause = CAUSE_FETCH_ACCESS;
> > -               trap->tval = mepc;
> > +               trap->tinst = 0UL;
> >                 break;
> >         case CAUSE_LOAD_PAGE_FAULT:
> >                 trap->cause = CAUSE_FETCH_PAGE_FAULT;
> > -               trap->tval = mepc;
> > +               trap->tinst = 0UL;
> >                 break;
> >         case CAUSE_LOAD_GUEST_PAGE_FAULT:
> >                 trap->cause = CAUSE_FETCH_GUEST_PAGE_FAULT;
> > -               trap->tval = mepc;
> > +               if (trap->tinst != INSN_PSEUDO_VS_LOAD &&
> > +                   trap->tinst != INSN_PSEUDO_VS_STORE)
> > +                       trap->tinst = 0UL;
> >                 break;
> >         default:
> >                 break;
> > --
> > 2.36.0
> >
> >
> > --
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> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi