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

[Anup Patel]

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>

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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