Hi Fabien,
> On December 7, 2015 at 12:35 PM Fabien Chouteau <chout...@adacore.com> wrote:
>
>
> Hello Alex,
>
> Thanks for your patch! I have a couple of comments.
>
> On 12/04/2015 04:01 PM, Alex Zuepke wrote:
> > LEON3 allows the CASA instruction to be used from user space
> > if the ASI is set to 0xa (user data).
> >
> > Signed-off-by: Alex Zuepke <a...@sysgo.de>
> > ---
> > target-sparc/translate.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/target-sparc/translate.c b/target-sparc/translate.c
> > index 41a3319..63440dd 100644
> > --- a/target-sparc/translate.c
> > +++ b/target-sparc/translate.c
> > @@ -5097,7 +5097,8 @@ static void disas_sparc_insn(DisasContext * dc,
> > unsigned int insn)
> > if (IS_IMM) {
> > goto illegal_insn;
> > }
> > - if (!supervisor(dc)) {
> > + /* LEON3 allows CASA from user space with ASI 0xa */
>
> Since this is a LEON3 specific feature, when you check the ASI you
> should also check CPU_FEATURE_CASA.
>
> > + if ((GET_FIELD(insn, 19, 26) != 0xa) &&
> > !supervisor(dc)) {
> > goto priv_insn;
> > }
>
> That would give you something like this:
>
> diff --git a/target-sparc/translate.c b/target-sparc/translate.c
> index 41a3319..b93faea 100644
> --- a/target-sparc/translate.c
> +++ b/target-sparc/translate.c
> @@ -2463,6 +2463,9 @@ static void gen_faligndata(TCGv dst, TCGv gsr, TCGv s1,
> TCGv s2)
> }
> #endif
>
> +#define IU_FEATURE(dc, FEATURE) \
> + (((dc)->def->features & CPU_FEATURE_ ## FEATURE))
> +
> #define CHECK_IU_FEATURE(dc, FEATURE) \
> if (!((dc)->def->features & CPU_FEATURE_ ## FEATURE)) \
> goto illegal_insn;
> @@ -5097,7 +5100,11 @@ static void disas_sparc_insn(DisasContext * dc,
> unsigned int insn)
> if (IS_IMM) {
> goto illegal_insn;
> }
> - if (!supervisor(dc)) {
> +
> + /* LEON3 allows CASA from user space with ASI 0xa */
> + if (!((IU_FEATURE(dc, CASA) &&
> + (GET_FIELD(insn, 19, 26) == 0xa))
> + || supervisor(dc))) {
> goto priv_insn;
> }
> #endif
>
>
> to be tested of course ;)
>
> Regards,
The check for the CASA feature on SPARC v8 is already in the existng code,
just 3 lines above the second hunk in the patch:
#if !defined(CONFIG_USER_ONLY) || defined(TARGET_SPARC64)
case 0x3c: /* V9 or LEON3 casa */
#ifndef TARGET_SPARC64
CHECK_IU_FEATURE(dc, CASA);
if (IS_IMM) {
goto illegal_insn;
}
if (!supervisor(dc)) {
goto priv_insn;
}
...
So I don't think it's necessary to check it again.
Best regards
Alex
