[PATCH v2 2/4] lib: sbi: fwft: add support for SBI_FWFT_MISALIGNED_EXC_DELEG

[Anup Patel]

On Tue, Jun 18, 2024 at 9:23 PM Anup Patel <anup at brainfault.org> wrote:
>
> On Mon, Jun 17, 2024 at 9:11 PM Clément Léger <cleger at rivosinc.com> wrote:
> >
> > Add support for SBI_FWFT_MISALIGNED_EXC_DELEG withing FWFT support. This
> > support allows to delegate misaligned accesses traps.
> >
> > Signed-off-by: Clément Léger <cleger at rivosinc.com>
> > ---
> >  lib/sbi/sbi_fwft.c | 39 ++++++++++++++++++++++++++++++++++++++-
> >  lib/sbi/sbi_hsm.c  |  3 +++
> >  2 files changed, 41 insertions(+), 1 deletion(-)
> >
> > diff --git a/lib/sbi/sbi_fwft.c b/lib/sbi/sbi_fwft.c
> > index b302b5d..289a344 100644
> > --- a/lib/sbi/sbi_fwft.c
> > +++ b/lib/sbi/sbi_fwft.c
> > @@ -32,6 +32,8 @@ static unsigned long fwft_ptr_offset;
> >  #define fwft_set_hart_state_ptr(__scratch, __phs)                      \
> >         sbi_scratch_write_type((__scratch), void *, fwft_ptr_offset, (__phs))
> >
> > +#define MIS_DELEG (1UL << CAUSE_MISALIGNED_LOAD | 1UL << CAUSE_MISALIGNED_STORE)
> > +
> >  struct fwft_config;
> >
> >  struct fwft_feature {
> > @@ -71,6 +73,33 @@ static bool fwft_is_defined_feature(enum sbi_fwft_feature_t feature)
> >         return false;
> >  }
> >
> > +static int fwft_misaligned_delegation_supported(struct fwft_config *conf)
> > +{
> > +       if (!misa_extension('S'))
> > +               return SBI_ENOTSUPP;
> > +
> > +       return SBI_OK;
> > +}
> > +
> > +static int fwft_set_misaligned_delegation(struct fwft_config *conf,
> > +                                        unsigned long value)
> > +{
> > +       if (value)
> > +               csr_set(CSR_MEDELEG, MIS_DELEG);
> > +       else
> > +               csr_clear(CSR_MEDELEG, MIS_DELEG);
> > +
> > +       return SBI_OK;
> > +}
> > +
> > +static int fwft_get_misaligned_delegation(struct fwft_config *conf,
> > +                                        unsigned long *value)
> > +{
> > +       *value = (csr_read(CSR_MEDELEG) & MIS_DELEG) != 0;
> > +
> > +       return SBI_OK;
> > +}
> > +
> >  static struct fwft_config* get_feature_config(enum sbi_fwft_feature_t feature)
> >  {
> >         int i;
> > @@ -148,7 +177,15 @@ int sbi_fwft_get(enum sbi_fwft_feature_t feature, unsigned long *out_val)
> >         return conf->feature->get(conf, out_val);
> >  }
> >
> > -static const struct fwft_feature features[] = {};
> > +static const struct fwft_feature features[] =
> > +{
> > +       {
> > +               .id = SBI_FWFT_MISALIGNED_EXC_DELEG,
> > +               .supported = fwft_misaligned_delegation_supported,
> > +               .set = fwft_set_misaligned_delegation,
> > +               .get = fwft_get_misaligned_delegation,
> > +       },
> > +};
> >
> >  int sbi_fwft_init(struct sbi_scratch *scratch, bool cold_boot)
> >  {
> > diff --git a/lib/sbi/sbi_hsm.c b/lib/sbi/sbi_hsm.c
> > index be48d64..47edab2 100644
> > --- a/lib/sbi/sbi_hsm.c
> > +++ b/lib/sbi/sbi_hsm.c
> > @@ -44,6 +44,7 @@ struct sbi_hsm_data {
> >         unsigned long suspend_type;
> >         unsigned long saved_mie;
> >         unsigned long saved_mip;
> > +       unsigned long saved_hedeleg;
> >         atomic_t start_ticket;
> >  };
> >
> > @@ -417,6 +418,7 @@ void __sbi_hsm_suspend_non_ret_save(struct sbi_scratch *scratch)
> >
> >         hdata->saved_mie = csr_read(CSR_MIE);
> >         hdata->saved_mip = csr_read(CSR_MIP) & (MIP_SSIP | MIP_STIP);
> > +       hdata->saved_hedeleg = csr_read(CSR_HEDELEG);
> >  }
> >
> >  static void __sbi_hsm_suspend_non_ret_restore(struct sbi_scratch *scratch)
> > @@ -424,6 +426,7 @@ static void __sbi_hsm_suspend_non_ret_restore(struct sbi_scratch *scratch)
> >         struct sbi_hsm_data *hdata = sbi_scratch_offset_ptr(scratch,
> >                                                             hart_data_offset);
> >
> > +       csr_write(CSR_HEDELEG, hdata->saved_hedeleg);
>
> These changes in sbi_hsm.c look like a separate patch.
> Why is it here ?

I think you meant to save/restore medeleg here. right ?

Regards,
Anup

>
> >         csr_write(CSR_MIE, hdata->saved_mie);
> >         csr_set(CSR_MIP, (hdata->saved_mip & (MIP_SSIP | MIP_STIP)));
> >  }
> > --
> > 2.45.2
> >
> >
> > --
> > opensbi mailing list
> > opensbi at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/opensbi
>
> Regards,
> Anup