[PATCH 06/11] lib: sbi: Remove MENVCFG hart feature

[Anup Patel]

On Wed, May 4, 2022 at 7:27 AM Atish Patra <atishp at atishpatra.org> wrote:
>
> On Fri, Apr 29, 2022 at 8:52 AM Anup Patel <apatel at ventanamicro.com> wrote:
> >
> > If a hart implements privileged spec v1.12 (or higher) then we can
> > safely assume that menvcfg CSR is present and we don't need MENVCFG
> > as a hart feature.
> >
> > Signed-off-by: Anup Patel <apatel at ventanamicro.com>
> > ---
> >  include/sbi/sbi_hart.h |  6 ++----
> >  lib/sbi/sbi_hart.c     | 32 ++++++++++++--------------------
> >  2 files changed, 14 insertions(+), 24 deletions(-)
> >
> > diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> > index bc6b766..c985674 100644
> > --- a/include/sbi/sbi_hart.h
> > +++ b/include/sbi/sbi_hart.h
> > @@ -32,12 +32,10 @@ enum sbi_hart_features {
> >         SBI_HART_HAS_TIME = (1 << 1),
> >         /** HART has AIA local interrupt CSRs */
> >         SBI_HART_HAS_AIA = (1 << 2),
> > -       /** HART has menvcfg CSR */
> > -       SBI_HART_HAS_MENVCFG = (1 << 3),
> >         /** HART has mstateen CSR **/
> > -       SBI_HART_HAS_SMSTATEEN = (1 << 4),
> > +       SBI_HART_HAS_SMSTATEEN = (1 << 3),
> >         /** HART has SSTC extension implemented in hardware */
> > -       SBI_HART_HAS_SSTC = (1 << 5),
> > +       SBI_HART_HAS_SSTC = (1 << 4),
> >
> >         /** Last index of Hart features*/
> >         SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_SSTC,
> > diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> > index 0fe88cb..5ee5ddd 100644
> > --- a/lib/sbi/sbi_hart.c
> > +++ b/lib/sbi/sbi_hart.c
> > @@ -97,10 +97,8 @@ static void mstatus_init(struct sbi_scratch *scratch)
> >                 mstateen_val |= ((uint64_t)csr_read(CSR_MSTATEEN0H)) << 32;
> >  #endif
> >                 mstateen_val |= SMSTATEEN_STATEN;
> > -               if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MENVCFG))
> > -                       mstateen_val |= SMSTATEEN0_HSENVCFG;
> > -               else
> > -                       mstateen_val &= ~SMSTATEEN0_HSENVCFG;
> > +               mstateen_val |= SMSTATEEN0_HSENVCFG;
> > +
> >                 if (sbi_hart_has_feature(scratch, SBI_HART_HAS_AIA))
> >                         mstateen_val |= (SMSTATEEN0_AIA | SMSTATEEN0_SVSLCT |
> >                                         SMSTATEEN0_IMSIC);
> > @@ -113,7 +111,7 @@ static void mstatus_init(struct sbi_scratch *scratch)
> >  #endif
> >         }
> >
> > -       if (sbi_hart_has_feature(scratch, SBI_HART_HAS_MENVCFG)) {
> > +       if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_12) {
> >                 menvcfg_val = csr_read(CSR_MENVCFG);
> >
> >                 /*
> > @@ -413,9 +411,6 @@ static inline char *sbi_hart_feature_id2string(unsigned long feature)
> >         case SBI_HART_HAS_SSTC:
> >                 fstr = "sstc";
> >                 break;
> > -       case SBI_HART_HAS_MENVCFG:
> > -               fstr = "menvcfg";
> > -               break;
> >         case SBI_HART_HAS_SMSTATEEN:
> >                 fstr = "smstateen";
> >                 break;
> > @@ -616,13 +611,11 @@ __mhpm_skip:
> >             (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_10))
> >                 hfeatures->priv_version = SBI_HART_PRIV_VER_1_11;
> >
> > -       /* Detect if hart has menvcfg CSR */
> > +       /* Detect if hart supports Priv v1.12 */
> >         csr_read_allowed(CSR_MENVCFG, (unsigned long)&trap);
> >         if (!trap.cause &&
> > -           (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_11)) {
> > +           (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_11))
> >                 hfeatures->priv_version = SBI_HART_PRIV_VER_1_12;
> > -               hfeatures->features |= SBI_HART_HAS_MENVCFG;
> > -       }
> >
> >         /* Counter overflow/filtering is not useful without mcounter/inhibit */
> >         if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
> > @@ -644,20 +637,19 @@ __mhpm_skip:
> >         hfeatures->features |= SBI_HART_HAS_AIA;
> >  __aia_skip:
> >
> > -       /**
> > -        * Detect if hart supports stimecmp CSR(Sstc extension) and menvcfg is
> > -        * implemented.
> > -        */
> > -       if (hfeatures->features & SBI_HART_HAS_MENVCFG) {
> > +       /* Detect if hart supports stimecmp CSR(Sstc extension) */
> > +       if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
> >                 csr_read_allowed(CSR_STIMECMP, (unsigned long)&trap);
> >                 if (!trap.cause)
> >                         hfeatures->features |= SBI_HART_HAS_SSTC;
> >         }
> >
> >         /* Detect if hart supports mstateen CSRs */
> > -       val = csr_read_allowed(CSR_MSTATEEN0, (unsigned long)&trap);
> > -       if (!trap.cause)
> > -               hfeatures->features |= SBI_HART_HAS_SMSTATEEN;
> > +       if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
> > +               val = csr_read_allowed(CSR_MSTATEEN0, (unsigned long)&trap);
> > +               if (!trap.cause)
> > +                       hfeatures->features |= SBI_HART_HAS_SMSTATEEN;
> > +       }
> >
> >         return;
> >  }
> > --
> > 2.34.1
> >
>
> Reviewed-by: Atish Patra <atishp at rivosinc.com>

Applied this patch to the riscv/opensbi repo

Regards,
Anup

>
> --
> Regards,
> Atish