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

[Atish Patra]

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>

-- 
Regards,
Atish