[PATCH 3/4] lib: sbi: Improve the code of privilege mode and extensions detection

[Anup Patel]

On Thu, Sep 7, 2023 at 2:57 PM Yong-Xuan Wang <yongxuan.wang at sifive.com> wrote:
>
> We can enhance the code by creating 2 unified interface with macro  for
> privilege mode and extensions detection, which relies on supported
> privilege modes and CSRs.
>
> Signed-off-by: Yong-Xuan Wang <yongxuan.wang at sifive.com>

Looks good to me.

Reviewed-by: Anup Patel <anup at brainfault.org>

Regards,
Anup

> ---
>  lib/sbi/sbi_hart.c | 90 ++++++++++++++++++++--------------------------
>  1 file changed, 39 insertions(+), 51 deletions(-)
>
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index 21af2b5..b7ca0e6 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -722,6 +722,7 @@ static int hart_detect_features(struct sbi_scratch *scratch)
>         hfeatures->extensions = 0;
>         hfeatures->pmp_count = 0;
>         hfeatures->mhpm_mask = 0;
> +       hfeatures->priv_version = SBI_HART_PRIV_VER_UNKNOWN;
>
>  #define __check_hpm_csr(__csr, __mask)                                           \
>         oldval = csr_read_allowed(__csr, (ulong)&trap);                   \
> @@ -814,67 +815,54 @@ __pmp_skip:
>  #undef __check_csr_2
>  #undef __check_csr
>
> -       /* Detect if hart supports Priv v1.10 */
> -       val = csr_read_allowed(CSR_MCOUNTEREN, (unsigned long)&trap);
> -       if (!trap.cause)
> -               hfeatures->priv_version = SBI_HART_PRIV_VER_1_10;
>
> -       /* Detect if hart supports Priv v1.11 */
> -       val = csr_read_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap);
> -       if (!trap.cause &&
> -           (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_10))
> -               hfeatures->priv_version = SBI_HART_PRIV_VER_1_11;
> +#define __check_priv(__csr, __base_priv, __priv)                       \
> +       val = csr_read_allowed(__csr, (ulong)&trap);                    \
> +       if (!trap.cause && (hfeatures->priv_version >= __base_priv)) {  \
> +               hfeatures->priv_version = __priv;                       \
> +       }                                                               \
>
> +       /* Detect if hart supports Priv v1.10 */
> +       __check_priv(CSR_MCOUNTEREN,
> +                    SBI_HART_PRIV_VER_UNKNOWN, SBI_HART_PRIV_VER_1_10);
> +       /* Detect if hart supports Priv v1.11 */
> +       __check_priv(CSR_MCOUNTINHIBIT,
> +                    SBI_HART_PRIV_VER_1_10, SBI_HART_PRIV_VER_1_11);
>         /* 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_12;
> +       __check_priv(CSR_MENVCFG,
> +                    SBI_HART_PRIV_VER_1_11, SBI_HART_PRIV_VER_1_12);
>
> -       /* Counter overflow/filtering is not useful without mcounter/inhibit */
> -       if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_11) {
> -               /* Detect if hart supports sscofpmf */
> -               csr_read_allowed(CSR_SCOUNTOVF, (unsigned long)&trap);
> -               if (!trap.cause)
> -                       __sbi_hart_update_extension(hfeatures,
> -                                       SBI_HART_EXT_SSCOFPMF, true);
> -       }
> +#undef __check_priv_csr
>
> -       /* Detect if hart supports time CSR */
> -       csr_read_allowed(CSR_TIME, (unsigned long)&trap);
> -       if (!trap.cause)
> -               __sbi_hart_update_extension(hfeatures,
> -                                       SBI_HART_EXT_ZICNTR, true);
> +#define __check_ext_csr(__base_priv, __csr, __ext)                     \
> +       if (hfeatures->priv_version >= __base_priv) {                   \
> +               csr_read_allowed(__csr, (ulong)&trap);                  \
> +               if (!trap.cause)                                        \
> +                       __sbi_hart_update_extension(hfeatures,          \
> +                                                   __ext, true);       \
> +       }                                                               \
>
> +       /* Counter overflow/filtering is not useful without mcounter/inhibit */
> +       /* Detect if hart supports sscofpmf */
> +       __check_ext_csr(SBI_HART_PRIV_VER_1_11,
> +                       CSR_SCOUNTOVF, SBI_HART_EXT_SSCOFPMF);
> +       /* Detect if hart supports time CSR */
> +       __check_ext_csr(SBI_HART_PRIV_VER_UNKNOWN,
> +                       CSR_TIME, SBI_HART_EXT_ZICNTR);
>         /* Detect if hart has AIA local interrupt CSRs */
> -       csr_read_allowed(CSR_MTOPI, (unsigned long)&trap);
> -       if (!trap.cause)
> -               __sbi_hart_update_extension(hfeatures,
> -                                       SBI_HART_EXT_SMAIA, true);
> -
> +       __check_ext_csr(SBI_HART_PRIV_VER_UNKNOWN,
> +                       CSR_MTOPI, SBI_HART_EXT_SMAIA);
>         /* 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)
> -                       __sbi_hart_update_extension(hfeatures,
> -                                       SBI_HART_EXT_SSTC, true);
> -       }
> -
> +       __check_ext_csr(SBI_HART_PRIV_VER_1_12,
> +                       CSR_STIMECMP, SBI_HART_EXT_SSTC);
>         /* Detect if hart supports mstateen CSRs */
> -       if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
> -               val = csr_read_allowed(CSR_MSTATEEN0, (unsigned long)&trap);
> -               if (!trap.cause)
> -                       __sbi_hart_update_extension(hfeatures,
> -                                       SBI_HART_EXT_SMSTATEEN, true);
> -       }
> -
> +       __check_ext_csr(SBI_HART_PRIV_VER_1_12,
> +                       CSR_MSTATEEN0, SBI_HART_EXT_SMSTATEEN);
>         /* Detect if hart supports smcntrpmf */
> -       if (hfeatures->priv_version >= SBI_HART_PRIV_VER_1_12) {
> -               csr_read_allowed(CSR_MCYCLECFG, (unsigned long)&trap);
> -               if (!trap.cause)
> -                       __sbi_hart_update_extension(hfeatures,
> -                                       SBI_HART_EXT_SMCNTRPMF, true);
> -       }
> +       __check_ext_csr(SBI_HART_PRIV_VER_1_12,
> +                       CSR_MCYCLECFG, SBI_HART_EXT_SMCNTRPMF);
> +
> +#undef __check_ext_csr
>
>         /* Let platform populate extensions */
>         rc = sbi_platform_extensions_init(sbi_platform_thishart_ptr(),
> --
> 2.17.1
>
>
> --
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