[PATCH v3 3/5] lib: sbi: Detect and print MHPM counters at boot-time

[Atish Patra]

On Thu, Aug 27, 2020 at 8:41 PM Anup Patel <anup.patel at wdc.com> wrote:
>
> A RISC-V platform can leave unimplemented MHPM counters hard-wired
> to zero. We extend hart_detect_features() to detect MHPM counters
> which are accessible and not hard-wired to zero. We also print
> number of available MHPM counters as part of boot prints.
>
> Signed-off-by: Anup Patel <anup.patel at wdc.com>
> ---
>  include/sbi/sbi_hart.h |  1 +
>  lib/sbi/sbi_hart.c     | 17 +++++++++++++++++
>  lib/sbi/sbi_init.c     |  1 +
>  3 files changed, 19 insertions(+)
>
> diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h
> index c2ea686..1e1eb67 100644
> --- a/include/sbi/sbi_hart.h
> +++ b/include/sbi/sbi_hart.h
> @@ -35,6 +35,7 @@ static inline ulong sbi_hart_expected_trap_addr(void)
>         return (ulong)sbi_hart_expected_trap;
>  }
>
> +unsigned int sbi_hart_mhpm_count(struct sbi_scratch *scratch);
>  void sbi_hart_delegation_dump(struct sbi_scratch *scratch);
>  unsigned int sbi_hart_pmp_count(struct sbi_scratch *scratch);
>  int sbi_hart_pmp_get(struct sbi_scratch *scratch, unsigned int n,
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index 8f31d58..2211c3c 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -28,6 +28,7 @@ void (*sbi_hart_expected_trap)(void) = &__sbi_expected_trap;
>  struct hart_features {
>         unsigned long features;
>         unsigned int pmp_count;
> +       unsigned int mhpm_count;
>  };
>  static unsigned long hart_features_offset;
>
> @@ -135,6 +136,14 @@ void sbi_hart_delegation_dump(struct sbi_scratch *scratch)
>  #endif
>  }
>
> +unsigned int sbi_hart_mhpm_count(struct sbi_scratch *scratch)
> +{
> +       struct hart_features *hfeatures =
> +                       sbi_scratch_offset_ptr(scratch, hart_features_offset);
> +
> +       return hfeatures->mhpm_count;
> +}
> +
>  unsigned int sbi_hart_pmp_count(struct sbi_scratch *scratch)
>  {
>         struct hart_features *hfeatures =
> @@ -339,6 +348,7 @@ static void hart_detect_features(struct sbi_scratch *scratch)
>         hfeatures = sbi_scratch_offset_ptr(scratch, hart_features_offset);
>         hfeatures->features = 0;
>         hfeatures->pmp_count = 0;
> +       hfeatures->mhpm_count = 0;
>
>  #define __check_csr(__csr, __rdonly, __wrval, __field, __skip) \
>         val = csr_read_allowed(__csr, (ulong)&trap);                    \
> @@ -382,6 +392,13 @@ static void hart_detect_features(struct sbi_scratch *scratch)
>         __check_csr_64(CSR_PMPADDR0, 0, PMP_ADDR_MASK, pmp_count, __pmp_skip);
>  __pmp_skip:
>
> +       /* Detect number of MHPM counters */
> +       __check_csr(CSR_MHPMCOUNTER3, 0, 1UL, mhpm_count, __mhpm_skip);
> +       __check_csr_4(CSR_MHPMCOUNTER4, 0, 1UL, mhpm_count, __mhpm_skip);
> +       __check_csr_8(CSR_MHPMCOUNTER8, 0, 1UL, mhpm_count, __mhpm_skip);
> +       __check_csr_16(CSR_MHPMCOUNTER16, 0, 1UL, mhpm_count, __mhpm_skip);
> +__mhpm_skip:
> +
>  #undef __check_csr_64
>  #undef __check_csr_32
>  #undef __check_csr_16
> diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
> index c438eaa..e1a1d96 100644
> --- a/lib/sbi/sbi_init.c
> +++ b/lib/sbi/sbi_init.c
> @@ -70,6 +70,7 @@ static void sbi_boot_prints(struct sbi_scratch *scratch, u32 hartid)
>         sbi_hart_get_features_str(scratch, str, sizeof(str));
>         sbi_printf("BOOT HART Features  : %s\n", str);
>         sbi_printf("BOOT HART PMP Count : %d\n", sbi_hart_pmp_count(scratch));
> +       sbi_printf("BOOT HART MHPM Count: %d\n", sbi_hart_mhpm_count(scratch));
>
>         /* Firmware details */
>         sbi_printf("Firmware Base       : 0x%lx\n", scratch->fw_start);
> --
> 2.25.1
>
>
> --
> opensbi mailing list
> opensbi at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/opensbi



Reviewed-by: Atish Patra <atish.patra at wdc.com>
-- 
Regards,
Atish