[PATCH] lib: sbi: Fix sbi_pmu_exit() for systems not having MCOUNTINHIBIT csr

[Anup Patel]

On Sun, Jul 11, 2021 at 2:33 PM Anup Patel <anup.patel at wdc.com> wrote:
>
> The sbi_pmu_exit() crashes on systems not having MCOUNTINHIBIT csr
> so to fix this we check SBI_HART_HAS_MCOUNTINHIBIT feature in
> sbi_pmu_exit() and do nothing if it is not available.
>
> Fixes: 13d40f21d588 ("lib: sbi: Add PMU support")
> Signed-off-by: Anup Patel <anup.patel at wdc.com>

Merging this patch immediately, because SBI HSM stop, SBI shutdown,
and SBI reboot is broken due to sbi_pmu_exit() crashing.

Applied this patch to the riscv/opensbi repo.

Regards,
Anup

> ---
>  lib/sbi/sbi_pmu.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/lib/sbi/sbi_pmu.c b/lib/sbi/sbi_pmu.c
> index 4092e6f..c276a46 100644
> --- a/lib/sbi/sbi_pmu.c
> +++ b/lib/sbi/sbi_pmu.c
> @@ -583,6 +583,10 @@ void sbi_pmu_exit(struct sbi_scratch *scratch)
>  {
>         u32 hartid = current_hartid();
>
> +       /* SBI PMU is not supported if mcountinhibit is not available */
> +       if (!sbi_hart_has_feature(scratch, SBI_HART_HAS_MCOUNTINHIBIT))
> +               return;
> +
>         csr_write(CSR_MCOUNTINHIBIT, 0xFFFFFFF8);
>         csr_write(CSR_MCOUNTEREN, 7);
>         pmu_reset_event_map(hartid);
> --
> 2.25.1
>