[PATCH 2/2] lib: sbi_hsm: Fix sbi_hsm_hart_start() for platform with hart hotplug

[Anup Patel]

On Mon, Mar 20, 2023 at 9:29 PM Anup Patel <apatel at ventanamicro.com> wrote:
>
> It possible that a platform supports hart hotplug (i.e. both hart_start
> and hart_stop callbacks available) and all harts are start simultaneously
> at platform boot-time. In this situation, the sbi_hsm_hart_start() will
> call hsm_device_hart_start() for secondary harts at platform boot-time
> which will fail because secondary harts were already started.
>
> To fix above, we call hsm_device_hart_start() from sbi_hsm_hart_start()
> only when entry_count is same as init_count for the secondary hart.
>
> Signed-off-by: Anup Patel <apatel at ventanamicro.com>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

> ---
>  lib/sbi/sbi_hsm.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/lib/sbi/sbi_hsm.c b/lib/sbi/sbi_hsm.c
> index 16e3846..b261410 100644
> --- a/lib/sbi/sbi_hsm.c
> +++ b/lib/sbi/sbi_hsm.c
> @@ -301,7 +301,7 @@ int sbi_hsm_hart_start(struct sbi_scratch *scratch,
>                        const struct sbi_domain *dom,
>                        u32 hartid, ulong saddr, ulong smode, ulong arg1)
>  {
> -       unsigned long init_count;
> +       unsigned long init_count, entry_count;
>         unsigned int hstate;
>         struct sbi_scratch *rscratch;
>         struct sbi_hsm_data *hdata;
> @@ -325,6 +325,8 @@ int sbi_hsm_hart_start(struct sbi_scratch *scratch,
>                 return SBI_EINVAL;
>
>         init_count = sbi_init_count(hartid);
> +       entry_count = sbi_entry_count(hartid);
> +
>         rscratch->next_arg1 = arg1;
>         rscratch->next_addr = saddr;
>         rscratch->next_mode = smode;
> @@ -350,7 +352,7 @@ int sbi_hsm_hart_start(struct sbi_scratch *scratch,
>                 goto err;
>         }
>
> -       if (hsm_device_has_hart_hotplug() ||
> +       if ((hsm_device_has_hart_hotplug() && (entry_count == init_count)) ||
>            (hsm_device_has_hart_secondary_boot() && !init_count)) {
>                 rc = hsm_device_hart_start(hartid, scratch->warmboot_addr);
>         } else {
> --
> 2.34.1
>