[PATCH 8/8] lib: sbi_hart: properly reset Ssstateen

[Anup Patel]

On Tue, Apr 15, 2025 at 8:13 PM Radim Krčmář <rkrcmar at ventanamicro.com> wrote:
>
> sstateen* and hstateen* CSRs must be zeroed by M-mode if the mstateen*
> registers are missing, to avoid security issues.
>
> Signed-off-by: Radim Krčmář <rkrcmar at ventanamicro.com>
> ---
>  lib/sbi/sbi_hart.c | 16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c
> index bc0a73d1298d..0f61e9cd1c98 100644
> --- a/lib/sbi/sbi_hart.c
> +++ b/lib/sbi/sbi_hart.c
> @@ -114,12 +114,22 @@ static void mstatus_init(struct sbi_scratch *scratch)
>                 csr_write64(CSR_MSTATEEN1, SMSTATEEN_STATEN);
>                 csr_write64(CSR_MSTATEEN2, SMSTATEEN_STATEN);
>                 csr_write64(CSR_MSTATEEN3, SMSTATEEN_STATEN);
> +       }
>
> -               if (misa_extension('S'))
> +       if (sbi_hart_has_extension(scratch, SBI_HART_EXT_SMSTATEEN) ||
> +           sbi_hart_has_extension(scratch, SBI_HART_EXT_SSSTATEEN)) {

This should only check SSSTATEEEN.

> +               if (misa_extension('S')) {
>                         csr_write(CSR_SSTATEEN0, 0);
> -
> -               if (misa_extension('H'))
> +                       csr_write(CSR_SSTATEEN1, 0);
> +                       csr_write(CSR_SSTATEEN2, 0);
> +                       csr_write(CSR_SSTATEEN3, 0);
> +               }
> +               if (misa_extension('H')) {
>                         csr_write64(CSR_HSTATEEN0, (uint64_t)0);
> +                       csr_write64(CSR_HSTATEEN1, (uint64_t)0);
> +                       csr_write64(CSR_HSTATEEN2, (uint64_t)0);
> +                       csr_write64(CSR_HSTATEEN3, (uint64_t)0);
> +               }
>         }
>
>         if (sbi_hart_priv_version(scratch) >= SBI_HART_PRIV_VER_1_12) {
> --
> 2.48.1
>
>
> --
> opensbi mailing list
> opensbi at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/opensbi

Otherwise, LGTM.

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

Regards,
Anup