[PATCH 2/7] include: sbi: Add sbi_regs_prev_xlen

[Anup Patel]

On Tue, Feb 10, 2026 at 3:12 PM Bo Gan <ganboing at gmail.com> wrote:
>
> sbi_regs_prev_xlen reports the xlen of previous mode by decoding
> from multiple CSRs including mstatus/hstatus/vsstatus
>
> Signed-off-by: Bo Gan <ganboing at gmail.com>

LGTM.

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

Regards,
Anup

> ---
>  include/sbi/sbi_trap.h | 58 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 58 insertions(+)
>
> diff --git a/include/sbi/sbi_trap.h b/include/sbi/sbi_trap.h
> index 731a0c98..4ef672f4 100644
> --- a/include/sbi/sbi_trap.h
> +++ b/include/sbi/sbi_trap.h
> @@ -273,6 +273,64 @@ static inline int sbi_mstatus_prev_mode(unsigned long mstatus)
>         return (mstatus & MSTATUS_MPP) >> MSTATUS_MPP_SHIFT;
>  }
>
> +#if __riscv_xlen == 32
> +static inline int sbi_regs_prev_xlen(const struct sbi_trap_regs *regs)
> +{
> +       return __riscv_xlen;
> +}
> +#else
> +static inline int sbi_mstatus_sxl(unsigned long mstatus)
> +{
> +       return (mstatus & MSTATUS_SXL) >> MSTATUS_SXL_SHIFT;
> +}
> +
> +static inline int sbi_mstatus_uxl(unsigned long mstatus)
> +{
> +       return (mstatus & MSTATUS_UXL) >> MSTATUS_UXL_SHIFT;
> +}
> +
> +static inline int sbi_hstatus_vsxl(unsigned long hstatus)
> +{
> +       return (hstatus & HSTATUS_VSXL) >> HSTATUS_VSXL_SHIFT;
> +}
> +
> +static inline int sbi_regs_prev_xlen(const struct sbi_trap_regs *regs)
> +{
> +       unsigned long hstatus, vsstatus;
> +
> +       if (!sbi_regs_from_virt(regs)) {
> +               switch (sbi_mstatus_prev_mode(regs->mstatus)) {
> +               case PRV_M:
> +                       return __riscv_xlen;
> +               case PRV_S:
> +                       return MXL_TO_XLEN(sbi_mstatus_sxl(regs->mstatus));
> +               case PRV_U:
> +                       return MXL_TO_XLEN(sbi_mstatus_uxl(regs->mstatus));
> +               default:
> +                       __builtin_unreachable();
> +               }
> +       }
> +
> +       /* V=1, Check HSXLEN first */
> +       if (sbi_mstatus_sxl(regs->mstatus) < MXL_XLEN_64)
> +               return 32;
> +
> +       hstatus = csr_read(CSR_HSTATUS);
> +       /* Check VSXLEN */
> +       if (sbi_hstatus_vsxl(hstatus) < MXL_XLEN_64)
> +               return 32;
> +
> +       vsstatus = csr_read(CSR_VSSTATUS);
> +       switch (sbi_mstatus_prev_mode(regs->mstatus)) {
> +               case PRV_S:
> +                       return MXL_TO_XLEN(sbi_hstatus_vsxl(hstatus));
> +               case PRV_U:
> +                       return MXL_TO_XLEN(sbi_mstatus_uxl(vsstatus));
> +       }
> +       __builtin_unreachable();
> +}
> +#endif
> +
>  int sbi_trap_redirect(struct sbi_trap_regs *regs,
>                       const struct sbi_trap_info *trap);
>
> --
> 2.34.1
>