[PATCH 1/3] dt-bindings: riscv: Add Supm extension description

[Conor Dooley]

On Fri, Jan 16, 2026 at 10:10:31AM +0800, Guodong Xu wrote:
> Add description for the Supm extension. Supm indicates support for pointer
> masking in user mode. Supm is mandatory for RVA23S64.
> 
> The Supm extension is ratified in commit d70011dde6c2 ("Update to ratified
> state") of riscv-j-extension.
> 
> Signed-off-by: Guodong Xu <guodong at riscstar.com>
> ---
>  Documentation/devicetree/bindings/riscv/extensions.yaml | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
> index 4ffd61926505..1922dff03787 100644
> --- a/Documentation/devicetree/bindings/riscv/extensions.yaml
> +++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
> @@ -262,6 +262,23 @@ properties:
>              ratified in RISC-V Profiles Version 1.0, with commit b1d806605f87
>              ("Updated to ratified state.")
>  
> +        - const: supm
> +          description: |
> +            The standard Supm extension for pointer masking support in user
> +            mode (U-mode) as ratified at commit d70011dde6c2 ("Update to
> +            ratified state") of riscv-j-extension.
> +
> +            Supm represents a combination of underlying hardware capability
> +            (Smnpm or Ssnpm), U-mode consumer privilege level, and M/S-mode

Should we therefore make this require that Smnpm or Ssnpm are present?

> +            software configuration that enables pointer masking for U-mode.
> +
> +            DO NOT include this property in device trees targeting privileged
> +            system software (S-mode or M-mode).
> +
> +            This property is only appropriate in device trees provided to
> +            U-mode software where the next-higher-privilege-mode supports
> +            Smnpm or Ssnpm and enables it for U-mode.
> +
>          - const: svade
>            description: |
>              The standard Svade supervisor-level extension for SW-managed PTE A/D
> 
> -- 
> 2.43.0
> 
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