[PATCH v2 11/13] dt-bindings: riscv: Add Supm extension description

[Conor Dooley]

On Mon, Dec 22, 2025 at 09:04:21PM +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.
> 
> Supm depends on either Smnpm or Ssnpm, so add a schema check to enforce
> this dependency.
> 
> Signed-off-by: Guodong Xu <guodong at riscstar.com>
> ---
> v2: New patch.
> ---
>  Documentation/devicetree/bindings/riscv/extensions.yaml | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/riscv/extensions.yaml b/Documentation/devicetree/bindings/riscv/extensions.yaml
> index 1066b7e65dab89704dbac449db4aa5605c95b9d3..4997f533b2c0defad88fd59413a6885b5b9e109a 100644
> --- a/Documentation/devicetree/bindings/riscv/extensions.yaml
> +++ b/Documentation/devicetree/bindings/riscv/extensions.yaml
> @@ -267,6 +267,12 @@ 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 as ratified at commit d70011dde6c2 ("Update to ratified state")
> +            of riscv-j-extension.

I'm not yet convinced that this makes sense as this describes how the
consumer of the devicetree behaves not the hardware. How the hardware
behaves is already described by smnpn and ssnpm. I'd really like to
see some commentary from Samuel Holland on either this or on
https://lore.kernel.org/all/20251222-dimmer-wooing-db29fe925498@spud/
before I'd be happy with this change.

> +
>          - const: svade
>            description: |
>              The standard Svade supervisor-level extension for SW-managed PTE A/D
> @@ -892,6 +898,16 @@ properties:
>                  const: shvstvecd
>              - contains:
>                  const: ssstateen
> +      # Supm depends on either Smnpm or Ssnpm
> +      - if:
> +          contains:
> +            const: supm
> +        then:
> +          anyOf:
> +            - contains:
> +                const: smnpm
> +            - contains:
> +                const: ssnpm
>        # Zcb depends on Zca
>        - if:
>            contains:
> 
> -- 
> 2.43.0
> 
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