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@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
+            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

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@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
> 

On Fri, Jan 23, 2026 at 2:52 AM Conor Dooley <conor@kernel.org> wrote:
>
> 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@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?

I'm not sure. Would U-mode DTBs typically omit the privileged extensions like
Smnpm/Ssnpm, making such a dependency impractical?

-Guodong

>
> > +            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
> >

On Fri, Jan 23, 2026 at 07:29:52AM +0800, Guodong Xu wrote:
> On Fri, Jan 23, 2026 at 2:52 AM Conor Dooley <conor@kernel.org> wrote:
> >
> > 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@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?
> 
> I'm not sure. Would U-mode DTBs typically omit the privileged extensions like
> Smnpm/Ssnpm, making such a dependency impractical?

I don't actually know of any u-mode software that uses a devicetree, but
my guy feeling is that people won't trim out the lower-priv mode things
because they might want/need to know if those features are available on the
platform.

> > > +            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
> > >