On Mon, 16 Nov 2020 18:13:56 +0000, Sudeep Holla wrote:
> The CLKSCREW attack [0] exposed security vulnerabilities in energy management
> implementations where untrusted software had direct access to clock and
> voltage hardware controls. In this attack, the malicious software was able to
> place the platform into unsafe overclocked or undervolted configurations. Such
> configurations then enabled the injection of predictable faults to reveal
> secrets.
>
> Many Arm-based systems used to or still use voltage regulator and clock
> frameworks in the kernel. These frameworks allow callers to independently
> manipulate frequency and voltage settings. Such implementations can render
> systems susceptible to this form of attack.
>
> Attacks such as CLKSCREW are now being mitigated by not having direct and
> independent control of clock and voltage in the kernel and moving that
> control to a trusted entity, such as the SCP firmware or secure world
> firmware/software which are to perform sanity checking on the requested
> performance levels, thereby preventing any attempted malicious programming.
>
> With the advent of such an abstraction, there is a need to replace the
> generic clock and regulator bindings used by such devices with a generic
> performance domains bindings.
>
> [0]
> https://www.usenix.org/conference/usenixsecurity17/technical-sessions/presentation/tang
>
> Cc: Rob Herring <robh...@kernel.org>
> Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com>
> ---
> .../bindings/dvfs/performance-domain.yaml | 76 +++++++++++++++++++
> 1 file changed, 76 insertions(+)
> create mode 100644
> Documentation/devicetree/bindings/dvfs/performance-domain.yaml
>
> v1[1]->v2:
> - Changed to Dual License
> - Added select: true, enum for #performance-domain-cells and
> $ref for performance-domain
> - Changed the example to use real existing compatibles instead
> of made-up ones
>
> [1] https://lore.kernel.org/lkml/20201105173539.1426301-1-sudeep.ho...@arm.com
>
My bot found errors running 'make dt_binding_check' on your patch:
yamllint warnings/errors:
dtschema/dtc warnings/errors:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/ata/pata-common.example.dt.yaml:
/: '#performance-domain-cells' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/ata/sata-common.example.dt.yaml:
/: '#performance-domain-cells' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/ata/allwinner,sun8i-r40-ahci.example.dt.yaml:
/: '#performance-domain-cells' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/ata/allwinner,sun8i-r40-ahci.example.dt.yaml:
example-0: '#performance-domain-cells' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/ata/allwinner,sun8i-r40-ahci.example.dt.yaml:
sata@1c18000: '#performance-domain-cells' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/ata/imx-sata.example.dt.yaml:
/: '#performance-domain-cells' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.yaml
and on and on...
