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+dt@xxxxxxxxxx> > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx> > --- > .../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.holla@xxxxxxx > 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...
