On Wed, 07 Apr 2021 14:59:13 +0100, 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
>
> Link: https://lore.kernel.org/r/20201116181356.804590-1-sudeep.ho...@arm.com
> Cc: Rob Herring <robh...@kernel.org>
> Acked-by: Viresh Kumar <viresh.ku...@linaro.org>
> Signed-off-by: Sudeep Holla <sudeep.ho...@arm.com>
> ---
>
> Hi All,
>
> Sorry for the delay, I thought I had sent this out last week and it turns
> out that I had dry-run in my git email command and never removed it. Just
> noticed now looking for response for this patch on the list to find out
> that I never sent it out :(.
>
> v2[2]->v3:
> - Dropped required properties
> - Added non cpu device example
> - Updated cpu bindings too
>
> v1[1]->v2[2]:
> - 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
> [2] https://lore.kernel.org/lkml/20201116181356.804590-1-sudeep.ho...@arm.com
>
> .../devicetree/bindings/arm/cpus.yaml | 7 ++
> .../bindings/dvfs/performance-domain.yaml | 80 +++++++++++++++++++
> 2 files changed, 87 insertions(+)
> create mode 100644
> Documentation/devicetree/bindings/dvfs/performance-domain.yaml
>
My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):
yamllint warnings/errors:
dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/dvfs/performance-domain.example.dt.yaml:0:0:
/example-0/performance-controller@12340000: failed to match any schema with
compatible: ['qcom,cpufreq-hw']
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.example.dt.yaml:
gpu@2d000000: compatible: 'oneOf' conditional failed, one must be fixed:
['arm,mali-t624'] is too short
'arm,mali-t624' is not one of ['samsung,exynos5250-mali']
'arm,mali-t624' is not one of ['samsung,exynos5420-mali']
'arm,mali-t624' is not one of ['allwinner,sun50i-h6-mali']
'arm,mali-t624' is not one of ['amlogic,meson-gxm-mali',
'realtek,rtd1295-mali']
'arm,mali-t624' is not one of ['arm,juno-mali']
'arm,mali-t624' is not one of ['rockchip,rk3288-mali',
'samsung,exynos5433-mali']
'arm,mali-t624' is not one of ['rockchip,rk3399-mali']
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.example.dt.yaml:
gpu@2d000000: 'interrupt-names' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.example.dt.yaml:
gpu@2d000000: 'clocks' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.example.dt.yaml:
gpu@2d000000: 'performance-domains' does not match any of the regexes:
'pinctrl-[0-9]+'
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/dvfs/performance-domain.example.dt.yaml:
gpu@2d000000: 'oneOf' conditional failed, one must be fixed:
'interrupts' is a required property
'interrupts-extended' is a required property
From schema:
/builds/robherring/linux-dt-review/Documentation/devicetree/bindings/gpu/arm,mali-midgard.yaml
See https://patchwork.ozlabs.org/patch/1463354
This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.
If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:
pip3 install dtschema --upgrade
Please check and re-submit.
