Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 11 Oct 2021 08:08:44 +0200 | Subject | Re: [PATCH] iommu: fix ARM_SMMU vs QCOM_SCM compilation |
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On Mon, Oct 11, 2021 at 6:11 AM Dmitry Baryshkov <dmitry.baryshkov@linaro.org> wrote: > On Sun, 10 Oct 2021 at 20:42, Arnd Bergmann <arnd@arndb.de> wrote: > > The patch seems correct, but it becomes overcomplicated. What about: > - restoring QCOM_SCM stubs
The stubs are what has led to the previous bugs in this area to often go unnoticed for too long, as illustrated by your suggestion
> - making ARM_SMMU select QCOM_SCM if ARM_SMMU_QCOM
I assume you meant "select QCOM_SCM if ARCH_QCOM", after we stop using ARM_SMMU_QCOM?
> This would have almost the same result as with your patch, but without > extra ARM_SMMU_QCOM Kconfig symbol.
The "almost" is the problem: consider the case of
CONFIG_ARM=y CONFIG_COMPILE_TEST=y CONFIG_ARCH_QCOM=n CONFIG_ARM_SMMU=y CONFIG_DRM_MSM=m CONFIG_QCOM_SCM=m (selected by DRM_MSM)
The stubs here lead to ARM_SMMU linking against the QCOM_SCM driver from built-in code, which fails because QCOM_SCM itself is a loadable module.
We can move the "select QCOM_SCM" in the ARM_SMMU_QCOM symbol if we make that a tristate though, if you want to separate it a little more.
Arnd
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