RE: [PATCH] iommu/arm-smmu: fix the module name for disable_bypass parameter
From: Leo Li
Date: Tue Feb 11 2020 - 18:56:15 EST
> -----Original Message-----
> From: Russell King - ARM Linux admin <linux@xxxxxxxxxxxxxxx>
> Sent: Tuesday, February 11, 2020 5:46 PM
> To: Leo Li <leoyang.li@xxxxxxx>
> Cc: Joerg Roedel <joro@xxxxxxxxxx>; Will Deacon <will.deacon@xxxxxxx>;
> Robin Murphy <robin.murphy@xxxxxxx>; iommu@xxxxxxxxxxxx
> foundation.org; linux-kernel@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH] iommu/arm-smmu: fix the module name for
> disable_bypass parameter
>
> On Tue, Feb 11, 2020 at 05:36:55PM -0600, Li Yang wrote:
> > Since commit cd221bd24ff5 ("iommu/arm-smmu: Allow building as a
> > module"), there is a side effect that the module name is changed from
> > arm-smmu to arm-smmu-mod. So the kernel parameter for
> disable_bypass
> > need to be changed too. Fix the Kconfig help and error message to the
> > correct parameter name.
>
> Hmm, this seems to be a user-visible change - so those of us who have been
> booting with "arm-smmu.disable_bypass=0" now need to change that
> depending on which kernel is being booted - which is not nice, and makes
> the support side on platforms that need this kernel parameter harder.
I agree. Probably a better fix is to update the Makefile to change the module name back to the original one.
Regards,
Leo
>
> >
> > Signed-off-by: Li Yang <leoyang.li@xxxxxxx>
> > ---
> > drivers/iommu/Kconfig | 2 +-
> > drivers/iommu/arm-smmu.c | 2 +-
> > 2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index
> > d2fade984999..fb54be903c60 100644
> > --- a/drivers/iommu/Kconfig
> > +++ b/drivers/iommu/Kconfig
> > @@ -415,7 +415,7 @@ config
> ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT
> > hardcode the bypass disable in the code.
> >
> > NOTE: the kernel command line parameter
> > - 'arm-smmu.disable_bypass' will continue to override this
> > + 'arm-smmu-mod.disable_bypass' will continue to override this
> > config.
> >
> > config ARM_SMMU_V3
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index
> > 16c4b87af42b..2ffe8ff04393 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -512,7 +512,7 @@ static irqreturn_t arm_smmu_global_fault(int irq,
> void *dev)
> > if
> (IS_ENABLED(CONFIG_ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT) &&
> > (gfsr & ARM_SMMU_sGFSR_USF))
> > dev_err(smmu->dev,
> > - "Blocked unknown Stream ID 0x%hx; boot
> with \"arm-smmu.disable_bypass=0\" to allow, but this may have security
> implications\n",
> > + "Blocked unknown Stream ID 0x%hx; boot
> with
> > +\"arm-smmu-mod.disable_bypass=0\" to allow, but this may have
> > +security implications\n",
> > (u16)gfsynr1);
> > else
> > dev_err(smmu->dev,
> > --
> > 2.17.1
> >
> >
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