On Fri, 2019-09-13 at 12:48 +0100, Robin Murphy wrote: > Although CONFIG_ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT is a welcome tool > for smoking out inadequate firmware, the failure mode is non-obvious > and can be confusing for end users. Add some special-case reporting of > Unidentified Stream Faults to help clarify this particular symptom. > > CC: Douglas Anderson <[email protected]> > Signed-off-by: Robin Murphy <[email protected]> > --- > drivers/iommu/arm-smmu.c | 5 +++++ > drivers/iommu/arm-smmu.h | 2 ++ > 2 files changed, 7 insertions(+) > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index b7cf24402a94..76ac8c180695 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -499,6 +499,11 @@ static irqreturn_t arm_smmu_global_fault(int irq, void > *dev) > dev_err_ratelimited(smmu->dev, > "\tGFSR 0x%08x, GFSYNR0 0x%08x, GFSYNR1 0x%08x, GFSYNR2 > 0x%08x\n", > gfsr, gfsynr0, gfsynr1, gfsynr2); > + if (IS_ENABLED(CONFIG_ARM_SMMU_DISABLE_BYPASS_BY_DEFAULT) && > + (gfsr & sGFSR_USF)) > + dev_err_ratelimited(smmu->dev, > + "Stream ID %hu may not be described by firmware, try > booting with \"arm-smmu.disable_bypass=0\"\n", > + (u16)gfsynr1);
dev_err_once(), i.e., don't need to remind people to set "arm- smmu.disable_bypass=0" multiple times. > > arm_smmu_gr0_write(smmu, ARM_SMMU_GR0_sGFSR, gfsr); > return IRQ_HANDLED; > diff --git a/drivers/iommu/arm-smmu.h b/drivers/iommu/arm-smmu.h > index c9c13b5785f2..46f7e161e83e 100644 > --- a/drivers/iommu/arm-smmu.h > +++ b/drivers/iommu/arm-smmu.h > @@ -79,6 +79,8 @@ > #define ID7_MINOR GENMASK(3, 0) > > #define ARM_SMMU_GR0_sGFSR 0x48 > +#define sGFSR_USF BIT(2) > + > #define ARM_SMMU_GR0_sGFSYNR0 0x50 > #define ARM_SMMU_GR0_sGFSYNR1 0x54 > #define ARM_SMMU_GR0_sGFSYNR2 0x58 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
