On Tue, Nov 24, 2020 at 12:15:58PM -0700, Jordan Crouse wrote: > Call report_iommu_fault() to allow upper-level drivers to register their > own fault handlers. > > Signed-off-by: Jordan Crouse <jcro...@codeaurora.org> > --- > > drivers/iommu/arm/arm-smmu/arm-smmu.c | 16 +++++++++++++--- > 1 file changed, 13 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c > b/drivers/iommu/arm/arm-smmu/arm-smmu.c > index 0f28a8614da3..7fd18bbda8f5 100644 > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c > @@ -427,6 +427,7 @@ static irqreturn_t arm_smmu_context_fault(int irq, void > *dev) > struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); > struct arm_smmu_device *smmu = smmu_domain->smmu; > int idx = smmu_domain->cfg.cbndx; > + int ret; > > fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR); > if (!(fsr & ARM_SMMU_FSR_FAULT)) > @@ -436,11 +437,20 @@ static irqreturn_t arm_smmu_context_fault(int irq, void > *dev) > iova = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_FAR); > cbfrsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(idx)); > > - dev_err_ratelimited(smmu->dev, > - "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, > cbfrsynra=0x%x, cb=%d\n", > + ret = report_iommu_fault(domain, dev, iova, > + fsynr & ARM_SMMU_FSYNR0_WNR ? IOMMU_FAULT_WRITE : > IOMMU_FAULT_READ); > + > + if (ret == -ENOSYS) > + dev_err_ratelimited(smmu->dev, > + "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, > cbfrsynra=0x%x, cb=%d\n", > fsr, iova, fsynr, cbfrsynra, idx); > > - arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, fsr); > + /* > + * If the iommu fault returns an error (except -ENOSYS) then assume that > + * they will handle resuming on their own > + */ > + if (!ret || ret == -ENOSYS) > + arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, fsr);
Hmm, I don't grok this part. If the fault handler returned an error and we don't clear the FSR, won't we just re-take the irq immediately? I think it would be better to do this unconditionally, and print the "Unhandled context fault" message for any non-zero value of ret. Will
