The sdm845 platform now supports TBUs, so let's get additional debug info from the TBUs when a context fault occurs. Implement a custom context fault handler that does both software + hardware page table walks and TLB Invalidate All. Signed-off-by: Georgi Djakov <quic_c_gdjako@xxxxxxxxxxx> --- .../iommu/arm/arm-smmu/arm-smmu-qcom-debug.c | 143 ++++++++++++++++++ drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 4 + 2 files changed, 147 insertions(+) diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom-debug.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom-debug.c index eff7ca94ec8d..552199cbd9e2 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom-debug.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom-debug.c @@ -345,6 +345,149 @@ static phys_addr_t qcom_iova_to_phys(struct arm_smmu_domain *smmu_domain, return phys; } +static phys_addr_t qcom_smmu_iova_to_phys_hard(struct arm_smmu_domain *smmu_domain, dma_addr_t iova) +{ + struct arm_smmu_device *smmu = smmu_domain->smmu; + int idx = smmu_domain->cfg.cbndx; + u32 frsynra; + u16 sid; + + frsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(idx)); + sid = FIELD_GET(ARM_SMMU_CBFRSYNRA_SID, frsynra); + + return qcom_iova_to_phys(smmu_domain, iova, sid); +} + +static phys_addr_t qcom_smmu_verify_fault(struct arm_smmu_domain *smmu_domain, dma_addr_t iova, u32 fsr) +{ + struct io_pgtable *iop = io_pgtable_ops_to_pgtable(smmu_domain->pgtbl_ops); + struct arm_smmu_device *smmu = smmu_domain->smmu; + phys_addr_t phys_post_tlbiall; + phys_addr_t phys; + + phys = qcom_smmu_iova_to_phys_hard(smmu_domain, iova); + io_pgtable_tlb_flush_all(iop); + phys_post_tlbiall = qcom_smmu_iova_to_phys_hard(smmu_domain, iova); + + if (phys != phys_post_tlbiall) { + dev_err(smmu->dev, + "ATOS results differed across TLBIALL... (before: %pa after: %pa)\n", + &phys, &phys_post_tlbiall); + } + + return (phys == 0 ? phys_post_tlbiall : phys); +} + +irqreturn_t qcom_smmu_context_fault(int irq, void *dev) +{ + struct arm_smmu_domain *smmu_domain = dev; + struct io_pgtable_ops *ops = smmu_domain->pgtbl_ops; + struct arm_smmu_device *smmu = smmu_domain->smmu; + u32 fsr, fsynr, cbfrsynra, resume = 0; + int idx = smmu_domain->cfg.cbndx; + phys_addr_t phys_soft; + unsigned long iova; + int ret, tmp; + + static DEFINE_RATELIMIT_STATE(_rs, + DEFAULT_RATELIMIT_INTERVAL, + DEFAULT_RATELIMIT_BURST); + + fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR); + if (!(fsr & ARM_SMMU_FSR_FAULT)) + return IRQ_NONE; + + fsynr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSYNR0); + iova = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_FAR); + cbfrsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(idx)); + + if (list_empty(&tbu_list)) { + ret = report_iommu_fault(&smmu_domain->domain, NULL, 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); + return IRQ_HANDLED; + } + + phys_soft = ops->iova_to_phys(ops, iova); + + tmp = report_iommu_fault(&smmu_domain->domain, NULL, iova, + fsynr & ARM_SMMU_FSYNR0_WNR ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ); + if (!tmp || tmp == -EBUSY) { + dev_dbg(smmu->dev, + "Context fault handled by client: iova=0x%08lx, fsr=0x%x, fsynr=0x%x, cb=%d\n", + iova, fsr, fsynr, idx); + dev_dbg(smmu->dev, "soft iova-to-phys=%pa\n", &phys_soft); + ret = IRQ_HANDLED; + resume = ARM_SMMU_RESUME_TERMINATE; + } else { + phys_addr_t phys_atos = qcom_smmu_verify_fault(smmu_domain, iova, fsr); + + if (__ratelimit(&_rs)) { + dev_err(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); + dev_err(smmu->dev, + "FSR = %08x [%s%s%s%s%s%s%s%s%s], SID=0x%x\n", + fsr, + (fsr & 0x02) ? "TF " : "", + (fsr & 0x04) ? "AFF " : "", + (fsr & 0x08) ? "PF " : "", + (fsr & 0x10) ? "EF " : "", + (fsr & 0x20) ? "TLBMCF " : "", + (fsr & 0x40) ? "TLBLKF " : "", + (fsr & 0x80) ? "MHF " : "", + (fsr & 0x40000000) ? "SS " : "", + (fsr & 0x80000000) ? "MULTI " : "", + cbfrsynra); + + dev_err(smmu->dev, + "soft iova-to-phys=%pa\n", &phys_soft); + if (!phys_soft) + dev_err(smmu->dev, + "SOFTWARE TABLE WALK FAILED! Looks like %s accessed an unmapped address!\n", + dev_name(smmu->dev)); + if (phys_atos) + dev_err(smmu->dev, "hard iova-to-phys (ATOS)=%pa\n", + &phys_atos); + else + dev_err(smmu->dev, "hard iova-to-phys (ATOS) failed\n"); + } + ret = IRQ_NONE; + resume = ARM_SMMU_RESUME_TERMINATE; + } + + /* + * If the client returns -EBUSY, do not clear FSR and do not RESUME + * if stalled. This is required to keep the IOMMU client stalled on + * the outstanding fault. This gives the client a chance to take any + * debug action and then terminate the stalled transaction. + * So, the sequence in case of stall on fault should be: + * 1) Do not clear FSR or write to RESUME here + * 2) Client takes any debug action + * 3) Client terminates the stalled transaction and resumes the IOMMU + * 4) Client clears FSR. The FSR should only be cleared after 3) and + * not before so that the fault remains outstanding. This ensures + * SCTLR.HUPCF has the desired effect if subsequent transactions also + * need to be terminated. + */ + if (tmp != -EBUSY) { + /* Clear the faulting FSR */ + arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, fsr); + + /* Retry or terminate any stalled transactions */ + if (fsr & ARM_SMMU_FSR_SS) + arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_RESUME, resume); + } + + return ret; +} + static int qcom_tbu_probe(struct platform_device *pdev) { struct of_phandle_args args = { .args_count = 2 }; diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c index 5c7cfc51b57c..a901230dbabd 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c @@ -422,6 +422,10 @@ static const struct arm_smmu_impl sdm845_smmu_500_impl = { .reset = qcom_sdm845_smmu500_reset, .write_s2cr = qcom_smmu_write_s2cr, .tlb_sync = qcom_smmu_tlb_sync, +#ifdef CONFIG_ARM_SMMU_QCOM_DEBUG + .context_fault = qcom_smmu_context_fault, + .context_fault_needs_threaded_irq = true, +#endif }; static const struct arm_smmu_impl qcom_adreno_smmu_v2_impl = {