Re: [PATCH v3 3/3] iommu/arm-smmu: Pretty-print context fault related regs

Pranjal Shrivastava
2024-08-22T10:31:57Z

On Thu, Aug 22, 2024 at 03:39:41PM +0530, Manivannan Sadhasivam wrote:
> On Mon, Jul 01, 2024 at 09:20:12AM -0700, Rob Clark wrote:
> > From: Rob Clark <robdclark@chromium.org>
> >
> > Parse out the bitfields for easier-to-read fault messages.
> >
> > Signed-off-by: Rob Clark <robdclark@chromium.org>
> > ---
> > .../iommu/arm/arm-smmu/arm-smmu-qcom-debug.c | 52 +++++---------
> > drivers/iommu/arm/arm-smmu/arm-smmu.c | 70 +++++++++++++++----
> > drivers/iommu/arm/arm-smmu/arm-smmu.h | 21 ++++++
> > 3 files changed, 92 insertions(+), 51 deletions(-)
> >
>
> [...]
>
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > index 23cf91ac409b..79ec911ae151 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > @@ -405,32 +405,72 @@ static const struct iommu_flush_ops arm_smmu_s2_tlb_ops_v1 = {
> > .tlb_add_page = arm_smmu_tlb_add_page_s2_v1,
> > };
> >
> > +
> > +void arm_smmu_read_context_fault_info(struct arm_smmu_device *smmu, int idx,
> > + struct arm_smmu_context_fault_info *cfi)
> > +{
> > + cfi->iova = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_FAR);
> > + cfi->fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR);
> > + cfi->fsynr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSYNR0);
> > + cfi->cbfrsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(idx));
> > +}
> > +
> > +void arm_smmu_print_context_fault_info(struct arm_smmu_device *smmu, int idx,
> > + const struct arm_smmu_context_fault_info *cfi)
> > +{
> > + dev_dbg(smmu->dev,
> > + "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra=0x%x, cb=%d\n",
> > + cfi->fsr, cfi->iova, cfi->fsynr, cfi->cbfrsynra, idx);
> > +
>
> I just happen to hit an IOMMU fault in 6.11-rc4 and I did not see the 'Unhandled
> context fault' log, but just the register dump in dmesg. Tracking that lead me
> to this patch.
>
> May I know the reasoning behind making the actual error message _dbg()? It is
> intentional first place?
>
> - Mani

Hi Mani,

That was a miss in this series, but it was fixed recently in [1].
I think it should land soon.

[1] https://lore.kernel.org/linux-iommu/172381862229.1794487.17068761066364130246.b4-ty@kernel.org/

Thanks,
Pranjal

>
> > + dev_err(smmu->dev, "FSR = %08x [%s%sFormat=%u%s%s%s%s%s%s%s%s], SID=0x%x\n",
> > + cfi->fsr,
> > + (cfi->fsr & ARM_SMMU_CB_FSR_MULTI) ? "MULTI " : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_SS) ? "SS " : "",
> > + (u32)FIELD_GET(ARM_SMMU_CB_FSR_FORMAT, cfi->fsr),
> > + (cfi->fsr & ARM_SMMU_CB_FSR_UUT) ? " UUT" : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_ASF) ? " ASF" : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_TLBLKF) ? " TLBLKF" : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_TLBMCF) ? " TLBMCF" : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_EF) ? " EF" : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_PF) ? " PF" : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_AFF) ? " AFF" : "",
> > + (cfi->fsr & ARM_SMMU_CB_FSR_TF) ? " TF" : "",
> > + cfi->cbfrsynra);
> > +
> > + dev_err(smmu->dev, "FSYNR0 = %08x [S1CBNDX=%u%s%s%s%s%s%s PLVL=%u]\n",
> > + cfi->fsynr,
> > + (u32)FIELD_GET(ARM_SMMU_CB_FSYNR0_S1CBNDX, cfi->fsynr),
> > + (cfi->fsynr & ARM_SMMU_CB_FSYNR0_AFR) ? " AFR" : "",
> > + (cfi->fsynr & ARM_SMMU_CB_FSYNR0_PTWF) ? " PTWF" : "",
> > + (cfi->fsynr & ARM_SMMU_CB_FSYNR0_NSATTR) ? " NSATTR" : "",
> > + (cfi->fsynr & ARM_SMMU_CB_FSYNR0_IND) ? " IND" : "",
> > + (cfi->fsynr & ARM_SMMU_CB_FSYNR0_PNU) ? " PNU" : "",
> > + (cfi->fsynr & ARM_SMMU_CB_FSYNR0_WNR) ? " WNR" : "",
> > + (u32)FIELD_GET(ARM_SMMU_CB_FSYNR0_PLVL, cfi->fsynr));
> > +}
> > +
> > static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
> > {
> > - u32 fsr, fsynr, cbfrsynra;
> > - unsigned long iova;
> > + struct arm_smmu_context_fault_info cfi;
> > struct arm_smmu_domain *smmu_domain = dev;
> > struct arm_smmu_device *smmu = smmu_domain->smmu;
> > + static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
> > + DEFAULT_RATELIMIT_BURST);
> > int idx = smmu_domain->cfg.cbndx;
> > int ret;
> >
> > - fsr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSR);
> > - if (!(fsr & ARM_SMMU_CB_FSR_FAULT))
> > - return IRQ_NONE;
> > + arm_smmu_read_context_fault_info(smmu, idx, &cfi);
> >
> > - 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 (!(cfi.fsr & ARM_SMMU_CB_FSR_FAULT))
> > + return IRQ_NONE;
> >
> > - ret = report_iommu_fault(&smmu_domain->domain, NULL, iova,
> > - fsynr & ARM_SMMU_CB_FSYNR0_WNR ? IOMMU_FAULT_WRITE : IOMMU_FAULT_READ);
> > + ret = report_iommu_fault(&smmu_domain->domain, NULL, cfi.iova,
> > + cfi.fsynr & ARM_SMMU_CB_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);
> > + if (ret == -ENOSYS && __ratelimit(&rs))
> > + arm_smmu_print_context_fault_info(smmu, idx, &cfi);
> >
> > - arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, fsr);
> > + arm_smmu_cb_write(smmu, idx, ARM_SMMU_CB_FSR, cfi.fsr);
> > return IRQ_HANDLED;
> > }
> >
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > index b04a00126a12..e2aeb511ae90 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
> > @@ -198,6 +198,7 @@ enum arm_smmu_cbar_type {
> > #define ARM_SMMU_CB_FSR 0x58
> > #define ARM_SMMU_CB_FSR_MULTI BIT(31)
> > #define ARM_SMMU_CB_FSR_SS BIT(30)
> > +#define ARM_SMMU_CB_FSR_FORMAT GENMASK(10, 9)
> > #define ARM_SMMU_CB_FSR_UUT BIT(8)
> > #define ARM_SMMU_CB_FSR_ASF BIT(7)
> > #define ARM_SMMU_CB_FSR_TLBLKF BIT(6)
> > @@ -223,7 +224,14 @@ enum arm_smmu_cbar_type {
> > #define ARM_SMMU_CB_FAR 0x60
> >
> > #define ARM_SMMU_CB_FSYNR0 0x68
> > +#define ARM_SMMU_CB_FSYNR0_PLVL GENMASK(1, 0)
> > #define ARM_SMMU_CB_FSYNR0_WNR BIT(4)
> > +#define ARM_SMMU_CB_FSYNR0_PNU BIT(5)
> > +#define ARM_SMMU_CB_FSYNR0_IND BIT(6)
> > +#define ARM_SMMU_CB_FSYNR0_NSATTR BIT(8)
> > +#define ARM_SMMU_CB_FSYNR0_PTWF BIT(10)
> > +#define ARM_SMMU_CB_FSYNR0_AFR BIT(11)
> > +#define ARM_SMMU_CB_FSYNR0_S1CBNDX GENMASK(23, 16)
> >
> > #define ARM_SMMU_CB_FSYNR1 0x6c
> >
> > @@ -533,4 +541,17 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu);
> > void arm_smmu_write_context_bank(struct arm_smmu_device *smmu, int idx);
> > int arm_mmu500_reset(struct arm_smmu_device *smmu);
> >
> > +struct arm_smmu_context_fault_info {
> > + unsigned long iova;
> > + u32 fsr;
> > + u32 fsynr;
> > + u32 cbfrsynra;
> > +};
> > +
> > +void arm_smmu_read_context_fault_info(struct arm_smmu_device *smmu, int idx,
> > + struct arm_smmu_context_fault_info *cfi);
> > +
> > +void arm_smmu_print_context_fault_info(struct arm_smmu_device *smmu, int idx,
> > + const struct arm_smmu_context_fault_info *cfi);
> > +
> > #endif /* _ARM_SMMU_H */
> > --
> > 2.45.2
> >
> >
>
> --
> மணிவண்ணன் சதாசிவம்