[PATCH v5 1/5] iommu/arm-smmu: Save additional information on context fault

[Connor Abbott]

On Tue, May 6, 2025 at 7:32 AM Will Deacon <will at kernel.org> wrote:
>
> On Wed, Mar 19, 2025 at 10:44:00AM -0400, Connor Abbott wrote:
> > This will be used by drm/msm for GPU page faults, replacing the manual
> > register reading it does.
> >
> > Signed-off-by: Connor Abbott <cwabbott0 at gmail.com>
> > Reviewed-by: Rob Clark <robdclark at gmail.com>
> > ---
> >  drivers/iommu/arm/arm-smmu/arm-smmu-qcom-debug.c |  6 ++--
> >  drivers/iommu/arm/arm-smmu/arm-smmu.c            | 35 ++++++++++++++----------
> >  drivers/iommu/arm/arm-smmu/arm-smmu.h            |  7 +++--
> >  3 files changed, 29 insertions(+), 19 deletions(-)
>
> [...]
>
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > index ade4684c14c9b2724a71e2457288dbfaf7562c83..a02078eb968b81a35c1c086ed7007ea2a453ef94 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> > @@ -405,13 +405,20 @@ static const struct iommu_flush_ops arm_smmu_s2_tlb_ops_v1 = {
> >  };
> >
> >
> > -void arm_smmu_read_context_fault_info(struct arm_smmu_device *smmu, int idx,
> > +void arm_smmu_read_context_fault_info(struct arm_smmu_domain *smmu_domain,
> >                                     struct arm_smmu_context_fault_info *cfi)
> >  {
> > +     struct arm_smmu_device *smmu = smmu_domain->smmu;
> > +     int idx = smmu_domain->cfg.cbndx;
> > +
> >       cfi->iova = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_FAR);
> > +     cfi->ttbr0 = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_TTBR0);
> >       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->fsynr0 = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSYNR0);
> > +     cfi->fsynr1 = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_FSYNR1);
> >       cfi->cbfrsynra = arm_smmu_gr1_read(smmu, ARM_SMMU_GR1_CBFRSYNRA(idx));
> > +     if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1)
> > +             cfi->contextidr = arm_smmu_cb_read(smmu, idx, ARM_SMMU_CB_CONTEXTIDR);
>
> I think this leaves 'cfi->contextidr' uninitialised for stage-2 domains.
> We should probably either zero it here or just zero-initialise the whole
> 'cfi' struct in arm_smmu_context_fault() with a:
>
>         struct arm_smmu_context_fault_info cfi = {};
>
> line.
>
> Will

The next patch moves the context fault info into arm_smmu_domain which
is already zero-initialized.

Connor