On Tue, Sep 24, 2013 at 11:40:48AM -0400, Will Deacon wrote: > On Tue, Sep 24, 2013 at 04:06:58PM +0100, Andreas Herrmann wrote: > > With the right (or wrong;-) definition of v1 SMMU node in DTB it is > > possible to trigger a division by zero in arm_smmu_init_domain_context > > (if number of context irqs is 0): > > > > if (smmu->version == 1) { > > root_cfg->irptndx = atomic_inc_return(&smmu->irptndx); > > → root_cfg->irptndx %= smmu->num_context_irqs; > > } else { > > > > Avoid this by checking for num_context_irqs > 0 before trying to > > assign interrupts to contexts. > > > > Signed-off-by: Andreas Herrmann <andreas.herrm...@calxeda.com> > > --- > > drivers/iommu/arm-smmu.c | 31 +++++++++++++++++-------------- > > 1 file changed, 17 insertions(+), 14 deletions(-) > > > > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > > index f5a856e..0dfd255 100644 > > --- a/drivers/iommu/arm-smmu.c > > +++ b/drivers/iommu/arm-smmu.c > > @@ -828,21 +828,24 @@ static int arm_smmu_init_domain_context(struct > > iommu_domain *domain, > > return ret; > > > > root_cfg->cbndx = ret; > > - if (smmu->version == 1) { > > - root_cfg->irptndx = atomic_inc_return(&smmu->irptndx); > > - root_cfg->irptndx %= smmu->num_context_irqs; > > - } else { > > - root_cfg->irptndx = root_cfg->cbndx; > > - } > > > > - irq = smmu->irqs[smmu->num_global_irqs + root_cfg->irptndx]; > > - ret = request_irq(irq, arm_smmu_context_fault, IRQF_SHARED, > > - "arm-smmu-context-fault", domain); > > - if (IS_ERR_VALUE(ret)) { > > - dev_err(smmu->dev, "failed to request context IRQ %d (%u)\n", > > - root_cfg->irptndx, irq); > > - root_cfg->irptndx = -1; > > - goto out_free_context; > > + if (smmu->num_context_irqs) { > > Can we move this check to probe time, to avoid re-evaluating it every time > we initialise a new domain?
Yes, I'll move this check and issue an error message when there is not at least one context interrupt available. Andreas _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu