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 <[email protected]>
---
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) {
+ 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;
+ }
}
root_cfg->smmu = smmu;
--
1.7.9.5
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