iommu/rockchip: prevent iommus dead loop when two masters share one IOMMU

commit 62e062a29ad5133f67c20b333ba0a952a99161ae upstream.

When two masters share an IOMMU, calling ops->of_xlate during
the second master's driver init may overwrite iommu->domain set
by the first. This causes the check if (iommu->domain == domain)
in rk_iommu_attach_device() to fail, resulting in the same
iommu->node being added twice to &rk_domain->iommus, which can
lead to an infinite loop in subsequent &rk_domain->iommus operations.

Cc: <stable@vger.kernel.org>
Fixes: 25c2325575cc ("iommu/rockchip: Add missing set_platform_dma_ops callback")
Signed-off-by: Simon Xue <xxm@rock-chips.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/20250623020018.584802-1-xxm@rock-chips.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 4b369419b32ce1b571f836e11f92452943a753c6..4c7f470a4752f2a739079c764490be9ad72e258a 100644 (file)
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -1154,7 +1154,6 @@ static int rk_iommu_of_xlate(struct device *dev,
        iommu_dev = of_find_device_by_node(args->np);
 
        data->iommu = platform_get_drvdata(iommu_dev);
-       data->iommu->domain = &rk_identity_domain;
        dev_iommu_priv_set(dev, data);
 
        platform_device_put(iommu_dev);
@@ -1192,6 +1191,8 @@ static int rk_iommu_probe(struct platform_device *pdev)
        if (!iommu)
                return -ENOMEM;
 
+       iommu->domain = &rk_identity_domain;
+
        platform_set_drvdata(pdev, iommu);
        iommu->dev = dev;
        iommu->num_mmu = 0;