iommu/arm-smmu: fix possible null-ptr-deref in arm_smmu_device_probe()

[ Upstream commit d9ed8af1dee37f181096631fb03729ece98ba816 ]

It will cause null-ptr-deref when using 'res', if platform_get_resource()
returns NULL, so move using 'res' after devm_ioremap_resource() that
will check it to avoid null-ptr-deref.
And use devm_platform_get_and_ioremap_resource() to simplify code.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Link: https://lore.kernel.org/r/20220425114136.2649310-1-yangyingliang@huawei.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index 4bc75c4..324e8f3 100644 (file)
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -2090,11 +2090,10 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
        if (err)
                return err;
 
-       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       ioaddr = res->start;
-       smmu->base = devm_ioremap_resource(dev, res);
+       smmu->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(smmu->base))
                return PTR_ERR(smmu->base);
+       ioaddr = res->start;
        /*
         * The resource size should effectively match the value of SMMU_TOP;
         * stash that temporarily until we know PAGESIZE to validate it with.