[PATCH] omap: iommu: disallow mapping NULL address

[Michael Jones <michael.jones@matrix-vision.de>]

>From e7dbe4c4b64eb114f9b0804d6af3a3ca0e78acc8 Mon Sep 17 00:00:00 2001
From: Michael Jones <michael.jones@matrix-vision.de>
Date: Mon, 7 Mar 2011 13:36:15 +0100
Subject: [PATCH] omap: iommu: disallow mapping NULL address

commit c7f4ab26e3bcdaeb3e19ec658e3ad9092f1a6ceb allowed mapping
the NULL address if da_start==0.  Force da_start to exclude the
first page.

Signed-off-by: Michael Jones <michael.jones@matrix-vision.de>
---
 arch/arm/plat-omap/iommu.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/arm/plat-omap/iommu.c b/arch/arm/plat-omap/iommu.c
index 5990ea6..dcb5513 100644
--- a/arch/arm/plat-omap/iommu.c
+++ b/arch/arm/plat-omap/iommu.c
@@ -850,7 +850,7 @@ int iommu_set_da_range(struct iommu *obj, u32 start, u32 end)
 	if (end < start || !PAGE_ALIGN(start | end))
 		return -EINVAL;
 
-	obj->da_start = start;
+	obj->da_start = max(start, (u32)PAGE_SIZE);
 	obj->da_end = end;
 
 	return 0;
@@ -950,7 +950,9 @@ static int __devinit omap_iommu_probe(struct platform_device *pdev)
 	obj->name = pdata->name;
 	obj->dev = &pdev->dev;
 	obj->ctx = (void *)obj + sizeof(*obj);
-	obj->da_start = pdata->da_start;
+
+	/* reserve the first page for NULL */
+	obj->da_start = max(pdata->da_start, (u32)PAGE_SIZE);
 	obj->da_end = pdata->da_end;
 
 	mutex_init(&obj->iommu_lock);
-- 
1.7.4.1


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