Patch "of/irq: Fix msi-map calculation for nonzero rid-base" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

of/irq: Fix msi-map calculation for nonzero rid-base

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
of-irq-fix-msi-map-calculation-for-nonzero-rid-base.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Robin Murphy <[email protected]>
Date: Tue, 9 Feb 2016 11:04:45 +0000
Subject: of/irq: Fix msi-map calculation for nonzero rid-base

From: Robin Murphy <[email protected]>

commit 5d589d81acf974d23af98044aac56c6339d659f8 upstream.

The existing msi-map code is fine for shifting the entire RID space upwards, but attempting finer-grained remapping reveals a bug. It turns out that we are mistakenly treating the msi-base part as an offset, not as a new base to remap onto, so things get squiffy when rid-base is nonzero. Fix this, and at the same time add a sanity check against having msi-map-mask clash with a nonzero rid-base, as that's another thing one can easily get wrong.

---
 drivers/of/irq.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

@@ -636,6 +636,13 @@ static u32 __of_msi_map_rid(struct devic
 		msi_base = be32_to_cpup(msi_map + 2);
 		rid_len = be32_to_cpup(msi_map + 3);
 
+		if (rid_base & ~map_mask) {
+			dev_err(parent_dev,
+				"Invalid msi-map translation - msi-map-mask (0x%x) ignores rid-base (0x%x)\n",
+				map_mask, rid_base);
+			return rid_out;
+		}
+
 		msi_controller_node = of_find_node_by_phandle(phandle);
 
 		matched = (masked_rid >= rid_base &&

@@ -655,7 +662,7 @@ static u32 __of_msi_map_rid(struct devic
 	if (!matched)
 		return rid_out;
 
-	rid_out = masked_rid + msi_base;
+	rid_out = masked_rid - rid_base + msi_base;
 	dev_dbg(dev,
 		"msi-map at: %s, using mask %08x, rid-base: %08x, msi-base: %08x, length: %08x, rid: %08x -> %08x\n",
 		dev_name(parent_dev), map_mask, rid_base, msi_base,

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/of-irq-fix-msi-map-calculation-for-nonzero-rid-base.patch