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Subject[PATCH] of/irq: Fix msi-map calculation for nonzero rid-base
Date
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.

CC: <stable@vger.kernel.org>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/of/irq.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 7ee21ae..e7bfc17 100644
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -635,6 +635,13 @@ static u32 __of_msi_map_rid(struct device *dev, struct device_node **np,
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 &&
@@ -654,7 +661,7 @@ static u32 __of_msi_map_rid(struct device *dev, struct device_node **np,
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,
--
2.7.0.25.gfc10eb5.dirty
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