openwrt/target/linux/generic/backport-5.10/738-v5.14-01-net-dsa-qca8k-fix-an-endian-bug-in-qca8k-get-ethtool.patch

aFrom aa3d020b22cb844ab7bdbb9e5d861a64666e2b74 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <[email protected]>
Date: Wed, 9 Jun 2021 12:52:12 +0300
Subject: [PATCH] net: dsa: qca8k: fix an endian bug in
 qca8k_get_ethtool_stats()

The "hi" variable is a u64 but the qca8k_read() writes to the top 32
bits of it.  That will work on little endian systems but it's a bit
subtle.  It's cleaner to make declare "hi" as a u32.  We will still need
to cast it when we shift it later on in the function but that's fine.

Fixes: 7c9896e37807 ("net: dsa: qca8k: check return value of read functions correctly")
Signed-off-by: Dan Carpenter <[email protected]>
Reviewed-by: Vladimir Oltean <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
---
 drivers/net/dsa/qca8k.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -1412,7 +1412,7 @@ qca8k_get_ethtool_stats(struct dsa_switc
 	struct qca8k_priv *priv = (struct qca8k_priv *)ds->priv;
 	const struct qca8k_mib_desc *mib;
 	u32 reg, i, val;
-	u64 hi = 0;
+	u32 hi = 0;
 	int ret;
 
 	for (i = 0; i < ARRAY_SIZE(ar8327_mib); i++) {
@@ -1424,14 +1424,14 @@ qca8k_get_ethtool_stats(struct dsa_switc
 			continue;
 
 		if (mib->size == 2) {
-			ret = qca8k_read(priv, reg + 4, (u32 *)&hi);
+			ret = qca8k_read(priv, reg + 4, &hi);
 			if (ret < 0)
 				continue;
 		}
 
 		data[i] = val;
 		if (mib->size == 2)
-			data[i] |= hi << 32;
+			data[i] |= (u64)hi << 32;
 	}
 }