RE: [PATCH net-next] net: enetc: use get/put_unaligned() for mac address handling

-----Original Message-----
From: Heiner Kallweit <hkallweit1@gmail.com>
Sent: Friday, June 4, 2021 3:44 PM

[...]

On 04.06.2021 14:30, Michael Walle wrote:

quoted

The supplied buffer for the MAC address might not be aligned. Thus
doing a 32bit (or 16bit) access could be on an unaligned address. For
now, enetc is only used on aarch64 which can do unaligned accesses, thus
there is no error. In any case, be correct and use the get/put_unaligned()
helpers.

Signed-off-by: Michael Walle <redacted>
---
 drivers/net/ethernet/freescale/enetc/enetc_pf.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc_pf.c

b/drivers/net/ethernet/freescale/enetc/enetc_pf.c

quoted

index 31274325159a..a96d2acb5e11 100644

--- a/drivers/net/ethernet/freescale/enetc/enetc_pf.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc_pf.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
 /* Copyright 2017-2019 NXP */

+#include <asm/unaligned.h>
 #include <linux/mdio.h>
 #include <linux/module.h>
 #include <linux/fsl/enetc_mdio.h>

@@ -17,15 +18,15 @@ static void enetc_pf_get_primary_mac_addr(struct

enetc_hw *hw, int si, u8 *addr)

quoted

 	u32 upper = __raw_readl(hw->port + ENETC_PSIPMAR0(si));
 	u16 lower = __raw_readw(hw->port + ENETC_PSIPMAR1(si));

-	*(u32 *)addr = upper;
-	*(u16 *)(addr + 4) = lower;
+	put_unaligned(upper, (u32 *)addr);
+	put_unaligned(lower, (u16 *)(addr + 4));

I think you want to write little endian, therefore on a BE platform
this code may be wrong. Better use put_unaligned_le32?
By using these versions of the unaligned helpers you could also
remove the pointer cast.

+1