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net: ethernet: xscale: Check for PTP support properly

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In ixp4xx_get_ts_info() ixp46x_ptp_find() is called
unconditionally despite this feature only existing on
ixp46x, leading to the following splat from tcpdump:

root@OpenWrt:~# tcpdump -vv -X -i eth0
(...)
Unable to handle kernel NULL pointer dereference at virtual address
  00000238 when read
(...)
Call trace:
 ptp_clock_index from ixp46x_ptp_find+0x1c/0x38
 ixp46x_ptp_find from ixp4xx_get_ts_info+0x4c/0x64
 ixp4xx_get_ts_info from __ethtool_get_ts_info+0x90/0x108
 __ethtool_get_ts_info from __dev_ethtool+0xa00/0x2648
 __dev_ethtool from dev_ethtool+0x160/0x234
 dev_ethtool from dev_ioctl+0x2cc/0x460
 dev_ioctl from sock_ioctl+0x1ec/0x524
 sock_ioctl from sys_ioctl+0x51c/0xa94
 sys_ioctl from ret_fast_syscall+0x0/0x44
 (...)
Segmentation fault

Check for ixp46x in ixp46x_ptp_find() before trying to set up
PTP to avoid this.

To avoid altering the returned error code from ixp4xx_hwtstamp_set()
which before this patch was -EOPNOTSUPP, we return -EOPNOTSUPP
from ixp4xx_hwtstamp_set() if ixp46x_ptp_find() fails no matter
the error code. The helper function ixp46x_ptp_find() helper
returns -ENODEV.

Fixes: 9055a2f591 ("ixp4xx_eth: make ptp support a platform driver")
Signed-off-by: Linus Walleij <linusw@kernel.org>
Link: https://patch.msgid.link/20260219-ixp4xx-fix-ethernet-v3-1-f235ccc3cd46@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Linus Walleij
2026-02-19 12:38:50 +01:00
committed by Jakub Kicinski
parent 2bb995e615
commit 594163ea88
2 changed files with 4 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/net/ethernet/xscale/ixp4xx_eth.c
View File

@@ -403,15 +403,12 @@ static int ixp4xx_hwtstamp_set(struct net_device *netdev,
int ret;
int ch;
if (!cpu_is_ixp46x())
return -EOPNOTSUPP;
if (!netif_running(netdev))
return -EINVAL;
ret = ixp46x_ptp_find(&port->timesync_regs, &port->phc_index);
if (ret)
return ret;
return -EOPNOTSUPP;
ch = PORT2CHANNEL(port);
regs = port->timesync_regs;

3
drivers/net/ethernet/xscale/ptp_ixp46x.c
View File

@@ -232,6 +232,9 @@ static struct ixp_clock ixp_clock;
int ixp46x_ptp_find(struct ixp46x_ts_regs *__iomem *regs, int *phc_index)
{
if (!cpu_is_ixp46x())
return -ENODEV;
*regs = ixp_clock.regs;
*phc_index = ptp_clock_index(ixp_clock.ptp_clock);