linux.git/drivers/net/dsa/mxl862xx, branch master

net: dsa: mxl862xx: fix use-after-free of DSA ports in crc_err_work

2026-06-25T00:51:11+00:00

Upon an MDIO CRC error mxl862xx_crc_err_work_fn() walks the DSA ports
and closes the CPU port conduits:

	dsa_switch_for_each_cpu_port(dp, priv->ds)
		dev_close(dp->conduit);

mxl862xx_remove() unregisters the switch before cancelling this work:

	set_bit(MXL862XX_FLAG_WORK_STOPPED, &priv->flags);
	cancel_delayed_work_sync(&priv->stats_work);
	dsa_unregister_switch(ds);
	mxl862xx_host_shutdown(priv);

dsa_unregister_switch() frees the dsa_port objects. If a CRC error
schedules the work during teardown it can run after the ports have been
freed and dereference freed memory.

Guard the port walk with MXL862XX_FLAG_WORK_STOPPED, which is already set
before dsa_unregister_switch(). DSA tears the ports down under
rtnl_lock(), so checking the flag under rtnl_lock() means the work either
runs before teardown and sees valid ports, or runs afterwards, observes
the flag and skips the walk. This mirrors the host_flood_work handler,
which skips torn-down ports under rtnl_lock().

Link: https://sashiko.dev/#/patchset/cover.1780968180.git.daniel%40makrotopia.org?part=2
Fixes: a319d0c8c8ce ("net: dsa: mxl862xx: add CRC for MDIO communication")
Signed-off-by: Daniel Golle 
Link: https://patch.msgid.link/5e55169926c02f2b914e5ada529d7453b943cda4.1781702256.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: avoid unaligned 16-bit access in api_wrap

2026-06-25T00:51:11+00:00

The MXL862XX_API_* macros pass the address of a stack-allocated, __packed
firmware-ABI struct to mxl862xx_api_wrap() as a void *. The struct has an
alignment of 1, so the compiler is free to place it at an odd address.

mxl862xx_api_wrap() reinterprets that buffer as a __le16 * and accesses it
with data[i], for which the compiler assumes the natural 2-byte alignment
of __le16 and emits aligned 16-bit loads/stores (e.g. lhu/sh on MIPS).
When the buffer lands on an odd address these fault on architectures that
do not support unaligned access, such as MIPS32.

-Waddress-of-packed-member does not catch this: the packed origin is
laundered through the void * parameter, so the cast inside api_wrap looks
alignment-safe to the compiler and no warning is emitted.

Use get_unaligned_le16()/put_unaligned_le16() for the three 16-bit word
accesses. The byte accesses (*(u8 *)&data[i], crc16()) are already safe
and are left unchanged.

Link: https://sashiko.dev/#/patchset/cover.1781319534.git.daniel%40makrotopia.org?part=4
Fixes: 23794bec1cb6 ("net: dsa: add basic initial driver for MxL862xx switches")
Signed-off-by: Daniel Golle 
Link: https://patch.msgid.link/599327521db465a534d277de53ab9b6cac01928b.1781702256.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: add support for SerDes ports

2026-06-16T00:18:01+00:00

The MxL862xx has two XPCS/SerDes interfaces (XPCS0 for ports 9-12,
XPCS1 for ports 13-16). Each can operate in various single-lane modes
(SGMII, 1000Base-X, 2500Base-X, 10GBase-R, 10GBase-KR, USXGMII) or as
QSGMII or 10G_QXGMII providing four sub-ports per interface.

Implement phylink PCS operations using the firmware's XPCS API:

- pcs_enable/pcs_disable: refcount the sub-ports sharing an XPCS
and power it down once the last sub-port is released.
- pcs_config: configure negotiation mode and CL37/SGMII advertising.
- pcs_get_state: read link state and the link-partner ability word
from firmware and decode using phylink's standard CL37, SGMII, and
USXGMII decoders.
- pcs_an_restart: restart CL37 or CL73 auto-negotiation.
- pcs_link_up: force speed/duplex for SGMII.
- pcs_inband_caps: report per-mode in-band status capabilities.

Register a PCS instance for each SerDes interface and
QSGMII/10G_QXGMII sub-ports during setup. Advertise the supported
interface modes in phylink_get_caps based on port number.

Firmware older than 1.0.84 lacks the XPCS API and instead configures
the SerDes itself, using defaults stored in flash. mac_select_pcs()
returns NULL in that case while the single-lane interface modes stay
advertised, so a CPU port keeps working in the firmware-configured
mode.

Lacking support for expressing PHY-side role modes in Linux only the
MAC-side of SGMII, QSGMII, USXGMII and 10G_QXGMII are implemented for
now.

Signed-off-by: Daniel Golle
Link: https://patch.msgid.link/736e4df02e4cb8c530c1670cbe7efac20b5d696d.1781319534.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: move API macros to mxl862xx-host.h

2026-06-16T00:18:01+00:00

Move the MXL862XX_API_WRITE, MXL862XX_API_READ and
MXL862XX_API_READ_QUIET convenience macros from mxl862xx.c to
mxl862xx-host.h next to the mxl862xx_api_wrap() prototype they wrap.
This makes them available to other compilation units that include
mxl862xx-host.h, which is needed once the SerDes PCS code in
mxl862xx-phylink.c also calls firmware commands.

No functional change.

Signed-off-by: Daniel Golle 
Reviewed-by: Maxime Chevallier 
Link: https://patch.msgid.link/914f57931e79cc3932a9f32813465c08d29cf4bf.1781319534.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: move phylink stubs to mxl862xx-phylink.c

2026-06-16T00:18:00+00:00

Move the phylink MAC operations and get_caps callback from mxl862xx.c
into a dedicated mxl862xx-phylink.c file. This prepares for the SerDes
PCS implementation which adds substantial phylink/PCS code -- keeping
it in a separate file avoids function-position churn in the main
driver file.

No functional change.

Signed-off-by: Daniel Golle 
Reviewed-by: Maxime Chevallier 
Link: https://patch.msgid.link/fb9336de94bef47a0834287cbca87954e5e4c795.1781319534.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: store firmware version for feature gating

2026-06-16T00:18:00+00:00

Query the firmware version at init (already done in wait_ready),
cache it in priv->fw_version, and provide MXL862XX_FW_VER_MIN()
for version-gated code paths throughout the driver.

MXL862XX_FW_VER() packs major/minor/revision into a u32 with
bitwise shifts so that versions compare with natural ordering,
independent of host endianness.

Signed-off-by: Daniel Golle 
Reviewed-by: Andrew Lunn 
Link: https://patch.msgid.link/91a26a8ffeaa2ce1729f98347e93e779973976bb.1781319534.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: implement .get_stats64

2026-04-13T23:46:43+00:00

Poll free-running firmware RMON counters every 2 seconds and accumulate
deltas into 64-bit per-port statistics. 32-bit packet counters wrap
in ~220s at 10 Gbps line rate with minimum-size frames; the 2s polling
interval provides a comfortable margin. The .get_stats64 callback
forces a fresh poll so that counters are always up to date when queried.

Signed-off-by: Daniel Golle 
Link: https://patch.msgid.link/fa38548ba05866879e8912721edc91947ce4ff12.1775951347.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: add ethtool statistics support

2026-04-13T23:46:43+00:00

The MxL862xx firmware exposes per-port RMON counters through the
RMON_PORT_GET command, covering standard IEEE 802.3 MAC statistics
(unicast/multicast/broadcast packet and byte counts, collision
counters, pause frames) as well as hardware-specific counters such
as extended VLAN discard and MTU exceed events.

Add the RMON counter firmware API structures and command definitions.
Implement .get_strings, .get_sset_count, and .get_ethtool_stats for
legacy ethtool -S support. Implement .get_eth_mac_stats,
.get_eth_ctrl_stats, and .get_pause_stats for the standardized
IEEE 802.3 statistics interface.

Signed-off-by: Daniel Golle 
Link: https://patch.msgid.link/480be14d5ed51f3db7b1681b298044dbf8e87494.1775951347.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: implement VLAN functionality

2026-04-10T23:03:44+00:00

Add VLAN support using both the Extended VLAN (EVLAN) engine and the
VLAN Filter (VF) engine in a hybrid architecture that allows a higher
number of VIDs than either engine could achieve alone.

The VLAN Filter engine handles per-port VID membership checks with
discard-unmatched semantics. The Extended VLAN engine handles PVID
insertion on ingress (via fixed catchall rules) and tag stripping on
egress (2 rules per untagged VID). Tagged-only VIDs need no EVLAN
egress rules at all, so they consume only a VF entry.

Both engines draw from shared 1024-entry hardware pools. The VF pool
is divided equally among user ports for VID membership, while the
EVLAN pool is partitioned into small fixed-size ingress blocks (7
entries of catchall rules per port) and fixed-size egress blocks for
tag stripping.

With 5 user ports this yields up to 204 VIDs per port (limited by VF),
of which up to 98 can be untagged (limited by EVLAN egress budget).
With 9 user ports the numbers are 113 total and 53 untagged.

Wire up .port_vlan_add, .port_vlan_del, and .port_vlan_filtering.
Reprogram all EVLAN rules when the PVID or filtering mode changes.
Detach blocks from the bridge port before freeing them on bridge leave
to satisfy the firmware's internal refcount.

Future optimizations could increase VID capacity by dynamically sizing
the egress EVLAN blocks based on actual per-port untagged VID counts
rather than worst-case pre-allocation, or by sharing EVLAN egress and
VLAN Filter blocks across ports with identical VID sets.

Signed-off-by: Daniel Golle
Link: https://patch.msgid.link/9be29637675342b109a85fa08f5378800d9f7b78.1775581804.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski

net: dsa: mxl862xx: don't skip early bridge port configuration

2026-04-10T23:03:44+00:00

mxl862xx_bridge_port_set() is currently guarded by the
mxl8622_port->setup_done flag, as the early call to
mxl862xx_bridge_port_set() from mxl862xx_port_stp_state_set() would
otherwise cause a NULL-pointer dereference on unused ports which don't
have dp->cpu_dp despite not being a CPU port.

Using the setup_done flag (which is never set for unused ports),
however, also prevents mxl862xx_bridge_port_set() from configuring
user ports' single-port bridges early, which was unintended.

Fix this by returning early from mxl862xx_bridge_port_set() in case
dsa_port_is_unused().

Fixes: 340bdf984613c ("net: dsa: mxl862xx: implement bridge offloading")
Signed-off-by: Daniel Golle 
Link: https://patch.msgid.link/15962aac29ebe0a6eb77565451acff880c41ef33.1775581804.git.daniel@makrotopia.org
Signed-off-by: Jakub Kicinski