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There are 2 distinct code paths (listed below) in the source code which
set up an injection header for Ocelot(-like) switches. Code path (2)
lacks the QoS class and source port being set correctly. Especially the
improper QoS classification is a problem for the "ocelot-8021q"
alternative DSA tagging protocol, because we support tc-taprio and each
packet needs to be scheduled precisely through its time slot. This
includes PTP, which is normally assigned to a traffic class other than
0, but would be sent through TC 0 nonetheless.
The code paths are:
(1) ocelot_xmit_common() from net/dsa/tag_ocelot.c - called only by the
standard "ocelot" DSA tagging protocol which uses NPI-based
injection - sets up bit fields in the tag manually to account for
a small difference (destination port offset) between Ocelot and
Seville. Namely, ocelot_ifh_set_dest() is omitted out of
ocelot_xmit_common(), because there's also seville_ifh_set_dest().
(2) ocelot_ifh_set_basic(), called by:
- ocelot_fdma_prepare_skb() for FDMA transmission of the ocelot
switchdev driver
- ocelot_port_xmit() -> ocelot_port_inject_frame() for
register-based transmission of the ocelot switchdev driver
- felix_port_deferred_xmit() -> ocelot_port_inject_frame() for the
DSA tagger ocelot-8021q when it must transmit PTP frames (also
through register-based injection).
sets the bit fields according to its own logic.
The problem is that (2) doesn't call ocelot_ifh_set_qos_class().
Copying that logic from ocelot_xmit_common() fixes that.
Unfortunately, although desirable, it is not easily possible to
de-duplicate code paths (1) and (2), and make net/dsa/tag_ocelot.c
directly call ocelot_ifh_set_basic()), because of the ocelot/seville
difference. This is the "minimal" fix with some logic duplicated (but
at least more consolidated).
Fixes: 0a6f17c6ae21 ("net: dsa: tag_ocelot_8021q: add support for PTP timestamping")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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register injection
Problem description
-------------------
On an NXP LS1028A (felix DSA driver) with the following configuration:
- ocelot-8021q tagging protocol
- VLAN-aware bridge (with STP) spanning at least swp0 and swp1
- 8021q VLAN upper interfaces on swp0 and swp1: swp0.700, swp1.700
- ptp4l on swp0.700 and swp1.700
we see that the ptp4l instances do not see each other's traffic,
and they all go to the grand master state due to the
ANNOUNCE_RECEIPT_TIMEOUT_EXPIRES condition.
Jumping to the conclusion for the impatient
-------------------------------------------
There is a zero-day bug in the ocelot switchdev driver in the way it
handles VLAN-tagged packet injection. The correct logic already exists in
the source code, in function ocelot_xmit_get_vlan_info() added by commit
5ca721c54d86 ("net: dsa: tag_ocelot: set the classified VLAN during xmit").
But it is used only for normal NPI-based injection with the DSA "ocelot"
tagging protocol. The other injection code paths (register-based and
FDMA-based) roll their own wrong logic. This affects and was noticed on
the DSA "ocelot-8021q" protocol because it uses register-based injection.
By moving ocelot_xmit_get_vlan_info() to a place that's common for both
the DSA tagger and the ocelot switch library, it can also be called from
ocelot_port_inject_frame() in ocelot.c.
We need to touch the lines with ocelot_ifh_port_set()'s prototype
anyway, so let's rename it to something clearer regarding what it does,
and add a kernel-doc. ocelot_ifh_set_basic() should do.
Investigation notes
-------------------
Debugging reveals that PTP event (aka those carrying timestamps, like
Sync) frames injected into swp0.700 (but also swp1.700) hit the wire
with two VLAN tags:
00000000: 01 1b 19 00 00 00 00 01 02 03 04 05 81 00 02 bc
~~~~~~~~~~~
00000010: 81 00 02 bc 88 f7 00 12 00 2c 00 00 02 00 00 00
~~~~~~~~~~~
00000020: 00 00 00 00 00 00 00 00 00 00 00 01 02 ff fe 03
00000030: 04 05 00 01 00 04 00 00 00 00 00 00 00 00 00 00
00000040: 00 00
The second (unexpected) VLAN tag makes felix_check_xtr_pkt() ->
ptp_classify_raw() fail to see these as PTP packets at the link
partner's receiving end, and return PTP_CLASS_NONE (because the BPF
classifier is not written to expect 2 VLAN tags).
The reason why packets have 2 VLAN tags is because the transmission
code treats VLAN incorrectly.
Neither ocelot switchdev, nor felix DSA, declare the NETIF_F_HW_VLAN_CTAG_TX
feature. Therefore, at xmit time, all VLANs should be in the skb head,
and none should be in the hwaccel area. This is done by:
static struct sk_buff *validate_xmit_vlan(struct sk_buff *skb,
netdev_features_t features)
{
if (skb_vlan_tag_present(skb) &&
!vlan_hw_offload_capable(features, skb->vlan_proto))
skb = __vlan_hwaccel_push_inside(skb);
return skb;
}
But ocelot_port_inject_frame() handles things incorrectly:
ocelot_ifh_port_set(ifh, port, rew_op, skb_vlan_tag_get(skb));
void ocelot_ifh_port_set(struct sk_buff *skb, void *ifh, int port, u32 rew_op)
{
(...)
if (vlan_tag)
ocelot_ifh_set_vlan_tci(ifh, vlan_tag);
(...)
}
The way __vlan_hwaccel_push_inside() pushes the tag inside the skb head
is by calling:
static inline void __vlan_hwaccel_clear_tag(struct sk_buff *skb)
{
skb->vlan_present = 0;
}
which does _not_ zero out skb->vlan_tci as seen by skb_vlan_tag_get().
This means that ocelot, when it calls skb_vlan_tag_get(), sees
(and uses) a residual skb->vlan_tci, while the same VLAN tag is
_already_ in the skb head.
The trivial fix for double VLAN headers is to replace the content of
ocelot_ifh_port_set() with:
if (skb_vlan_tag_present(skb))
ocelot_ifh_set_vlan_tci(ifh, skb_vlan_tag_get(skb));
but this would not be correct either, because, as mentioned,
vlan_hw_offload_capable() is false for us, so we'd be inserting dead
code and we'd always transmit packets with VID=0 in the injection frame
header.
I can't actually test the ocelot switchdev driver and rely exclusively
on code inspection, but I don't think traffic from 8021q uppers has ever
been injected properly, and not double-tagged. Thus I'm blaming the
introduction of VLAN fields in the injection header - early driver code.
As hinted at in the early conclusion, what we _want_ to happen for
VLAN transmission was already described once in commit 5ca721c54d86
("net: dsa: tag_ocelot: set the classified VLAN during xmit").
ocelot_xmit_get_vlan_info() intends to ensure that if the port through
which we're transmitting is under a VLAN-aware bridge, the outer VLAN
tag from the skb head is stripped from there and inserted into the
injection frame header (so that the packet is processed in hardware
through that actual VLAN). And in all other cases, the packet is sent
with VID=0 in the injection frame header, since the port is VLAN-unaware
and has logic to strip this VID on egress (making it invisible to the
wire).
Fixes: 08d02364b12f ("net: mscc: fix the injection header")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.
Acked-by: Alex Elder <elder@linaro.org>
Reviewed-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Reviewed-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230727014944.3972546-1-robh@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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ocelot_fdma_receive_skb should return false if an unexpected
value is returned by pskb_trim.
Signed-off-by: Yuanjun Gong <ruc_gongyuanjun@163.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Accidentally noticed, that this driver is the only user of
while (time_after(jiffies...)).
It looks like typo, because likely this while loop will finish after 1st
iteration, because time_after() returns true when 1st argument _is after_
2nd one.
There is one possible problem with this poll loop: the scheduler could put
the thread to sleep, and it does not get woken up for
OCELOT_FDMA_CH_SAFE_TIMEOUT_US. During that time, the hardware has done
its thing, but you exit the while loop and return -ETIMEDOUT.
Fix it by using sane poll API that avoids all problems described above
Fixes: 753a026cfec1 ("net: ocelot: add FDMA support")
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220706132845.27968-1-paskripkin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Switch all Ethernet drivers which use custom napi weights
to the new API.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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dma_addr was declared using DEFINE_DMA_UNMAP_ADDR() which requires to
use dma_unmap_addr() to access it.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 753a026cfec1 ("net: ocelot: add FDMA support")
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Ethernet frames can be extracted or injected autonomously to or from
the device’s DDR3/DDR3L memory and/or PCIe memory space. Linked list
data structures in memory are used for injecting or extracting Ethernet
frames. The FDMA generates interrupts when frame extraction or
injection is done and when the linked lists need updating.
The FDMA is shared between all the ethernet ports of the switch and
uses a linked list of descriptors (DCB) to inject and extract packets.
Before adding descriptors, the FDMA channels must be stopped. It would
be inefficient to do that each time a descriptor would be added so the
channels are restarted only once they stopped.
Both channels uses ring-like structure to feed the DCBs to the FDMA.
head and tail are never touched by hardware and are completely handled
by the driver. On top of that, page recycling has been added and is
mostly taken from gianfar driver.
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Co-developed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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