Hi Hauke,
sorry for the delayed response, see the answer below.
On 18.01.2025 22:05, Hauke Mehrtens wrote:
On 1/12/25 15:09, Sergey Ryazanov wrote:
It looks like VRX518 returns phys addr of data buffer in the 'data_ptr'
field of the RX descriptor and an actual data offset within the buffer
in the 'byte_off' field. In order to map the phys address back to
virtual we need the original phys address of the allocated buffer.
In the same driver applies offset to phys address before the mapping,
what leads to WARN_ON triggering in plat_mem_virt() function with
subsequent kernel panic:
WARNING: CPU: 0 PID: 0 at .../sw_plat.c:764 0xbf306cd0
[vrx518_tc@8af9f5d0+0x25000]
...
Unable to handle kernel NULL pointer dereference at virtual address
00000000
pgd = aff5701e
[00000000] *pgd=00000000
Internal error: Oops: 5 [#1] SMP ARM
Noticed in ATM mode, when chip always returns byte_off = 4.
In order to fix the issue, pass the phys address to plat_mem_virt() as
is and apply byte_off later on mapped virtual address when copying RXed
data into the skb.
Run tested with FRITZ!Box 7530 on both ADSL and VDSL (thanks Jan) links.
Fixes: 474bbe23b7 ("kernel: add Intel/Lantiq VRX518 TC driver")
Tested-by: Jan Hoffmann <j...@3e8.eu> # VDSL link
Reported-and-tested-by: nebibigo...@yandex.ru # ADSL link
Signed-off-by: Sergey Ryazanov <ryazanov....@gmail.com>
---
package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch
b/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch
index edc97998b7..0d97ec4d5f 100644
--- a/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch
+++ b/package/kernel/lantiq/vrx518_tc/patches/200-swplat.patch
@@ -855,7 +855,7 @@ This replaces it by a basic working implementation.
- continue;
+
+ // this seems to be a pointer to a DS PKT buffer
-+ phyaddr = desc->data_ptr + desc->byte_off;
++ phyaddr = desc->data_ptr;
+ ptr = plat_mem_virt(phyaddr);
+
+ len = desc->data_len;
@@ -871,7 +871,7 @@ This replaces it by a basic working implementation.
- ring_idx_inc(rxout, idx);
+
+ dst = skb_put(skb, len);
-+ memcpy(dst, ptr, len);
++ memcpy(dst, ptr + desc->byte_off, len);
+
+ priv->tc_ops.recv(g_plat_priv->netdev, skb);
+
Is the len over the full buffer including the byte_off?
Nope. According to my observations, the descriptor length contains only
the packet length.
If it does not contain the byte_off you should add it to the len in the
dma_sync_single_range_for_cpu() call.
Nice catch! To sync the whole area we need the sum of the data offset
and the data length. Will update and send the V4.
--
Sergey
_______________________________________________
openwrt-devel mailing list
openwrt-devel@lists.openwrt.org
https://lists.openwrt.org/mailman/listinfo/openwrt-devel
