From cb9e3cff73455b100966b04871fb3817feed4b7c Mon Sep 17 00:00:00 2001 From: vanhoefm Date: Fri, 10 Jun 2022 19:03:01 +0200 Subject: [PATCH] README: Explain printk in firmware --- README.md | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/README.md b/README.md index c728313..7c7c26a 100644 --- a/README.md +++ b/README.md @@ -133,6 +133,16 @@ You can inject A-MPDUs using ModWifi by adding a special trailer to injected fra The firmware will then automatically aggregate these three frames into an A-MPDU. For background, see the function [`modwifi_txampdu_check`](https://github.com/vanhoefm/modwifi-ath9k-htc/blob/research/target_firmware/wlan/if_owl.c#L1573). +#### Firmware Debugging + +There is support to add short debug messages to the firmware. You can access these debug messages as follows: + + root@ubuntu:~$ mount -t debugfs none /sys/kernel/debug + root@ubuntu:~$ cd /sys/kernel/debug/ieee80211/phy*/ath9k_htc/ + root@ubuntu:~$ cat dmesg + +In the firmware you can make calls to [printk](https://github.com/vanhoefm/modwifi-ath9k-htc/blob/f01cbd56f160bd3f593fb71324c424241ea604ad/target_firmware/wlan/attacks.c#L302) to debug the firmware. Because the firmware has a low amount of memory, it is recommended to only add short debug messages. The debug log is implemented as a ringbuffer on the firmware, meaning new debug messages will overwrite old messages to prevent running out of memory. + ## Troubleshooting If an attack or device is not working, you can try the following steps to get it working again: