Kernel module probing on ARM / cross-compilation

["Turgis, Frederic" <f-turgis at ti dot com>]

Hi,

Here is a status on probing a kernel module with systemtap with cross-compiled system. Goal is to ensure observations are correct before updating omappedia wiki and follow-up with some old posts such as http://sourceware.org/ml/systemtap/2011-q3/msg00144.html:

- platform is OMAP4, systemtap v1.7 / elfutils 0.148. Distribution is Android cross-compiled on an Ubuntu host, i.e. the first 4 steps are performed on host and output is run on target.

- module xxx.ko was probed through module("xxx").function("yyy") syntax

- module required to be copied inside kernel folder. I was not able to indicate a path where to look at debuginfo on host. Tried SYSTEMTAP_DEBUGINFO_PATH but it did not seem to help.

- module must obviously not be stripped of its symbols.

- basics and more seemed to work well: probefunc(), backtracing, $$parms, ... In the generated code, addresses and sections (.text) were correctly defined.

So except the path topic, there was no gap. Just had to browse the given Makefile to identify where symbols were stripped.



Regards
Fred

OMAP Platform Business Unit - System Platform Engineering - Platform & Product Entitlement



Texas Instruments France SA, 821 Avenue Jack Kilby, 06270 Villeneuve Loubet. 036 420 040 R.C.S Antibes. Capital de EUR 753.920