14:48 <ggherdov> Hello, is there a way to call a kernel function from a systemtap probe? There are a few functions that read static data, and sometimes I want to see their output.

14:48 <ggherdov> Example: pm_qos_request() from kernel/power/qos.c which gives the current QoS value for power management, or acpi_evaluate_object() from drivers/acpi/acpica/nsxfeval.c which reads ACPI tables

14:48 <ggherdov> I could write a module to call them, but can I do that with a quick systemtap script?

14:54 <fche> ggherdov, embedded-c

14:55 <fche> see the /usr/share/systemtap/tapset/linux *.stp files for many examples of doing the same

14:55 <fche> note: the EMBEDDED C section in the [man stap] discusses security/safety implications. These are profound -- embedded-C code runs with zero stap-side protection, so that burden is on your own shoulders.

15:00 <ggherdov> fche: amazing! thanks for the pointer. Yeah sure I understand I can mess things up, that's why I precised that I'm just going to run some "getter" kind of functions

15:01 <fche> see also the tapset/*GUIDE* doc files, it covers constraints a little more

15:01 <ggherdov> ok

19:49 <irker046> systemtap: fche systemtap.git:refs/heads/master * release-4.0-111-g5e50524 / tapsets.cxx: PR24199: at pass-2 verbosity > 3, trace $var error-chaining events http://tinyurl.com/y3l5rt75

19:49 <irker046> systemtap: fche systemtap.git:refs/heads/master * release-4.0-110-g40f855f / loc2stap.cxx: PR24199: loc2stap: propagate dwarf DIE() source locations better http://tinyurl.com/yxwnsas8

19:49 <irker046> systemtap: fche systemtap.git:refs/heads/master * release-4.0-112-gd36f6fe / elaborate.cxx elaborate.h: PR24199: don't use exceptions to signal type-resolution failures http://tinyurl.com/yxo4uabz