systemtap ARM port status

[Anderson Lizardo]

On 6/1/07, Quentin Barnes <qbarnes@urbana.css.mot.com> wrote:
> Note though that the ARM port work doesn't yet include all the
> changes to get the testsuite to run on an ARM platform.  I'm still
> working on those and will be submitting them to the list soon.

Nice! Have you already tested some of the example .stp scripts from
the systemtap package on ARM?

> Well, for now I'm running completely native.  Yes, that's very, very
> painful to run gcc and g++ on such a board with an NFS mounted file
> system and NFS mounted swap file over loopback.  It can take four
> hours of wall time to compile and link the "stap" binary and the
> better part of a day to run the full testsuite.

How do you solve the problem of having the kernel and the modules
compiled with the same   toolchain? Do you also compile the kernel on
ARM?

> There is another group who's adding cross-target support to Systemtap:
> http://tree.celinuxforum.org/CelfPubWiki/ELC2007TechnicalShowcase?action=AttachFile&do=get&target=SystemTap_Poster.ppt
>
> I have had only limited contact with them so far.  I would like to
> have more and come up to speed on their work.

Thanks for the link. We will look into it once we have some
implementation to work on :)

> To back up a bit, where are you getting the ARM Kprobes port from?
> Is this based on Sagar and my work I posted to the ARM Linux kernel
> mailing list recently, or some other ARM Kprobes port?

We are using the patches you sent to LKML a while ago. Any changes to
those patches since then?

BTW, we had a couple of problems getting them to compile for OMAP and
QEMU (emulated Versatile platform):

- errors about undefined "__asm__" macros on kprobes-decode.c. To
workaround, we changed all occurrences to "asm".
- an error about undefined "__LINUX_ARM__ARCH___" (note the additional
underlines) on kprobes-decode.c. We changed it to
"__LINUX_ARM_ARCH__". Maybe it was a typo?
- we removed the "___attribute___((naked))" atributte from
kretprobe_trampoline_holder() since our compiler (CodeSourcery
2006q3-27) didn't seem to like it)

After patching these issues, we could get some simple tests from
kprobes.txt to run.

Regards,
-- 
Anderson Lizardo
Open Source Mobile Research Center - OSMRC
Nokia Institute of Technology - INdT
Manaus - Brazil