Need more information on uProbes .

Need more information on uProbes .

[Diptopal Basu]

Hi All,

 I am loking for information on uProbes implementation on ARM
architecture , I believe uProbes allows probing in the user space ,
however I am not able to find relevant documentation on the same .

I want to :

   a. Inject variables on running programs un user space during runtime.
   b. Inject code on running programs un user space during runtime .

Please note I am aware that kProbes does the same thing but in kernel
space :( . I am using Linux version 2.6.26.5 )

Regards
Diptopal Basu

Re: Need more information on uProbes .

[Ananth N Mavinakayanahalli]

On Tue, Mar 31, 2009 at 05:55:57PM +0530, Diptopal Basu wrote:
> Hi All,
> 
>  I am loking for information on uProbes implementation on ARM
> architecture , I believe uProbes allows probing in the user space ,
> however I am not able to find relevant documentation on the same .

Uprobes is implemented only for architectures that have utrace support
(x86-32, x86_64, powerpc, s390, but not IA64). Its currently shipped as
part of SystemTap's runtime.

http://sources.redhat.com/git/gitweb.cgi?p=systemtap.git;f=runtime/uprobes/uprobes.txt;hb=HEAD
has some documentation from earlier. The API hasn't changed AFAICS.

For ARM though, the utrace layer needs to be implemented and uprobes
ported over. That's quite some work. AFAIK, nobody is working on it yet.

Ananth

Re: Need more information on uProbes .

[Frank Ch. Eigler]

ananth wrote:

> Uprobes is implemented only for architectures that have utrace support
> (x86-32, x86_64, powerpc, s390, but not IA64). [...]

(HAVE_ARCH_TRACEHOOK is on for ia64, sparc, sh also, so utrace per se
should work there.)

> [...]  For ARM though, the utrace layer needs to be implemented and
> uprobes ported over. [...]

Roland et al., has there been any recent report on
regset/tracehook-on-arm porting?

- FChE

Re: Need more information on uProbes .

[Jim Keniston]

On Tue, 2009-03-31 at 10:09 -0400, Frank Ch. Eigler wrote:
> ananth wrote:
> 
> > Uprobes is implemented only for architectures that have utrace support
> > (x86-32, x86_64, powerpc, s390, but not IA64). [...]
> 
> (HAVE_ARCH_TRACEHOOK is on for ia64, sparc, sh also, so utrace per se
> should work there.)
> 

FWIW, Intel did an ia64 port of uprobes as well, but there wasn't
sufficient followup to get it tucked into systemtap/runtime/uprobes.

Jim

Re: Need more information on uProbes .

[Roland McGrath]

> Roland et al., has there been any recent report on
> regset/tracehook-on-arm porting?

I haven't heard anything.  There are no difficulties in that port AFAIK.
If an ARM arch maintainer (or someone who wants to send them patches) wants
to do it, I'm happy to give advice.


Thanks,
Roland