Is it possible to create, using stap command, a kernel module which accepts arguments

Is it possible to create, using stap command, a kernel module which accepts arguments

[Dmitry Malichenko]

Hello,

could you please help me with one question.
I saw some *.stp scripts which accept arguments, but these arguments
I should pass while running stap command.

Is it possible to write script in such a way, that argument should be
passed while running staprun command?
My goal is using *.ko module with command line argument instead of
recompiling *.stp script for each argument change.

I was looking for such information in manuals, but didn't find.

Thanks in advance,
Dmitry

Re: Is it possible to create, using stap command, a kernel module which accepts arguments

[Frank Ch. Eigler]

Dmitry Malichenko <dmitryml@gmail.com> writes:

> [...] I saw some *.stp scripts which accept arguments, but these
> arguments I should pass while running stap command.  [...]  My goal
> is using *.ko module with command line argument instead of
> recompiling *.stp script for each argument change.

There are two current solutions for this: 

One, use of procfs-based probes to receive parameters at run time from
a probe-specific /proc file:

   probe procfs("file").write { use($value) }

Two, use of module parameters to initialize scalar global variables
with staprun:

   % stap -p4 -e 'global foo,bar   probe begin {printf("%s %d\n",foo, bar)}
   stap_xyz.ko

   % sudo staprun stap_xyz.ko foo=hello bar=4

- FChE

Re: Is it possible to create, using stap command, a kernel module which accepts arguments

[Dmitry Malichenko]

Thanks a lot!

On Thu, Jun 18, 2009 at 7:30 PM, Frank Ch. Eigler<fche@redhat.com> wrote:
> Dmitry Malichenko <dmitryml@gmail.com> writes:
>
>> [...] I saw some *.stp scripts which accept arguments, but these
>> arguments I should pass while running stap command.  [...]  My goal
>> is using *.ko module with command line argument instead of
>> recompiling *.stp script for each argument change.
>
> There are two current solutions for this:
>
> One, use of procfs-based probes to receive parameters at run time from
> a probe-specific /proc file:
>
>   probe procfs("file").write { use($value) }
>
> Two, use of module parameters to initialize scalar global variables
> with staprun:
>
>   % stap -p4 -e 'global foo,bar   probe begin {printf("%s %d\n",foo, bar)}
>   stap_xyz.ko
>
>   % sudo staprun stap_xyz.ko foo=hello bar=4
>
> - FChE
>