Re: [Valgrind-developers] ptrace(2) unsupported in Valgrind for the Power architecture.

[Philippe W. <phi...@sk...>]

On Thu, 2013-05-16 at 15:12 +0000, Paralkar Anmol-B07584 wrote:
> Hello,
> 
>  I am trying to run GDB on my port of Valgrind (3.8.1) to Freescale's e500v2 SPE ISA on linux (3.x),
>  to test the port, Valgrind, and hopefully, use the findings to fix issues in GDB itself. GDB runs
>  on Valgrind till the point that it makes a ptrace(2) call, which is reported as unsupported.
>  As instructed, I began by following the direction given in the file README_MISSING_SYSCALL_OR_IOCTL,
>  and found that there used to be ptrace support (in coregrind/m_syswrap/syswrap-ppc32-linux.c) - but,
>  it is all commented out. So, ptrace is unsupported on ppc-{32, 64}. (I looked at the svn log,
>  but did not find any reason why. Also looked up Bugzilla). I did find:
> 
>  http://article.gmane.org/gmane.comp.debugging.valgrind/10225/match=ptrace
> 
>  and perhaps in some way related:
> 
>  http://thread.gmane.org/gmane.comp.debugging.valgrind.devel/819
> 
>  Please could you help me understand the issues involved in getting ptrace(2) working on POWER again?

You can remove "again" from your question, it has never worked :).
The ppc32/ppc64 syswrap files have been done by copying the
x86 (or amd64) files, and updating part of these,
and commenting the rest, waiting for some courageous person
to do the work.
The ptrace commented code looks just to be the x86/amd64 code
(e.g. it references the i387 floating points registers, which I doubt
was available one day on ppc32 :).

So, you "just" have to implement the ptrace pre/post wrapper
"almost from scratch".

Philippe