Re: [patch] "single step" atomic instruction sequences as a whole.

Luis Machado
2007-02-07T13:10:34Z

Hi Emi,

It's great that we have someone working on this issue also.

What's exactly been modified on your patch for single stepping of atomic
instruction sequences? Does it handle the issues that you have mentioned
about thread hopping check?

Regards,
Luis

On Tuesday 06 February 2007 10:11, Emi SUZUKI wrote:
> Hello Luis and members,
>
> I am working on Linux running on PlayStation 3, and on Fedora Core 5
> for PowerPC running on our own hardware equipped with 'Cell' CPU.
> I have also been annoyed by this problem for months, because the main
> core of Cell is PowerPC.
>
> As far as I know, the patch by Paul has a problem mentioned by the
> messages below:
> http://sourceware.org/ml/gdb-patches/2006-09/msg00060.html
> http://sourceware.org/ml/gdb-patches/2006-09/msg00097.html
> http://sourceware.org/ml/gdb-patches/2006-11/msg00049.html
> http://sourceware.org/ml/gdb-patches/2006-11/msg00074.html
>
> And the idea is a bit confusing for me...
>
> I just thought that SOFTWARE_SINGLE_STEP_P should indicate if the
> target will do software single-stepping at the next time it proceed.
> And all the architectures which should skip atomic sequences of
> instructions by themselves need to implement are
> SOFTWARE_SINGLE_STEP_P to check if the skipping is needed, and
> SOFTWARE_SINGLE_STEP to actually skip the sequence.
> # I remember someone said that ARM and MIPS have a similar problem.
>
> As a effect of the change above, the return value of SOFTWARE_SINGLE_STEP_P
> cannot be used as the condition of thread hopping check or removing
> a software single-stepping breakpoint on handle_inferior_event: it
> may not be welcomed.
>
> Anyway, I will attach a patch applied on our environment. It's for
> CVS head.
> Since it's my first time of posting here, any comments are very
> appreciated.
>
> P.S.
> I have not completed the legal process of copyright assignment, and
> unfortunately the boss said to me that it will take months...
> Please point me if the patch can be applied and surely needs an
> assignment, I will make them hurry.