Subject: Re: [Patch 0/5] PPC64-HWBKPT: Hardware Breakpoint interfaces - ver XXII

From: "K.Prasad" <[email-masked]>
Date: Fri, 4 Jun 2010 12:21:45 +0530

On Wed, Jun 02, 2010 at 09:33:16PM +1000, Paul Mackerras wrote:
> On Fri, May 28, 2010 at 12:09:24PM +0530, K.Prasad wrote:
> 
> > 	Please find a new set of patches that have the following changes.
> 
> Thanks.  There are a couple of minor things still remaining (dangling
> put_cpu in arch_unregister_hw_breakpoint, plus I don't think reusing
> current->thread.ptrace_bps the way you did in patch 5/5 is a good
> idea), but I think at this stage I'll put them in a tree together
> with my latest emulate_step version and then push them to Ben H and/or
> Ingo Molnar once I've done some testing.
> 
> Paul.

Hi Paul,
	Thanks for agreeing to put the patchset into a tree and push it
to the appropriate maintainers.

Meanwhile I tested the per-cpu breakpoints with the new emulate_step
patch (refer linuxppc-dev message-id:
[email-masked]) and they continue to fail
due to emulate_step() failure, in my case, on a "lwz r0,0(r28)"
instruction.

About the latest patchset, given that we chose to ignore extraneous
interrupts for non-ptrace breakpoints, I thought that re-using
current->thread.ptrace_bps as a flag would be efficient than introducing
a new member in 'struct thread_struct' to do the same. I'm not sure if
you foresee any issues with that.

If so, I'd like to send a new patch (rather than a new version of the
complete patchset) to fix it along with the dangling put_cpu() in
arch_unregister_hw_breakpoint() (I forgot to remove parts of the code
between versions XIX and XX).

Thanks,
K.Prasad