[Patch 4/6] Modify process and processor handling code to recognise hardware debug registers

[David Gibson]

On Thu, Jun 18, 2009 at 11:26:23PM +0530, K.Prasad wrote:
> On Wed, Jun 17, 2009 at 02:14:20PM +1000, David Gibson wrote:
> > On Wed, Jun 10, 2009 at 02:38:18PM +0530, K.Prasad wrote:
[snip]
> > > @@ -254,8 +255,10 @@ void do_dabr(struct pt_regs *regs, unsig
> > >  			11, SIGSEGV) == NOTIFY_STOP)
> > >  		return;
> > >  
> > > +#ifndef CONFIG_PPC64
> > >  	if (debugger_dabr_match(regs))
> > >  		return;
> > > +#endif
> > 
> > Won't this disable the check for breakpoints set by xmon - but I don't
> > see anything in this patch series to convert xmon to use the new
> > breakpoint interface instead.
> 
> As noted by me here:
> http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-May/071832.html the
> Xmon integration is pending. When I tried to study and integrate Xmon, I
> found that the HW Breakpoint triggering was broken as of 2.6.29 kernel
> (tested on a Power5 box).
> 
> This would mean that if Xmon's hardware breakpoint infrastructure is
> used in tandem with the given breakpoint interfaces, they would conflict
> with each other resulting in difficult-to-predict behaviour (the last to
> grab the register will use it).
> 
> I think that tidying up do_dabr() is best done along with Xmon
> integration.

Hmm, ok.

-- 
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				| _way_ _around_!
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