[RFC] [PATCH] powerpc: Add MSR_DE to MSR_KERNEL

[Scott Wood]

On Fri, Jul 20, 2012 at 10:37:17AM +0200, Joakim Tjernlund wrote:
> Zang Roy-R61911 <r61911 at freescale.com> wrote on 2012/07/20 10:27:52:
> >
> >
> >
> > > -----Original Message-----
> > > From: linuxppc-dev-bounces+tie-fei.zang=freescale.com at lists.ozlabs.org
> > > [mailto:linuxppc-dev-bounces+tie-fei.zang=freescale.com at lists.ozlabs.org]
> > > On Behalf Of Joakim Tjernlund
> > > Sent: Friday, June 01, 2012 6:36 AM
> > > To: Wood Scott-B07421
> > > Cc: linuxppc-dev at ozlabs.org; Dan Malek; Bob Cochran; Support
> > > Subject: Re: [RFC] [PATCH] powerpc: Add MSR_DE to MSR_KERNEL
> > >
> > > It just occurred to me that you guys have this already in your Linux SDK so
> > > it can't be that bad.
> > No. MSR_DE is ONLY added when using CW debug in SDK.
> > Roy
> >
> 
> Yes, and I later found that user space debugging is busted if you turn on MSR_DE in
> kernel.

So, how should we handle the CONFIG_BDI_SWITCH patch?  It seems like it
should at least have a warning in the kconfig help text that it breaks
userspace debugging (to the point of causing a kernel oops if it's
tried).  Or maybe it can deselect CONFIG_PPC_ADV_DEBUG_REGS?

It'd also be nice to keep things like this, that are a consequence of how
external debug works on e500, separate from the Abatron-specific stuff.

-Scott