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

On Fri, Jul 20, 2012 at 10:37:17AM +0200, Joakim Tjernlund wrote:

Zang Roy-R61911 [off-list ref] wrote on 2012/07/20 10:27:52:

quoted

quoted

-----Original Message-----
From: linuxppc-dev-bounces+tie-fei.zang=freescale.com@lists.ozlabs.org
[mailto:linuxppc-dev-bounces+tie-fei.zang=freescale.com@lists.ozlabs.org]
On Behalf Of Joakim Tjernlund
Sent: Friday, June 01, 2012 6:36 AM
To: Wood Scott-B07421
Cc: linuxppc-dev@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