From: David Gibson <david@gibson.dropbear.id.au>
To: srikanth krishnakar <skrishnakar@gmail.com>
Cc: Linuxppc-dev@ozlabs.org, Linuxppc-embedded@ozlabs.org
Subject: Re: Initialize DBCR0 for PPC440 targets
Date: Wed, 20 May 2009 09:53:02 +1000 [thread overview]
Message-ID: <20090519235302.GA6333@yookeroo.seuss> (raw)
In-Reply-To: <6213bc560905190608j73f4191fxbd94158a2b1740c0@mail.gmail.com>
On Tue, May 19, 2009 at 06:38:53PM +0530, srikanth krishnakar wrote:
> Hi,
>
> kernel- 2.6.29
> Debug technique: KGDB
>
> The PowerPC kernel does not initialize the PPC440 DBCR0 register. This
> prevents the use of software breakpoints in case of internal debug
> mode. Looking into head_fsl_booke.S for initialization of DBCR0 is
> used by boot-loaders.
> It seems head_44x.S lacks this step of DBCR0 register initialization.
> So fixing this with initializing the DBCR0 register as shown below :
>
> Subject: [PATCH] powerpc: 44x: Initialize DBCR0 for targets not having
> bootloader
>
> The kernel does not initialize the PPC440 DBCR0 register.
> This prevents (among other things) the use of software
> breakpoints with GDB. The boot loaders probably do initialize
> this but few targets run without a boot loader
Um.. how does this prevent the use of software breakpoints with gdb?
The trap instructions still work with IDM==0.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
next prev parent reply other threads:[~2009-05-19 23:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-19 13:08 Initialize DBCR0 for PPC440 targets srikanth krishnakar
2009-05-19 23:53 ` David Gibson [this message]
2009-05-20 5:50 ` srikanth krishnakar
2009-05-20 6:00 ` David Gibson
2009-05-20 6:14 ` srikanth krishnakar
2009-05-25 7:04 ` Benjamin Herrenschmidt
2009-05-26 2:23 ` David Gibson
2009-05-25 6:30 ` srikanth krishnakar
2009-05-25 6:39 ` Grant Likely
2009-05-25 6:51 ` srikanth krishnakar
2009-05-26 15:11 ` John Linn
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