From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 20 May 2009 09:53:02 +1000 From: David Gibson To: srikanth krishnakar Subject: Re: Initialize DBCR0 for PPC440 targets Message-ID: <20090519235302.GA6333@yookeroo.seuss> References: <6213bc560905190608j73f4191fxbd94158a2b1740c0@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <6213bc560905190608j73f4191fxbd94158a2b1740c0@mail.gmail.com> Cc: Linuxppc-dev@ozlabs.org, Linuxppc-embedded@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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