Hi David, Just to correct the statements : How the DBCR0 is initialized on targets that don't use boot loaders ?
-Srikant On Wed, May 20, 2009 at 11:30 AM, David Gibson <da...@gibson.dropbear.id.au> wrote: > On Wed, May 20, 2009 at 11:20:46AM +0530, srikanth krishnakar wrote: >> Hi David, >> >> I am not sure how the IDM behaves on few of PPC440 targets which don't >> have boot loaders. I have a reference for your question: >> >> http://www.nabble.com/Question-about-DBCR0-initialization-for-440-td23049044.html >> >> Without this fix (given patch) I am facing problems with GDB, and >> further target hangs while running gdbserver ! > > That doesn't answer my question. It's not enough to say "this fixes a > problem" you need to explain *how* it fixes the problem. > > And I don't see why IDM would have any effect on *software* > breakpoints. > >> On Wed, May 20, 2009 at 5:23 AM, David Gibson >> <da...@gibson.dropbear.id.au> wrote: >> > 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 > -- "The Good You Do, The Best You GET" Regards Srikanth Krishnakar ********************** _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
