BDI2000 and failed MMU translations

Gessner, Matt mattg at
Thu Jan 24 09:55:13 EST 2002


This still doesn't solve my problem.

In the Makefile:
	CONFIG_KERNEL = -g -ggdb

In mpc860.cnf for the bdi:
	MMU XLAT 0xc0000000 (this is the default BTW)
	PTBASE	0xf0

On the BDI:
	bi 0xc0157640 (start_kernel)

Now, start gdb w/ vmlinux
(gdb) target remote bdi:2001
(gdb) br scc_enet_init

On the BDI it says:
*** MMU: address translation for 0xC015ECB8 failed
(gdb) c
warning: Cannot insert breakpoint 1:
Error accessing memory address 0xc015ecb8: Operation not permitted

I'm using gdb 5.0.

Does this shed any more light?

TIA Dan and all,



> -----Original Message-----
> From: Dan Malek [mailto:dan at]
> Sent: Wednesday, January 23, 2002 5:51 PM
> To: Gessner, Matt
> Cc: 'Linux PPC'
> Subject: Re: BDI2000 and failed MMU translations
> Gessner, Matt wrote:
> > It's straight 2_4.  I wasn't stopping at start_kernel though.
> You don't need to stop anywhere unless there are some breakpoints
> you want to set for early debug.
> > I don't have PTBASE set up.
> You need:
> 	MMU XLAT 0xc0000000
> 	PTBASE 0x000000f0
> The newer kernels initialize the page table pointers for the BDI2000,
> so ignore comments about stopping and setting values.  We went through
> several iterations of implementation, so anything written about how to
> do this manually is probably wrong :-).
> > ...... I'm going to
> > break at start kernel FIRST, then connect with BDI, then
> > see if I can look at my data.
> How do you break and then connect the BDI?  You need the BDI
> connected to set and trap the breakpoint.
> Have fun.
> 	-- Dan

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