using gdb/kgdb

[Charles Krinke]

I am having a little trouble with kgdb in an 8541 kernel. 

The kernel is compiled with CONFIG_DEBUG_KERNEL, CONFIG_KGDB, CONFIG_KGDB_TTYS1 all defined and I can boot it to the point where it is waiting for a gdb connection and it does make a connection. I have kernel command line that contains "kgdb=ttyS1,115200,halt kgdbwait" in it and this appears to be working fine and the output looks like this.

MMU:enterJCSSU'ëinit
MMU:mapin
MMU:setio
MMU:exit
begin start_kernel
setup_arch: enter
setup_arch: kgdb breakpoint

At this point, from the cross-compiled gdb on a host, if I invoke gdb with vmlinux as an argument, the PC is zero.

$ ppc-gdb vmlinux

(gdb)set remotebaud 115200

(gdb)target remote /dev/ttyUSB0

(gdb)0x00000000 in ?? ()

If I invoke the cross-compiled gdb without vmlinux as an argument, I get a better looking pc, like this

$ ppc-gdb 

(gdb)set remotebaud 115200

(gdb)target remote /dev/ttyUSB0

(gdb)0xc00071f4 in ?? ()

But in neither case can I 'step' or 'next' as gdb merely replies

Cannot find bounds of current function.

Can someone offer a spot of advice to this despicable condition?

Charles

p.s. I apologize if this comes out html as I am using the companies webmail interface from home.