Date: Thu, 8 May 1997 16:26:41 +0200 From: j@uriah.heep.sax.de (J Wunsch) To: current@FreeBSD.ORG Subject: Re: Problems using remote gdb Message-ID: <19970508162641.DE47196@uriah.heep.sax.de> In-Reply-To: <199705080042.KAA27367@godzilla.zeta.org.au>; from Bruce Evans on May 8, 1997 10:42:23 %2B1000 References: <199705080042.KAA27367@godzilla.zeta.org.au>
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As Bruce Evans wrote:
> No. The console driver doesn't know about low level consoles. There are
> now 3 layers of consoles:
>
> /dev/console - an ordinary device, written to by syslogd, etc.
> low level part of console driver - used for kernel printfs
> low level consoles - lower than the console driver, called directly
> by i386_gdbstub.
So now, what has the handbook to be changed to?
Bruce, reading the handbook isn't rocket science :), just in case you
don't know how to use Lynx, here's the appropriate paragraphs:
------------------------------------------------------------------------
You should configure the kernel in question with config -g, include
DDB into the configuration, and compile it as usual. This gives a
large blurb of a binary, due to the debugging information. Copy this
kernel to the target machine, strip the debugging symbols off with
strip -x, and boot it using the -d boot option. Connect the first
serial line of the target machine to any serial line of the debugging
host. Now, on the debugging machine, go to the compile directory of
the target kernel, and start gdb:
% gdb -k kernel
GDB is free software and you are welcome to distribute copies of it
under certain conditions; type "show copying" to see the conditions.
There is absolutely no warranty for GDB; type "show warranty" for details.
GDB 4.16 (i386-unknown-freebsd),
Copyright 1996 Free Software Foundation, Inc...
(kgdb)
Initialize the remote debugging session (assuming the first serial
port is being used) by:
(kgdb) target remote /dev/cuaa0
Now, on the target host (that entered DDB right before even starting
the device probe), type:
Debugger("Boot flags requested debugger")
Stopped at Debugger+0x35: movb $0, edata+0x51bc
db> gdb
DDB will respond with:
Next trap will enter GDB remote protocol mode
------------------------------------------------------------------------
Somewhere there, the information about which flags to sio0 are
required and which are useful should go.
--
cheers, J"org
joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)
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