Kgdb on Motorola 8451 ppc board

Kgdb on Motorola 8451 ppc board

[Tameen Khan]

I'm trying to run kgdb on  Motorola 8451 ppc board.
I've compiled the kernel with the CONFIG_KGDB option.
The test machine is a linux host. I'm using gdb compiled for target ppc
architecture.
When I try to connect to the dev machine from the test machine, I get the
following error.

(gdb) set remotebaud 9600
(gdb) target remote /dev/ttyS1
Remote debugging using /dev/ttyS1
^^
^^^^Ignoring packet error, continuing...
^^^Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Couldn't establish connection to remote target
Malformed response to offset query, timeout
(gdb)

I've tried other baudrates, but get the same error with them.
Any pointers to where I can get info to get kgdb working for this cross arch
debugging will be helpful.. So far I've searched the web without much luck
on this topic.

Thanks
-Tameen


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Kgdb on Motorola 8451 ppc board

[Tameen Khan]

I'm trying to run kgdb on  Motorola 8451 ppc board.
I've compiled the kernel with the CONFIG_KGDB option.
The test machine is a linux host. I'm using gdb compiled for target ppc
architecture. When I try to connect to the dev machine from the test
machine, I get the following error.

(gdb) set remotebaud 9600
(gdb) target remote /dev/ttyS1
Remote debugging using /dev/ttyS1
^^
^^^^Ignoring packet error, continuing...
^^^Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Couldn't establish connection to remote target
Malformed response to offset query, timeout
(gdb)

I've tried other baudrates, but get the same error with them. Any pointers
to where I can get info to get kgdb working for this cross arch debugging
will be helpful.. So far I've searched the web without much luck on this
topic.

Thanks
-Tameen


** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

Kgdb on Motorola 8451 ppc board

[Tameen Khan]

I'm trying to run kgdb on  Motorola 8451 ppc board.
I've compiled the kernel with the CONFIG_KGDB option.
The test machine is a linux host. I'm using gdb compiled for target ppc
architecture. When I try to connect to the dev machine from the test
machine, I get the following error.

(gdb) set remotebaud 9600
(gdb) target remote /dev/ttyS1
Remote debugging using /dev/ttyS1
^^
^^^^Ignoring packet error, continuing...
^^^Ignoring packet error, continuing...
Ignoring packet error, continuing...
Ignoring packet error, continuing...
Couldn't establish connection to remote target
Malformed response to offset query, timeout
(gdb)

I've tried other baudrates, but get the same error with them.
Any pointers to where I can get info to get kgdb working for this cross arch
debugging will be helpful.. So far I've searched the web without much luck
on this topic.

Thanks
-Tameen


** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

Re: Kgdb on Motorola 8451 ppc board

[Yuri Frolov]

 > I'm trying to run kgdb on  Motorola 8451 ppc board.
 > I've compiled the kernel with the CONFIG_KGDB option.
 > The test machine is a linux host.

Which platform does your linux host runs on?

 > Ignoring packet error, continuing...
 > Ignoring packet error, continuing...

What sort of gdb are you using on your linux host? Is it a version which
compiled for correct target (ppc with correct endian in your case, see
Net for further explanation)? If you're using vanilla gdb from your's
x86 distribution package (which compiled with source = target = x86),
then you should move to correctly prepared gdb...


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Re: Kgdb on Motorola 8451 ppc board

[Yuri Frolov]

 > I'm trying to run kgdb on  Motorola 8451 ppc board.
 > I've compiled the kernel with the CONFIG_KGDB option.
 > The test machine is a linux host.

Which platform does your linux host runs on?

 > Ignoring packet error, continuing...
 > Ignoring packet error, continuing...

What sort of gdb are you using on your linux host? Is it a version which
compiled for correct target (ppc with correct endian in your case, see
Net for further explanation)? If you're using vanilla gdb from your's
x86 distribution package (which compiled with source = target = x86),
then you should move to correctly prepared gdb...


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RE: Kgdb on Motorola 8451 ppc board

[Swarthout Ed-RA8734]

Tameen asked:

> Any pointers to where I can get info to get kgdb working for this cross
> arch debugging will be helpful..

Three things to look at:

1. You can tell gdb to show everything going over the serial port with:

(gdb) set debug remote 1

but I get similar messages when nothing is even attached to the serial port.

2. Are you seeing "kgdb init" in the console logs?
That message should come from kgdb_map_scc() in gen550_kgdb.c
What serial port are you using for kgdb?

3. Is the gdb stub actually in a position to do a serial port read?  It will only be listening as a result of a trap or if "gdb" is passed on the kernel cmdline.  (See setup_arch() in setup.c)

Disclaimer: I haven't actually tried kgdb on this board and I'm on vacation for two weeks...

Ed dot Swarthout at Freescale dot com


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