KGDBOC testing on linux-2.6.30-rc4

[Bruce Ashfield]

On Mon, May 4, 2009 at 9:13 AM, srikanth krishnakar
<skrishnakar at gmail.com> wrote:
>
>
> Hi all,
>
> I need help in kgdboc  testing on PowerPC target.

Have you tried contacting the maintainer ? (I noticed that Jason
wasn't cc'd), just in case it isn't simply a use case problem and
might be related to KGDB internals.

KGDB
P:      Jason Wessel
M:      jason.wessel at windriver.com

I've tested KGDBOC up to the 2.6.29 kernel and it worked fine
on a series of 85xx boards. I haven't had a chance on 2.6.30-rcX
yet, so something may have changed.

>
> Linux Kernel: 2.6.30-rc4
> KGDB method : KGDBOC
> Arch: PowerPC
>
> Note: Attached is the kernel config  used.
>
> Has anyone tested KGDBOC for Serial 8250, and the serial port has dependency
> on OF_PLATFORM driver ?
>
> Here are the kernel config options:
>
> Device Drivers  --->
>            Character devices  --->
>                           Serial drivers  --->
>                                                      <*> 8250/16550 and
> compatible serial support
>                                                      [*]   Console on
> 8250/16550 and compatible serial port
>                                                      (4) Number of
> 8250/16550 serial ports to register at runtime
>                                                      [ ] Extended 8250/16550
> serial driver options
>                                                      *** Non-8250 serial
> port support ***
>                                                      <*> Xilinx uartlite
> serial port support
>                                                      [*]   Support for
> console on Xilinx uartlite serial port
>                                                      < > Digi International
> NEO PCI Support
>                                                      <*> Serial port on Open
> Firmware platform bus
>                                                      < > NWP serial port
> driver
>
> Kernel hacking  --->
>            -*- Magic SysRq key
>                             [*] Kernel debugging
>                             [*] KGDB: kernel debugging with remote gdb  --->
>                             --- KGDB: kernel debugging with remote
> gdb
>                            <*> KGDB: use kgdb over the serial console
>
>
> ----------------------------------------------
> In the process :
>
>     On the target side :
>
>                              ...............
>                              Serial: 8250/16550 driver, 4 ports, IRQ sharing
> disabled
>                              83e00000.serial: ttyS0 at MMIO 0x83e01003 (irq
> = 16) is a
> 16550A
>                              console [ttyS0]
> enabled
>                              kgdb: Registered I/O driver kgdboc.
>                              .................
>
>                             root at 10.161.2.35:~# echo g > /proc/sysrq-trigger
>                             SysRq : GDB
>                             Entering KGDB
>
>
>   On host side :
>
>                            [root at srikant linux-2.6]# powerpc-linux-gnu-gdb
> vmlinux-puru
>                            GNU gdb G++ 4.3-150) 6.8.50.20081022-cvs
>                            Copyright (C) 2008 Free Software Foundation, Inc.
>                            License GPLv3+: GNU GPL version 3 or later
> <http://gnu.org/licenses/gpl.html>
>                            This is free software: you are free to change and
> redistribute it.
>                            There is NO WARRANTY, to the extent permitted by
> law.  Type "show copying"
>                            and "show warranty" for details.
>                            This GDB was configured as
> "--host=i686-pc-linux-gnu --target=powerpc-linux-gnu".
>                            For bug reporting instructions, please see:
>                           (gdb) set remotebaud 9600
>                           (gdb) target remote /dev/ttyS0
>                            Remote debugging using /dev/ttyS0
>                           Ignoring packet error, continuing...
>                           warning: unrecognized item "timeout" in
> "qSupported" response
>                           Ignoring packet error, continuing...
>                           Ignoring packet error, continuing...
>                           Ignoring packet error, continuing...
>                           Ignoring packet error, continuing...
>                           Ignoring packet error, continuing...
>                           Malformed response to offset query, timeout

I'm wondering if there is a GDB protocol mismatch and your
version of GDB is sending packets that KGDB can't handle.
I'm no where near an expert on GDB's protocol and won't know
if I'm seeing the same thing until I try 2.6.30-rc

Bruce

>
> Can anybody comment on the steps followed in the process of testing or
> something is missing with respect to of_serial.c for powerpc architecture.
> Seems the target has never responded for gdb requests !!!
>
>
> Regards
> Srikanth
>
>
>
>
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> Linuxppc-dev at ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>



-- 
"Thou shalt not follow the NULL pointer, for chaos and madness await
thee at its end"