Invalid hex digit 59 - Linux MIPS kernel debugging

["Alex Gonzalez" <langabe at gmail dot com>]

Hi,

I am trying to debug the Linux MIPS kernel using gdb.

I have the gdb stub in the kernel and gdb communicating through the
serial interface, I seem to be able to set a breakpoint but gdb never
hits it. It complains with a 'Reply contains invalid hex digit 59',
which  I guess refers to the semicolon character used in the response.

I enclose the session output in case someone can give me some pointers.

Thanks in advance,
Alex

------------------------------------------------------

root@euskadi:/tftpboot/pv-rootfs# bin/i386-linux-gdb
usr/src/repository/linux/vmlinux
GNU gdb 6.3
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or 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.
This GDB was configured as "--host=i686-pc-linux-gnu --target=mips-linux-gnu"...
(gdb) set remotebaud 115200
(gdb) target remote /dev/ttyS0
Remote debugging using /dev/ttyS0
0x3f0000001d in ?? ()
warning: shared library handler failed to enable breakpoint
(gdb) break calibrate_delay
Breakpoint 1 at 0x80323020: file init/calibrate.c, line 32.
(gdb) c
Continuing.
Reply contains invalid hex digit 59
(gdb) q
The program is running.  Exit anyway? (y or n) y
root@euskadi:/tftpboot/pv-rootfs# bin/i386-linux-gdb
usr/src/repository/linux/vmlinux
GNU gdb 6.3
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or 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.
This GDB was configured as "--host=i686-pc-linux-gnu --target=mips-linux-gnu"...
(gdb) set remotebaud 115200
(gdb) set debug remote 1
(gdb) target remote /dev/ttyS0
Remote debugging using /dev/ttyS0
Sending packet: $Hc-1#09...Ack
Packet received: T0525:8010b820;48:d8d1c7bf;1d:802f1f10;
Sending packet: $qC#b4...Ack
Packet received:
Sending packet: $qOffsets#4b...Ack
Packet received:
Sending packet: $?#3f...Ack
Packet received: S05
Sending packet: $Hg0#df...Ack
Packet received:
Sending packet: $p25#d7...Ack
Packet received:
Sending packet: $g#67...Ack
Packet received:
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
Sending packet: $m3c,4#63...Ack
Packet received: E03
Sending packet: $m38,4#38...Ack
Packet received: E03
Sending packet: $m3c,4#63...Ack
Packet received: E03
Sending packet: $m38,4#38...Ack
Packet received: E03
0x3f0000003c in ?? ()
warning: shared library handler failed to enable breakpoint
Sending packet: $qSymbol::#5b...Ack
Packet received:
Packet qSymbol (symbol-lookup) is NOT supported
(gdb) break calibrate_delay
Sending packet: $m80323020,4#5f...Ack
Packet received: 3c028034
Sending packet: $m80323024,4#63...Ack
Packet received: 8c42e570
Sending packet: $m80323028,4#67...Ack
Packet received: 27bdffe8
Breakpoint 1 at 0x80323020: file init/calibrate.c, line 32.
(gdb) c
Continuing.
Sending packet: $Z0,80323020,4#a8...Ack
Packet received:
Packet Z0 (software-breakpoint) is NOT supported
Sending packet: $m80323020,4#5f...Ack
Packet received: 3c028034
Sending packet: $X80323020,0:#80...Ack
Packet received: OK
binary downloading suppported by target
Sending packet: $X80323020,4:\000\005\000\r#96...Ack
Packet received: OK
Sending packet: $vCont?#49...Ack
Packet received:
Packet vCont (verbose-resume) is NOT supported
Sending packet: $Hc0#db...Ack
Packet received:
Sending packet: $c#63...Ack
Packet received: T0525:80323020;48:d8d1c7bf;1d:802f1fa8;
Reply contains invalid hex digit 59
(gdb)