Mini-HOWTO on gdbserver for uCLinux on MMU-less boards

Background

I tried uCLinux distro made 8/8/2008 on an ARM7 MMU-less board and immediately realized that by default gdbserver won't work and probably won't work any MMU-less board supported by uCLinux.

Further it becomes obvious the information about enabling it is also scattered around. I decided to write up what I have found out and what I have done to enable it on my ARM board.

Steps

• uCLinux-distro-200080808 comes with gdb 6.8. Apply this patch to compute offsets.
• Build arm-linux-gdb. See the build script in end of this page.
• Modify your kernel with this patch to fetch vairous addresses related to a process in a MMU-less system. This patch is for 2.6.x kernel.

Build cross gdb

I use a script to build gdb and all other toolchains. Here is the excerpt for the gdb part.

GDB=gdb-6.8

rm -rf build/$GDB
tar xjf download/$GDB.tar.bz2 -C build || exit
cd build/$GDB

mkdir arm-linux
cd arm-linux

../configure --target=arm-linux \
        --prefix=$PREFIX \
        --with-float=soft \
        --disable-multilib \
        --with-gnu-as --with-gnu-ld \
        > $LOGDIR/gdb-configure.txt 2>&1 || exit

make > $LOGDIR/gdb-make.txt 2>&1 || exit

sudo make install > $LOGDIR/gdb-install.txt 2>&1 || exit