now this works

run

@@ -2,7 +2,8 @@
 set -e
 cd buildroot
 #make BR2_EXTERNAL="$(pwd)/../kernel_module" qemu_x86_64_defconfig
-make BR2_EXTERNAL="$(pwd)/../kernel_module" qemu_arm_vexpress_defconfig
+#make BR2_EXTERNAL="$(pwd)/../kernel_module" qemu_arm_vexpress_defconfig
+make BR2_EXTERNAL="$(pwd)/../kernel_module" qemu_arm_versatile_defconfig
 # Can't get rid of this for now.
 # http://stackoverflow.com/questions/44078245/is-it-possible-to-use-config-fragments-with-buildroots-config
 cat ../buildroot_config_fragment >> .config

rungdb

@@ -4,19 +4,14 @@ if [ "$#" -gt 0 ]; then
 else
   brk=""
 fi
-gdb="$(pwd)/buildroot/output/host/usr/bin/x86_64-linux-gdb"
+gdb="$(pwd)/buildroot/output/host/usr/bin/arm-linux-gdb"
 cd buildroot/output/build/linux-*.*.*/
 cmd="$gdb \
   -q \
   -ex 'add-auto-load-safe-path $(pwd)' \
   -ex 'file vmlinux' \
-  -ex 'set arch i386:x86-64:intel' \
-  -ex 'target remote localhost:1234' \
-  $brk \
-  -ex 'continue' \
-  -ex 'disconnect' \
-  -ex 'set arch i386:x86-64' \
   -ex 'target remote localhost:1234' \
   -ex 'lx-symbols ../kernel_module-1.0/'
 "
+#-ex 'set arch i386:x86-64:intel' \
 eval "$cmd"

runqemu

@@ -23,12 +23,9 @@ done
 
 # If we turn on buildroot host QEMU some day.
 #cmd="./buildroot/output/host/usr/bin/qemu-system-x86_64 \
-#cmd="qemu-system-x86_64 \
-#-M pc \
-#-net nic,model=virtio \
-#-kernel buildroot/output/images/bzImage \
 #cmd="qemu-system-arm \
-  #-M vexpress-a9 \
+#cmd="qemu-system-x86_64 \
+  #-M pc \
   #-append 'root=/dev/vda $extra_append' \
   #-drive file=buildroot/output/images/rootfs.ext2,if=virtio,format=raw \
   #-kernel buildroot/output/images/zImage \
@@ -36,20 +33,16 @@ done
   #-net user \
   #-smp 1 \
   #$extra_flags \
+  #-M pc \
+  #-net nic,model=virtio \
+  #-kernel buildroot/output/images/bzImage \
 #;
 #"
 
-# TODO window opens, but hangs.
-qemu-system-arm \
-  -M vexpress-a9 \
-  -kernel buildroot/output/images/zImage \
-  -dtb buildroot/output/images/vexpress-v2p-ca9.dtb \
-  -drive file=buildroot/output/images/rootfs.ext2,if=scsi,format=raw \
-  -append "root=/dev/sda console=ttyAMA0,115200" \
-  -serial stdio \
-;
-#-net nic,model=rtl8139 \
-#-net user \
+
+cmd='qemu-system-arm -M versatilepb -kernel buildroot/output/images/zImage -dtb buildroot/output/images/versatile-pb.dtb -drive file=buildroot/output/images/rootfs.ext2,if=scsi,format=raw -append "root=/dev/sda console=ttyAMA0,115200" -serial stdio -net nic,model=rtl8139 -net user -nographic'
+#cmd='/data/git/buildroot/output/host/usr/bin/qemu-system-arm -M vexpress-a9 -smp 1 -m 256 -kernel buildroot/output/images/zImage -dtb buildroot/output/images/vexpress-v2p-ca9.dtb -drive file=buildroot/output/images/rootfs.ext2,if=sd,format=raw -append "console=ttyAMA0,115200 root=/dev/mmcblk0" -serial stdio -net nic,model=lan9118 -net user'
+#cmd='qemu-system-arm -M vexpress-a9 -smp 1 -m 256 -kernel buildroot/output/images/zImage -dtb buildroot/output/images/vexpress-v2p-ca9.dtb -drive file=buildroot/output/images/rootfs.ext2,if=sd,format=raw -append "console=ttyAMA0,115200 root=/dev/mmcblk0" -serial stdio -net nic,model=lan9118 -net user'
 
 if $debug && ! $nographic; then
   eval nohup "$cmd" &>/dev/null &