From be9f56cc9b5120723a57a2f77cb75c8a0fdcb39a Mon Sep 17 00:00:00 2001
From: Ciro Santilli <ciro.santilli@gmail.com>
Date: Sun, 21 May 2017 10:22:31 +0100
Subject: [PATCH] Use buildroot host gdb, consider QEMU and target GDB but give
 up for now

---
 buildroot_config_fragment | 31 +++++++++++++++++++++++++++++++
 run                       |  2 ++
 rungdb                    |  3 ++-
 runqemu                   |  2 ++
 4 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/buildroot_config_fragment b/buildroot_config_fragment
index 8065508..f1652a7 100644
--- a/buildroot_config_fragment
+++ b/buildroot_config_fragment
@@ -1,4 +1,35 @@
 BR2_LINUX_KERNEL_CONFIG_FRAGMENT_FILES="../kernel_config_fragment"
 BR2_PACKAGE_BUSYBOX_CONFIG_FRAGMENT_FILES="../busybox_config_fragment"
 BR2_PACKAGE_KERNEL_MODULE=y
+BR2_PACKAGE_STRACE=y
 BR2_ROOTFS_OVERLAY="../rootfs_overlay"
+
+## Host GDB
+BR2_GDB_VERSION="7.11.1"
+BR2_GDB_VERSION_7_10=n
+BR2_GDB_VERSION_7_11=y
+BR2_GDB_VERSION_7_12=n
+BR2_PACKAGE_HOST_GDB=y
+BR2_PACKAGE_HOST_GDB_PYTHON=y
+BR2_PACKAGE_HOST_GDB_SIM=y
+BR2_PACKAGE_HOST_GDB_TUI=y
+
+## QEMU.
+# Buildroot can also build QEMU, but it does not have SDL support,
+# so you have to mess around with a VNC, so let's not use that for now.
+# Someone should patch this, and add a SDL support option to the QEMU package! :-)
+#BR2_PACKAGE_HOST_QEMU=y
+#BR2_PACKAGE_HOST_QEMU_LINUX_USER_MODE=n
+#BR2_PACKAGE_HOST_QEMU_SYSTEM_MODE=y
+#BR2_PACKAGE_HOST_QEMU_VDE2=y
+
+## Target GDB
+# This is preparation for target GDB / gdbserver.
+# But those options require a toolchain with threads like glibc,
+# which I'm afraid will make compilation slower, so let's leave it
+# at that for now since our focus is kernel debug.
+#BR2_DEBUG_1=n
+#BR2_DEBUG_2=n
+#BR2_DEBUG_3=y
+#BR2_ENABLE_DEBUG=y
+#BR2_OPTIMIZE_0=y
diff --git a/run b/run
index 8161f3f..6ed3844 100755
--- a/run
+++ b/run
@@ -2,6 +2,8 @@
 set -e
 cd buildroot
 make BR2_EXTERNAL="$(pwd)/../kernel_module" qemu_x86_64_defconfig
+# Can't get rid of this for now.
+# http://stackoverflow.com/questions/44078245/is-it-possible-to-use-config-fragments-with-buildroots-config
 cat ../buildroot_config_fragment >> .config
 env -u LD_LIBRARY_PATH make BR2_JLEVEL="$(($(nproc) - 2))" kernel_module-rebuild all
 cd ..
diff --git a/rungdb b/rungdb
index 763e4e6..71b8690 100755
--- a/rungdb
+++ b/rungdb
@@ -4,8 +4,9 @@ if [ "$#" -gt 0 ]; then
 else
   brk=""
 fi
+gdb="$(pwd)/buildroot/output/host/usr/bin/x86_64-linux-gdb"
 cd buildroot/output/build/linux-*.*.*/
-cmd="gdb \
+cmd="$gdb \
   -q \
   -ex 'add-auto-load-safe-path $(pwd)' \
   -ex 'file vmlinux' \
diff --git a/runqemu b/runqemu
index 9afdd44..7606a9b 100755
--- a/runqemu
+++ b/runqemu
@@ -21,6 +21,8 @@ while getopts dn OPT; do
   esac
 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 \
   -append 'root=/dev/vda $extra_append' \