From 338756a029e1af459387525cb326fc719cb846fe Mon Sep 17 00:00:00 2001
From: Ciro Santilli <ciro.santilli@gmail.com>
Date: Tue, 9 May 2017 19:59:56 +0100
Subject: [PATCH] bak

---
 .gitmodules   |  3 +++
 Config.in     |  6 ++++++
 Makefile      | 10 ++++++++++
 README.md     |  6 +++---
 buildroot     |  1 +
 external.desc |  1 +
 external.mk   | 20 ++++++++++++++++++++
 hello.c       | 13 +++++++++++++
 run           | 10 ++++++++++
 9 files changed, 67 insertions(+), 3 deletions(-)
 create mode 100644 .gitmodules
 create mode 100644 Config.in
 create mode 100644 Makefile
 create mode 160000 buildroot
 create mode 100644 external.desc
 create mode 100644 external.mk
 create mode 100644 hello.c
 create mode 100755 run

diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..b9ab2a0
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "buildroot"]
+	path = buildroot
+	url = https://github.com/buildroot/buildroot
diff --git a/Config.in b/Config.in
new file mode 100644
index 0000000..9a757c5
--- /dev/null
+++ b/Config.in
@@ -0,0 +1,6 @@
+config BR2_PACKAGE_KERNEL_MODULE
+	bool "kernel_module"
+	help
+	  Kernel module hello world.
+
+	  http://example.com/
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..fd934d1
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,10 @@
+obj-m += hello.o
+ccflags-y := -Wno-declaration-after-statement -std=gnu99
+
+.PHONY: all clean
+
+all:
+	$(MAKE) -C '$(LINUX_DIR)' M='$(PWD)' modules
+
+clean:
+	$(MAKE) -C '$(LINUX_DIR)' M='$(PWD)' clean
diff --git a/README.md b/README.md
index 9155383..7d3974c 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,6 @@
 1.  [Build](build.md)
 1.  [kmod](kmod.md)
 1.  Examples
-    1. [Host](host/)
-
-TODO: use Buildroot as in this answer http://stackoverflow.com/a/38813400/895245 to install and test modules on QEMU.
+    1.  [Host](host/)
+    1.  Buildroot
+        1. [hello](hello.c)
diff --git a/buildroot b/buildroot
new file mode 160000
index 0000000..083c073
--- /dev/null
+++ b/buildroot
@@ -0,0 +1 @@
+Subproject commit 083c0735e924e0d534328095a944ae159f661219
diff --git a/external.desc b/external.desc
new file mode 100644
index 0000000..74da067
--- /dev/null
+++ b/external.desc
@@ -0,0 +1 @@
+name: KERNEL_MODULE
diff --git a/external.mk b/external.mk
new file mode 100644
index 0000000..843df5c
--- /dev/null
+++ b/external.mk
@@ -0,0 +1,20 @@
+################################################################################
+#
+# kernel_module
+#
+################################################################################
+
+KERNEL_MODULE_VERSION = 1.0
+KERNEL_MODULE_SITE = ..
+KERNEL_MODULE_SITE_METHOD = local
+
+define KERNEL_MODULE_BUILD_CMDS
+	$(MAKE) -C '$(@D)' LINUX_DIR='$(LINUX_DIR)' PWD='$(@D)' CC='$(TARGET_CC)' LD='$(TARGET_LD)'
+endef
+
+define KERNEL_MODULE_INSTALL_TARGET_CMDS
+	$(INSTALL) -D -m 0755 '$(@D)/kernel_module.ko' '$(TARGET_DIR)/kernel_module.ko'
+endef
+
+$(eval $(kernel-module))
+$(eval $(generic-package))
diff --git a/hello.c b/hello.c
new file mode 100644
index 0000000..0156ed1
--- /dev/null
+++ b/hello.c
@@ -0,0 +1,13 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+
+int init_module(void)
+{
+	printk(KERN_INFO "hello init\n");
+	return 0;
+}
+
+void cleanup_module(void)
+{
+	printk(KERN_INFO "hello cleanup\n");
+}
diff --git a/run b/run
new file mode 100755
index 0000000..c492369
--- /dev/null
+++ b/run
@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -e
+cd buildroot
+make BR2_EXTERNAL="$(pwd)/.." qemu_x86_64_defconfig
+echo '
+BR2_TOOLCHAIN_EXTERNAL=y
+BR2_PACKAGE_KERNEL_MODULE=y
+' >> .config
+make BR2_JLEVEL="$(($(nproc) - 2))"
+qemu-system-x86_64 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2,if=virtio,format=raw -append root=/dev/vda -net nic,model=virtio -net user