[PATCH v4 2/2] Add selftests for module build using in-kernel headers

["Joel Fernandes (Google)" <joel@joelfernandes.org>]

This test tries to build a module successfully using the in-kernel
headers found in /proc/kheaders.tar.xz.

Verified pass and fail scenarios by running:
make -C tools/testing/selftests TARGETS=kheaders run_tests

Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
---
 tools/testing/selftests/Makefile              |  1 +
 tools/testing/selftests/kheaders/Makefile     |  5 +++++
 tools/testing/selftests/kheaders/config       |  1 +
 .../kheaders/run_kheaders_modbuild.sh         | 18 +++++++++++++++++
 .../selftests/kheaders/testmod/Makefile       |  3 +++
 .../testing/selftests/kheaders/testmod/test.c | 20 +++++++++++++++++++
 6 files changed, 48 insertions(+)
 create mode 100644 tools/testing/selftests/kheaders/Makefile
 create mode 100644 tools/testing/selftests/kheaders/config
 create mode 100755 tools/testing/selftests/kheaders/run_kheaders_modbuild.sh
 create mode 100644 tools/testing/selftests/kheaders/testmod/Makefile
 create mode 100644 tools/testing/selftests/kheaders/testmod/test.c

diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 400ee81a3043..5a9287fddd0d 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -20,6 +20,7 @@ TARGETS += intel_pstate
 TARGETS += ipc
 TARGETS += ir
 TARGETS += kcmp
+TARGETS += kheaders
 TARGETS += kvm
 TARGETS += lib
 TARGETS += membarrier
diff --git a/tools/testing/selftests/kheaders/Makefile b/tools/testing/selftests/kheaders/Makefile
new file mode 100644
index 000000000000..51035ab0732b
--- /dev/null
+++ b/tools/testing/selftests/kheaders/Makefile
@@ -0,0 +1,5 @@
+# SPDX-License-Identifier: GPL-2.0
+
+TEST_PROGS := run_kheaders_modbuild.sh
+
+include ../lib.mk
diff --git a/tools/testing/selftests/kheaders/config b/tools/testing/selftests/kheaders/config
new file mode 100644
index 000000000000..5221f9fb5e79
--- /dev/null
+++ b/tools/testing/selftests/kheaders/config
@@ -0,0 +1 @@
+CONFIG_IKHEADERS_PROC=y
diff --git a/tools/testing/selftests/kheaders/run_kheaders_modbuild.sh b/tools/testing/selftests/kheaders/run_kheaders_modbuild.sh
new file mode 100755
index 000000000000..f001568e08b0
--- /dev/null
+++ b/tools/testing/selftests/kheaders/run_kheaders_modbuild.sh
@@ -0,0 +1,18 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+HEADERS_XZ=/proc/kheaders.tar.xz
+TMP_DIR_HEADERS=$(mktemp -d)
+TMP_DIR_MODULE=$(mktemp -d)
+SPATH="$(dirname "$(readlink -f "$0")")"
+
+tar -xvf $HEADERS_XZ -C $TMP_DIR_HEADERS > /dev/null
+
+cp -r $SPATH/testmod $TMP_DIR_MODULE/
+
+pushd $TMP_DIR_MODULE/testmod > /dev/null
+make -C $TMP_DIR_HEADERS M=$(pwd) modules
+popd > /dev/null
+
+rm -rf $TMP_DIR_HEADERS
+rm -rf $TMP_DIR_MODULE
diff --git a/tools/testing/selftests/kheaders/testmod/Makefile b/tools/testing/selftests/kheaders/testmod/Makefile
new file mode 100644
index 000000000000..7083e28706e8
--- /dev/null
+++ b/tools/testing/selftests/kheaders/testmod/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-m += test.o
diff --git a/tools/testing/selftests/kheaders/testmod/test.c b/tools/testing/selftests/kheaders/testmod/test.c
new file mode 100644
index 000000000000..6eb0b8492ffa
--- /dev/null
+++ b/tools/testing/selftests/kheaders/testmod/test.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+
+static int __init hello_init(void)
+{
+	printk(KERN_INFO "Hello, world\n");
+	return 0;
+}
+
+static void __exit hello_exit(void)
+{
+	printk(KERN_INFO "Goodbye, world\n");
+}
+
+module_init(hello_init);
+module_exit(hello_exit);
+MODULE_LICENSE("GPL v2");
-- 
2.21.0.352.gf09ad66450-goog