s390/module: test loading modules with a lot of relocations

Add a test in order to prevent regressions.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/Kconfig

@@ -945,6 +945,9 @@ config S390_GUEST
 
 endmenu
 
+config S390_MODULES_SANITY_TEST_HELPERS
+	def_bool n
+
 menu "Selftests"
 
 config S390_UNWIND_SELFTEST
@@ -971,4 +974,16 @@ config S390_KPROBES_SANITY_TEST
 
 	  Say N if you are unsure.
 
+config S390_MODULES_SANITY_TEST
+	def_tristate n
+	depends on KUNIT
+	default KUNIT_ALL_TESTS
+	prompt "Enable s390 specific modules tests"
+	select S390_MODULES_SANITY_TEST_HELPERS
+	help
+	  This option enables an s390 specific modules test. This option is
+	  not useful for distributions or general kernels, but only for
+	  kernel developers working on architecture code.
+
+	  Say N if you are unsure.
 endmenu

arch/s390/lib/Makefile

@@ -17,4 +17,7 @@ KASAN_SANITIZE_uaccess.o := n
 obj-$(CONFIG_S390_UNWIND_SELFTEST) += test_unwind.o
 CFLAGS_test_unwind.o += -fno-optimize-sibling-calls
 
+obj-$(CONFIG_S390_MODULES_SANITY_TEST) += test_modules.o
+obj-$(CONFIG_S390_MODULES_SANITY_TEST_HELPERS) += test_modules_helpers.o
+
 lib-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o

arch/s390/lib/test_modules.c

@@ -0,0 +1,35 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <kunit/test.h>
+#include <linux/module.h>
+
+#include "test_modules.h"
+
+#define DECLARE_RETURN(i) int test_modules_return_ ## i(void)
+REPEAT_10000(DECLARE_RETURN);
+
+/*
+ * Test that modules with many relocations are loaded properly.
+ */
+static void test_modules_many_vmlinux_relocs(struct kunit *test)
+{
+	int result = 0;
+
+#define CALL_RETURN(i) result += test_modules_return_ ## i()
+	REPEAT_10000(CALL_RETURN);
+	KUNIT_ASSERT_EQ(test, result, 49995000);
+}
+
+static struct kunit_case modules_testcases[] = {
+	KUNIT_CASE(test_modules_many_vmlinux_relocs),
+	{}
+};
+
+static struct kunit_suite modules_test_suite = {
+	.name = "modules_test_s390",
+	.test_cases = modules_testcases,
+};
+
+kunit_test_suites(&modules_test_suite);
+
+MODULE_LICENSE("GPL");

arch/s390/lib/test_modules.h

@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef TEST_MODULES_H
+#define TEST_MODULES_H
+
+#define __REPEAT_10000_3(f, x) \
+	f(x ## 0); \
+	f(x ## 1); \
+	f(x ## 2); \
+	f(x ## 3); \
+	f(x ## 4); \
+	f(x ## 5); \
+	f(x ## 6); \
+	f(x ## 7); \
+	f(x ## 8); \
+	f(x ## 9)
+#define __REPEAT_10000_2(f, x) \
+	__REPEAT_10000_3(f, x ## 0); \
+	__REPEAT_10000_3(f, x ## 1); \
+	__REPEAT_10000_3(f, x ## 2); \
+	__REPEAT_10000_3(f, x ## 3); \
+	__REPEAT_10000_3(f, x ## 4); \
+	__REPEAT_10000_3(f, x ## 5); \
+	__REPEAT_10000_3(f, x ## 6); \
+	__REPEAT_10000_3(f, x ## 7); \
+	__REPEAT_10000_3(f, x ## 8); \
+	__REPEAT_10000_3(f, x ## 9)
+#define __REPEAT_10000_1(f, x) \
+	__REPEAT_10000_2(f, x ## 0); \
+	__REPEAT_10000_2(f, x ## 1); \
+	__REPEAT_10000_2(f, x ## 2); \
+	__REPEAT_10000_2(f, x ## 3); \
+	__REPEAT_10000_2(f, x ## 4); \
+	__REPEAT_10000_2(f, x ## 5); \
+	__REPEAT_10000_2(f, x ## 6); \
+	__REPEAT_10000_2(f, x ## 7); \
+	__REPEAT_10000_2(f, x ## 8); \
+	__REPEAT_10000_2(f, x ## 9)
+#define REPEAT_10000(f) \
+	__REPEAT_10000_1(f, 0); \
+	__REPEAT_10000_1(f, 1); \
+	__REPEAT_10000_1(f, 2); \
+	__REPEAT_10000_1(f, 3); \
+	__REPEAT_10000_1(f, 4); \
+	__REPEAT_10000_1(f, 5); \
+	__REPEAT_10000_1(f, 6); \
+	__REPEAT_10000_1(f, 7); \
+	__REPEAT_10000_1(f, 8); \
+	__REPEAT_10000_1(f, 9)
+
+#endif

arch/s390/lib/test_modules_helpers.c

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+#include <linux/export.h>
+
+#include "test_modules.h"
+
+#define DEFINE_RETURN(i) \
+	int test_modules_return_ ## i(void) \
+	{ \
+		return 1 ## i - 10000; \
+	} \
+	EXPORT_SYMBOL_GPL(test_modules_return_ ## i)
+REPEAT_10000(DEFINE_RETURN);