1 files changed, 53 insertions, 0 deletions
diff --git a/mm/rodata_test.c b/mm/rodata_test.c
new file mode 100644
index 000000000000..e7173fcd210c
--- /dev/null
+++ b/mm/rodata_test.c
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * rodata_test.c: functional test for mark_rodata_ro function
+ *
+ * (C) Copyright 2008 Intel Corporation
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ */
+#define pr_fmt(fmt) "rodata_test: " fmt
+
+#include <linux/rodata_test.h>
+#include <linux/uaccess.h>
+#include <linux/mm.h>
+#include <asm/sections.h>
+
+#define TEST_VALUE 0xC3
+static const int rodata_test_data = TEST_VALUE;
+
+void rodata_test(void)
+{
+	int zero = 0;
+
+	/* test 1: read the value */
+	/* If this test fails, some previous testrun has clobbered the state */
+	if (unlikely(READ_ONCE(rodata_test_data) != TEST_VALUE)) {
+		pr_err("test 1 fails (start data)\n");
+		return;
+	}
+
+	/* test 2: write to the variable; this should fault */
+	if (!copy_to_kernel_nofault((void *)&rodata_test_data,
+				(void *)&zero, sizeof(zero))) {
+		pr_err("test data was not read only\n");
+		return;
+	}
+
+	/* test 3: check the value hasn't changed */
+	if (unlikely(READ_ONCE(rodata_test_data) != TEST_VALUE)) {
+		pr_err("test data was changed\n");
+		return;
+	}
+
+	/* test 4: check if the rodata section is PAGE_SIZE aligned */
+	if (!PAGE_ALIGNED(__start_rodata)) {
+		pr_err("start of .rodata is not page size aligned\n");
+		return;
+	}
+	if (!PAGE_ALIGNED(__end_rodata)) {
+		pr_err("end of .rodata is not page size aligned\n");
+		return;
+	}
+
+	pr_info("all tests were successful\n");
+}