1 files changed, 56 insertions, 0 deletions

diff --git a/mm/rodata_test.c b/mm/rodata_test.c
new file mode 100644
index 000000000000..0fd21670b513
--- /dev/null
+++ b/mm/rodata_test.c
@@ -0,0 +1,56 @@
+/*
+ * rodata_test.c: functional test for mark_rodata_ro function
+ *
+ * (C) Copyright 2008 Intel Corporation
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ */
+#include <linux/uaccess.h>
+#include <asm/sections.h>
+
+const int rodata_test_data = 0xC3;
+EXPORT_SYMBOL_GPL(rodata_test_data);
+
+void rodata_test(void)
+{
+        unsigned long start, end;
+        int zero = 0;
+
+        /* test 1: read the value */
+        /* If this test fails, some previous testrun has clobbered the state */
+        if (!rodata_test_data) {
+                pr_err("rodata_test: test 1 fails (start data)\n");
+                return;
+        }
+
+        /* test 2: write to the variable; this should fault */
+        if (!probe_kernel_write((void *)&rodata_test_data,
+                                                (void *)&zero, sizeof(zero))) {
+                pr_err("rodata_test: test data was not read only\n");
+                return;
+        }
+
+        /* test 3: check the value hasn't changed */
+        if (rodata_test_data == zero) {
+                pr_err("rodata_test: test data was changed\n");
+                return;
+        }
+
+        /* test 4: check if the rodata section is PAGE_SIZE aligned */
+        start = (unsigned long)__start_rodata;
+        end = (unsigned long)__end_rodata;
+        if (start & (PAGE_SIZE - 1)) {
+                pr_err("rodata_test: start of .rodata is not page size aligned\n");
+                return;
+        }
+        if (end & (PAGE_SIZE - 1)) {
+                pr_err("rodata_test: end of .rodata is not page size aligned\n");
+                return;
+        }
+
+        pr_info("rodata_test: all tests were successful\n");
+}