1/*
2 * rodata_test.c: functional test for mark_rodata_ro function
3 *
4 * (C) Copyright 2008 Intel Corporation
5 * Author: Arjan van de Ven <arjan@linux.intel.com>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; version 2
10 * of the License.
11 */
12#define pr_fmt(fmt) "rodata_test: " fmt
13
14#include <linux/uaccess.h>
15#include <asm/sections.h>
16
17static const int rodata_test_data = 0xC3;
18
19void rodata_test(void)
20{
21 unsigned long start, end;
22 int zero = 0;
23
24 /* test 1: read the value */
25 /* If this test fails, some previous testrun has clobbered the state */
26 if (!rodata_test_data) {
27 pr_err("test 1 fails (start data)\n");
28 return;
29 }
30
31 /* test 2: write to the variable; this should fault */
32 if (!probe_kernel_write((void *)&rodata_test_data,
33 (void *)&zero, sizeof(zero))) {
34 pr_err("test data was not read only\n");
35 return;
36 }
37
38 /* test 3: check the value hasn't changed */
39 if (rodata_test_data == zero) {
40 pr_err("test data was changed\n");
41 return;
42 }
43
44 /* test 4: check if the rodata section is PAGE_SIZE aligned */
45 start = (unsigned long)__start_rodata;
46 end = (unsigned long)__end_rodata;
47 if (start & (PAGE_SIZE - 1)) {
48 pr_err("start of .rodata is not page size aligned\n");
49 return;
50 }
51 if (end & (PAGE_SIZE - 1)) {
52 pr_err("end of .rodata is not page size aligned\n");
53 return;
54 }
55
56 pr_info("all tests were successful\n");
57}
58