1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * rodata_test.c: functional test for mark_rodata_ro function
4 *
5 * (C) Copyright 2008 Intel Corporation
6 * Author: Arjan van de Ven <arjan@linux.intel.com>
7 */
8 #define pr_fmt(fmt) "rodata_test: " fmt
9
10 #include <linux/rodata_test.h>
11 #include <linux/uaccess.h>
12 #include <linux/mm.h>
13 #include <asm/sections.h>
14
15 static const int rodata_test_data = 0xC3;
16
17 void rodata_test(void)
18 {
19 int zero = 0;
20
21 /* test 1: read the value */
22 /* If this test fails, some previous testrun has clobbered the state */
23 if (!rodata_test_data) {
24 pr_err("test 1 fails (start data)\n");
25 return;
26 }
27
28 /* test 2: write to the variable; this should fault */
29 if (!copy_to_kernel_nofault((void *)&rodata_test_data,
30 (void *)&zero, sizeof(zero))) {
31 pr_err("test data was not read only\n");
32 return;
33 }
34
35 /* test 3: check the value hasn't changed */
36 if (rodata_test_data == zero) {
37 pr_err("test data was changed\n");
38 return;
39 }
40
41 /* test 4: check if the rodata section is PAGE_SIZE aligned */
42 if (!PAGE_ALIGNED(__start_rodata)) {
43 pr_err("start of .rodata is not page size aligned\n");
44 return;
45 }
46 if (!PAGE_ALIGNED(__end_rodata)) {
47 pr_err("end of .rodata is not page size aligned\n");
48 return;
49 }
50
51 pr_info("all tests were successful\n");
52 }
53
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