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}

 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
15static const int rodata_test_data = 0xC3;
16
17void 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}