2 * test_rodata.c: functional test for mark_rodata_ro function
4 * (C) Copyright 2008 Intel Corporation
5 * Author: Arjan van de Ven <arjan@linux.intel.com>
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
12 #include <linux/module.h>
13 #include <asm/cacheflush.h>
14 #include <asm/sections.h>
19 unsigned long start, end;
21 /* test 1: read the value */
22 /* If this test fails, some previous testrun has clobbered the state */
23 if (!rodata_test_data) {
24 printk(KERN_ERR "rodata_test: test 1 fails (start data)\n");
28 /* test 2: write to the variable; this should fault */
30 * If this test fails, we managed to overwrite the data
32 * This is written in assembly to be able to catch the
33 * exception that is supposed to happen in the correct
39 "0: mov %[zero],(%[rodata_test])\n"
40 " mov %[zero], %[rslt]\n"
42 ".section .fixup,\"ax\"\n"
45 ".section __ex_table,\"a\"\n"
53 : [rslt] "=r" (result)
54 : [rodata_test] "r" (&rodata_test_data), [zero] "r" (0UL)
59 printk(KERN_ERR "rodata_test: test data was not read only\n");
63 /* test 3: check the value hasn't changed */
64 /* If this test fails, we managed to overwrite the data */
65 if (!rodata_test_data) {
66 printk(KERN_ERR "rodata_test: Test 3 failes (end data)\n");
69 /* test 4: check if the rodata section is 4Kb aligned */
70 start = (unsigned long)__start_rodata;
71 end = (unsigned long)__end_rodata;
72 if (start & (PAGE_SIZE - 1)) {
73 printk(KERN_ERR "rodata_test: .rodata is not 4k aligned\n");
76 if (end & (PAGE_SIZE - 1)) {
77 printk(KERN_ERR "rodata_test: .rodata end is not 4k aligned\n");
84 MODULE_LICENSE("GPL");
85 MODULE_DESCRIPTION("Testcase for the DEBUG_RODATA infrastructure");
86 MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");