Arjan van de Ven | edeed30 | 2008-01-30 13:34:08 +0100 | [diff] [blame] | 1 | /* |
| 2 | * test_rodata.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 | #include <linux/module.h> |
Harvey Harrison | 7bfeab9 | 2008-02-12 12:12:01 -0800 | [diff] [blame] | 13 | #include <asm/cacheflush.h> |
Arjan van de Ven | edeed30 | 2008-01-30 13:34:08 +0100 | [diff] [blame] | 14 | #include <asm/sections.h> |
Arjan van de Ven | edeed30 | 2008-01-30 13:34:08 +0100 | [diff] [blame] | 15 | |
| 16 | int rodata_test(void) |
| 17 | { |
| 18 | unsigned long result; |
| 19 | unsigned long start, end; |
| 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 | printk(KERN_ERR "rodata_test: test 1 fails (start data)\n"); |
| 25 | return -ENODEV; |
| 26 | } |
| 27 | |
| 28 | /* test 2: write to the variable; this should fault */ |
| 29 | /* |
| 30 | * If this test fails, we managed to overwrite the data |
| 31 | * |
| 32 | * This is written in assembly to be able to catch the |
| 33 | * exception that is supposed to happen in the correct |
| 34 | * case |
| 35 | */ |
| 36 | |
| 37 | result = 1; |
| 38 | asm volatile( |
| 39 | "0: mov %[zero],(%[rodata_test])\n" |
| 40 | " mov %[zero], %[rslt]\n" |
| 41 | "1:\n" |
| 42 | ".section .fixup,\"ax\"\n" |
| 43 | "2: jmp 1b\n" |
| 44 | ".previous\n" |
| 45 | ".section __ex_table,\"a\"\n" |
| 46 | " .align 16\n" |
| 47 | #ifdef CONFIG_X86_32 |
| 48 | " .long 0b,2b\n" |
| 49 | #else |
| 50 | " .quad 0b,2b\n" |
| 51 | #endif |
| 52 | ".previous" |
| 53 | : [rslt] "=r" (result) |
| 54 | : [rodata_test] "r" (&rodata_test_data), [zero] "r" (0UL) |
| 55 | ); |
| 56 | |
| 57 | |
| 58 | if (!result) { |
| 59 | printk(KERN_ERR "rodata_test: test data was not read only\n"); |
| 60 | return -ENODEV; |
| 61 | } |
| 62 | |
| 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"); |
| 67 | return -ENODEV; |
| 68 | } |
| 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"); |
| 74 | return -ENODEV; |
| 75 | } |
| 76 | if (end & (PAGE_SIZE - 1)) { |
| 77 | printk(KERN_ERR "rodata_test: .rodata end is not 4k aligned\n"); |
| 78 | return -ENODEV; |
| 79 | } |
| 80 | |
| 81 | return 0; |
| 82 | } |
| 83 | |
| 84 | MODULE_LICENSE("GPL"); |
| 85 | MODULE_DESCRIPTION("Testcase for the DEBUG_RODATA infrastructure"); |
| 86 | MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>"); |