projects / mirror_ubuntu-bionic-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| edeed305 AV |
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> | |
| 7bfeab9a | 13 | #include <asm/cacheflush.h> |
| edeed305 | 14 | #include <asm/sections.h> |
| edeed305 AV |
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>"); |