| 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 | #define TEST_VALUE 0xC3 |
| 16 | static const int rodata_test_data = TEST_VALUE; |
| 17 | |
| 18 | void rodata_test(void) |
| 19 | { |
| 20 | int zero = 0; |
| 21 | |
| 22 | /* test 1: read the value */ |
| 23 | /* If this test fails, some previous testrun has clobbered the state */ |
| 24 | if (unlikely(READ_ONCE(rodata_test_data) != TEST_VALUE)) { |
| 25 | pr_err("test 1 fails (start data)\n"); |
| 26 | return; |
| 27 | } |
| 28 | |
| 29 | /* test 2: write to the variable; this should fault */ |
| 30 | if (!copy_to_kernel_nofault(dst: (void *)&rodata_test_data, |
| 31 | src: (void *)&zero, size: sizeof(zero))) { |
| 32 | pr_err("test data was not read only\n"); |
| 33 | return; |
| 34 | } |
| 35 | |
| 36 | /* test 3: check the value hasn't changed */ |
| 37 | if (unlikely(READ_ONCE(rodata_test_data) != TEST_VALUE)) { |
| 38 | pr_err("test data was changed\n"); |
| 39 | return; |
| 40 | } |
| 41 | |
| 42 | /* test 4: check if the rodata section is PAGE_SIZE aligned */ |
| 43 | if (!PAGE_ALIGNED(__start_rodata)) { |
| 44 | pr_err("start of .rodata is not page size aligned\n"); |
| 45 | return; |
| 46 | } |
| 47 | if (!PAGE_ALIGNED(__end_rodata)) { |
| 48 | pr_err("end of .rodata is not page size aligned\n"); |
| 49 | return; |
| 50 | } |
| 51 | |
| 52 | pr_info("all tests were successful\n"); |
| 53 | } |
| 54 |