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 17 const int rodata_test_data = 0xC3; 18 19 void 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 } 58