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 #include <linux/uaccess.h> 13 #include <asm/sections.h> 14 15 const int rodata_test_data = 0xC3; 16 EXPORT_SYMBOL_GPL(rodata_test_data); 17 18 void rodata_test(void) 19 { 20 unsigned long start, end; 21 int zero = 0; 22 23 /* test 1: read the value */ 24 /* If this test fails, some previous testrun has clobbered the state */ 25 if (!rodata_test_data) { 26 pr_err("rodata_test: test 1 fails (start data)\n"); 27 return; 28 } 29 30 /* test 2: write to the variable; this should fault */ 31 if (!probe_kernel_write((void *)&rodata_test_data, 32 (void *)&zero, sizeof(zero))) { 33 pr_err("rodata_test: test data was not read only\n"); 34 return; 35 } 36 37 /* test 3: check the value hasn't changed */ 38 if (rodata_test_data == zero) { 39 pr_err("rodata_test: test data was changed\n"); 40 return; 41 } 42 43 /* test 4: check if the rodata section is PAGE_SIZE aligned */ 44 start = (unsigned long)__start_rodata; 45 end = (unsigned long)__end_rodata; 46 if (start & (PAGE_SIZE - 1)) { 47 pr_err("rodata_test: start of .rodata is not page size aligned\n"); 48 return; 49 } 50 if (end & (PAGE_SIZE - 1)) { 51 pr_err("rodata_test: end of .rodata is not page size aligned\n"); 52 return; 53 } 54 55 pr_info("rodata_test: all tests were successful\n"); 56 } 57