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/uaccess.h> 11 #include <asm/sections.h> 12 13 static const int rodata_test_data = 0xC3; 14 rodata_test(void)15void rodata_test(void) 16 { 17 unsigned long start, end; 18 int zero = 0; 19 20 /* test 1: read the value */ 21 /* If this test fails, some previous testrun has clobbered the state */ 22 if (!rodata_test_data) { 23 pr_err("test 1 fails (start data)\n"); 24 return; 25 } 26 27 /* test 2: write to the variable; this should fault */ 28 if (!probe_kernel_write((void *)&rodata_test_data, 29 (void *)&zero, sizeof(zero))) { 30 pr_err("test data was not read only\n"); 31 return; 32 } 33 34 /* test 3: check the value hasn't changed */ 35 if (rodata_test_data == zero) { 36 pr_err("test data was changed\n"); 37 return; 38 } 39 40 /* test 4: check if the rodata section is PAGE_SIZE aligned */ 41 start = (unsigned long)__start_rodata; 42 end = (unsigned long)__end_rodata; 43 if (start & (PAGE_SIZE - 1)) { 44 pr_err("start of .rodata is not page size aligned\n"); 45 return; 46 } 47 if (end & (PAGE_SIZE - 1)) { 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