/* * test_rodata.c: functional test for mark_rodata_ro function * * (C) Copyright 2008 Intel Corporation * Author: Arjan van de Ven <arjan@linux.intel.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; version 2 * of the License. */#include <linux/module.h>#include <asm/cacheflush.h>#include <asm/sections.h>#include <asm/asm.h> int rodata_test(void){	unsigned long result;	unsigned long start, end; 	/* test 1: read the value */	/* If this test fails, some previous testrun has clobbered the state */	if (!rodata_test_data) {		printk(KERN_ERR "rodata_test: test 1 fails (start data)\n");		return -ENODEV;	} 	/* test 2: write to the variable; this should fault */	/*	 * If this test fails, we managed to overwrite the data	 *	 * This is written in assembly to be able to catch the	 * exception that is supposed to happen in the correct	 * case	 */ 	result = 1;	asm volatile(		"0:	mov %[zero],(%[rodata_test])\n"		"	mov %[zero], %[rslt]\n"		"1:\n"		".section .fixup,\"ax\"\n"		"2:	jmp 1b\n"		".previous\n"		_ASM_EXTABLE(0b,2b)		: [rslt] "=r" (result)		: [rodata_test] "r" (&rodata_test_data), [zero] "r" (0UL)	);  	if (!result) {		printk(KERN_ERR "rodata_test: test data was not read only\n");		return -ENODEV;	} 	/* test 3: check the value hasn't changed */	/* If this test fails, we managed to overwrite the data */	if (!rodata_test_data) {		printk(KERN_ERR "rodata_test: Test 3 failes (end data)\n");		return -ENODEV;	}	/* test 4: check if the rodata section is 4Kb aligned */	start = (unsigned long)__start_rodata;	end = (unsigned long)__end_rodata;	if (start & (PAGE_SIZE - 1)) {		printk(KERN_ERR "rodata_test: .rodata is not 4k aligned\n");		return -ENODEV;	}	if (end & (PAGE_SIZE - 1)) {		printk(KERN_ERR "rodata_test: .rodata end is not 4k aligned\n");		return -ENODEV;	} 	return 0;} MODULE_LICENSE("GPL");MODULE_DESCRIPTION("Testcase for the DEBUG_RODATA infrastructure");MODULE_AUTHOR("Arjan van de Ven <arjan@linux.intel.com>");