1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * This is for all the tests relating directly to Control Flow Integrity.
 4 */
 5#include "lkdtm.h"
 6
 7static int called_count;
 8
 9/* Function taking one argument, without a return value. */
10static noinline void lkdtm_increment_void(int *counter)
11{
12	(*counter)++;
13}
14
15/* Function taking one argument, returning int. */
16static noinline int lkdtm_increment_int(int *counter)
17{
18	(*counter)++;
19
20	return *counter;
21}
22/*
23 * This tries to call an indirect function with a mismatched prototype.
24 */
25void lkdtm_CFI_FORWARD_PROTO(void)
26{
27	/*
28	 * Matches lkdtm_increment_void()'s prototype, but not
29	 * lkdtm_increment_int()'s prototype.
30	 */
31	void (*func)(int *);
32
33	pr_info("Calling matched prototype ...\n");
34	func = lkdtm_increment_void;
35	func(&called_count);
36
37	pr_info("Calling mismatched prototype ...\n");
38	func = (void *)lkdtm_increment_int;
39	func(&called_count);
40
41	pr_err("FAIL: survived mismatched prototype function call!\n");
42	pr_expected_config(CONFIG_CFI_CLANG);
43}