1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2022 ARM Limited.
4  * Original author: Mark Brown <broonie@kernel.org>
5  */
6 
7 // SPDX-License-Identifier: GPL-2.0-only
8 
9 #include <linux/sched.h>
10 #include <linux/wait.h>
11 
12 #include "kselftest.h"
13 
14 #define EXPECTED_TESTS 1
15 
16 int fork_test(void);
17 int verify_fork(void);
18 
19 /*
20  * If we fork the value in the parent should be unchanged and the
21  * child should start with the same value.  This is called from the
22  * fork_test() asm function.
23  */
24 int fork_test_c(void)
25 {
26 	pid_t newpid, waiting;
27 	int child_status, parent_result;
28 
29 	newpid = fork();
30 	if (newpid == 0) {
31 		/* In child */
32 		if (!verify_fork()) {
33 			ksft_print_msg("ZA state invalid in child\n");
34 			exit(0);
35 		} else {
36 			exit(1);
37 		}
38 	}
39 	if (newpid < 0) {
40 		ksft_print_msg("fork() failed: %d\n", newpid);
41 
42 		return 0;
43 	}
44 
45 	parent_result = verify_fork();
46 	if (!parent_result)
47 		ksft_print_msg("ZA state invalid in parent\n");
48 
49 	for (;;) {
50 		waiting = waitpid(newpid, &child_status, 0);
51 
52 		if (waiting < 0) {
53 			if (errno == EINTR)
54 				continue;
55 			ksft_print_msg("waitpid() failed: %d\n", errno);
56 			return 0;
57 		}
58 		if (waiting != newpid) {
59 			ksft_print_msg("waitpid() returned wrong PID\n");
60 			return 0;
61 		}
62 
63 		if (!WIFEXITED(child_status)) {
64 			ksft_print_msg("child did not exit\n");
65 			return 0;
66 		}
67 
68 		return WEXITSTATUS(child_status) && parent_result;
69 	}
70 }
71 
72 int main(int argc, char **argv)
73 {
74 	int ret, i;
75 
76 	ksft_print_header();
77 	ksft_set_plan(EXPECTED_TESTS);
78 
79 	ksft_print_msg("PID: %d\n", getpid());
80 
81 	/*
82 	 * This test is run with nolibc which doesn't support hwcap and
83 	 * it's probably disproportionate to implement so instead check
84 	 * for the default vector length configuration in /proc.
85 	 */
86 	ret = open("/proc/sys/abi/sme_default_vector_length", O_RDONLY, 0);
87 	if (ret >= 0) {
88 		ksft_test_result(fork_test(), "fork_test\n");
89 
90 	} else {
91 		ksft_print_msg("SME not supported\n");
92 		for (i = 0; i < EXPECTED_TESTS; i++) {
93 			ksft_test_result_skip("fork_test\n");
94 		}
95 	}
96 
97 	ksft_finished();
98 
99 	return 0;
100 }
101