1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include <linux/sched.h>
4 #include <linux/wait.h>
5 
6 #define SYS_TPIDR2 "S3_3_C13_C0_5"
7 
8 #define EXPECTED_TESTS 5
9 
10 static void putstr(const char *str)
11 {
12 	write(1, str, strlen(str));
13 }
14 
15 static void putnum(unsigned int num)
16 {
17 	char c;
18 
19 	if (num / 10)
20 		putnum(num / 10);
21 
22 	c = '0' + (num % 10);
23 	write(1, &c, 1);
24 }
25 
26 static int tests_run;
27 static int tests_passed;
28 static int tests_failed;
29 static int tests_skipped;
30 
31 static void set_tpidr2(uint64_t val)
32 {
33 	asm volatile (
34 		"msr	" SYS_TPIDR2 ", %0\n"
35 		:
36 		: "r"(val)
37 		: "cc");
38 }
39 
40 static uint64_t get_tpidr2(void)
41 {
42 	uint64_t val;
43 
44 	asm volatile (
45 		"mrs	%0, " SYS_TPIDR2 "\n"
46 		: "=r"(val)
47 		:
48 		: "cc");
49 
50 	return val;
51 }
52 
53 static void print_summary(void)
54 {
55 	if (tests_passed + tests_failed + tests_skipped != EXPECTED_TESTS)
56 		putstr("# UNEXPECTED TEST COUNT: ");
57 
58 	putstr("# Totals: pass:");
59 	putnum(tests_passed);
60 	putstr(" fail:");
61 	putnum(tests_failed);
62 	putstr(" xfail:0 xpass:0 skip:");
63 	putnum(tests_skipped);
64 	putstr(" error:0\n");
65 }
66 
67 /* Processes should start with TPIDR2 == 0 */
68 static int default_value(void)
69 {
70 	return get_tpidr2() == 0;
71 }
72 
73 /* If we set TPIDR2 we should read that value */
74 static int write_read(void)
75 {
76 	set_tpidr2(getpid());
77 
78 	return getpid() == get_tpidr2();
79 }
80 
81 /* If we set a value we should read the same value after scheduling out */
82 static int write_sleep_read(void)
83 {
84 	set_tpidr2(getpid());
85 
86 	msleep(100);
87 
88 	return getpid() == get_tpidr2();
89 }
90 
91 /*
92  * If we fork the value in the parent should be unchanged and the
93  * child should start with the same value and be able to set its own
94  * value.
95  */
96 static int write_fork_read(void)
97 {
98 	pid_t newpid, waiting, oldpid;
99 	int status;
100 
101 	set_tpidr2(getpid());
102 
103 	oldpid = getpid();
104 	newpid = fork();
105 	if (newpid == 0) {
106 		/* In child */
107 		if (get_tpidr2() != oldpid) {
108 			putstr("# TPIDR2 changed in child: ");
109 			putnum(get_tpidr2());
110 			putstr("\n");
111 			exit(0);
112 		}
113 
114 		set_tpidr2(getpid());
115 		if (get_tpidr2() == getpid()) {
116 			exit(1);
117 		} else {
118 			putstr("# Failed to set TPIDR2 in child\n");
119 			exit(0);
120 		}
121 	}
122 	if (newpid < 0) {
123 		putstr("# fork() failed: -");
124 		putnum(-newpid);
125 		putstr("\n");
126 		return 0;
127 	}
128 
129 	for (;;) {
130 		waiting = waitpid(newpid, &status, 0);
131 
132 		if (waiting < 0) {
133 			if (errno == EINTR)
134 				continue;
135 			putstr("# waitpid() failed: ");
136 			putnum(errno);
137 			putstr("\n");
138 			return 0;
139 		}
140 		if (waiting != newpid) {
141 			putstr("# waitpid() returned wrong PID\n");
142 			return 0;
143 		}
144 
145 		if (!WIFEXITED(status)) {
146 			putstr("# child did not exit\n");
147 			return 0;
148 		}
149 
150 		if (getpid() != get_tpidr2()) {
151 			putstr("# TPIDR2 corrupted in parent\n");
152 			return 0;
153 		}
154 
155 		return WEXITSTATUS(status);
156 	}
157 }
158 
159 /*
160  * sys_clone() has a lot of per architecture variation so just define
161  * it here rather than adding it to nolibc, plus the raw API is a
162  * little more convenient for this test.
163  */
164 static int sys_clone(unsigned long clone_flags, unsigned long newsp,
165 		     int *parent_tidptr, unsigned long tls,
166 		     int *child_tidptr)
167 {
168 	return my_syscall5(__NR_clone, clone_flags, newsp, parent_tidptr, tls,
169 			   child_tidptr);
170 }
171 
172 /*
173  * If we clone with CLONE_SETTLS then the value in the parent should
174  * be unchanged and the child should start with zero and be able to
175  * set its own value.
176  */
177 static int write_clone_read(void)
178 {
179 	int parent_tid, child_tid;
180 	pid_t parent, waiting;
181 	int ret, status;
182 
183 	parent = getpid();
184 	set_tpidr2(parent);
185 
186 	ret = sys_clone(CLONE_SETTLS, 0, &parent_tid, 0, &child_tid);
187 	if (ret == -1) {
188 		putstr("# clone() failed\n");
189 		putnum(errno);
190 		putstr("\n");
191 		return 0;
192 	}
193 
194 	if (ret == 0) {
195 		/* In child */
196 		if (get_tpidr2() != 0) {
197 			putstr("# TPIDR2 non-zero in child: ");
198 			putnum(get_tpidr2());
199 			putstr("\n");
200 			exit(0);
201 		}
202 
203 		if (gettid() == 0)
204 			putstr("# Child TID==0\n");
205 		set_tpidr2(gettid());
206 		if (get_tpidr2() == gettid()) {
207 			exit(1);
208 		} else {
209 			putstr("# Failed to set TPIDR2 in child\n");
210 			exit(0);
211 		}
212 	}
213 
214 	for (;;) {
215 		waiting = wait4(ret, &status, __WCLONE, NULL);
216 
217 		if (waiting < 0) {
218 			if (errno == EINTR)
219 				continue;
220 			putstr("# wait4() failed: ");
221 			putnum(errno);
222 			putstr("\n");
223 			return 0;
224 		}
225 		if (waiting != ret) {
226 			putstr("# wait4() returned wrong PID ");
227 			putnum(waiting);
228 			putstr("\n");
229 			return 0;
230 		}
231 
232 		if (!WIFEXITED(status)) {
233 			putstr("# child did not exit\n");
234 			return 0;
235 		}
236 
237 		if (parent != get_tpidr2()) {
238 			putstr("# TPIDR2 corrupted in parent\n");
239 			return 0;
240 		}
241 
242 		return WEXITSTATUS(status);
243 	}
244 }
245 
246 #define run_test(name)			     \
247 	if (name()) {			     \
248 		tests_passed++;		     \
249 	} else {			     \
250 		tests_failed++;		     \
251 		putstr("not ");		     \
252 	}				     \
253 	putstr("ok ");			     \
254 	putnum(++tests_run);		     \
255 	putstr(" " #name "\n");
256 
257 int main(int argc, char **argv)
258 {
259 	int ret, i;
260 
261 	putstr("TAP version 13\n");
262 	putstr("1..");
263 	putnum(EXPECTED_TESTS);
264 	putstr("\n");
265 
266 	putstr("# PID: ");
267 	putnum(getpid());
268 	putstr("\n");
269 
270 	/*
271 	 * This test is run with nolibc which doesn't support hwcap and
272 	 * it's probably disproportionate to implement so instead check
273 	 * for the default vector length configuration in /proc.
274 	 */
275 	ret = open("/proc/sys/abi/sme_default_vector_length", O_RDONLY, 0);
276 	if (ret >= 0) {
277 		run_test(default_value);
278 		run_test(write_read);
279 		run_test(write_sleep_read);
280 		run_test(write_fork_read);
281 		run_test(write_clone_read);
282 
283 	} else {
284 		putstr("# SME support not present\n");
285 
286 		for (i = 0; i < EXPECTED_TESTS; i++) {
287 			putstr("ok ");
288 			putnum(i);
289 			putstr(" skipped, TPIDR2 not supported\n");
290 		}
291 
292 		tests_skipped += EXPECTED_TESTS;
293 	}
294 
295 	print_summary();
296 
297 	return 0;
298 }
299