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
putstr(const char * str)10 static void putstr(const char *str)
11 {
12 write(1, str, strlen(str));
13 }
14
putnum(unsigned int num)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
set_tpidr2(uint64_t val)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
get_tpidr2(void)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
print_summary(void)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 */
default_value(void)68 static int default_value(void)
69 {
70 return get_tpidr2() == 0;
71 }
72
73 /* If we set TPIDR2 we should read that value */
write_read(void)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 */
write_sleep_read(void)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 */
write_fork_read(void)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 */
sys_clone(unsigned long clone_flags,unsigned long newsp,int * parent_tidptr,unsigned long tls,int * child_tidptr)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 */
write_clone_read(void)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
main(int argc,char ** argv)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