xref: /openbmc/linux/tools/perf/tests/bp_signal.c (revision 4da722ca)
1 /*
2  * Inspired by breakpoint overflow test done by
3  * Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests
4  * (git://github.com/deater/perf_event_tests)
5  */
6 
7 /*
8  * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
9  * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
10  */
11 #define __SANE_USERSPACE_TYPES__
12 
13 #include <stdlib.h>
14 #include <stdio.h>
15 #include <unistd.h>
16 #include <string.h>
17 #include <sys/ioctl.h>
18 #include <time.h>
19 #include <fcntl.h>
20 #include <signal.h>
21 #include <sys/mman.h>
22 #include <linux/compiler.h>
23 #include <linux/hw_breakpoint.h>
24 
25 #include "tests.h"
26 #include "debug.h"
27 #include "perf.h"
28 #include "cloexec.h"
29 
30 static int fd1;
31 static int fd2;
32 static int fd3;
33 static int overflows;
34 static int overflows_2;
35 
36 volatile long the_var;
37 
38 
39 /*
40  * Use ASM to ensure watchpoint and breakpoint can be triggered
41  * at one instruction.
42  */
43 #if defined (__x86_64__)
44 extern void __test_function(volatile long *ptr);
45 asm (
46 	".globl __test_function\n"
47 	"__test_function:\n"
48 	"incq (%rdi)\n"
49 	"ret\n");
50 #elif defined (__aarch64__)
51 extern void __test_function(volatile long *ptr);
52 asm (
53 	".globl __test_function\n"
54 	"__test_function:\n"
55 	"str x30, [x0]\n"
56 	"ret\n");
57 
58 #else
59 static void __test_function(volatile long *ptr)
60 {
61 	*ptr = 0x1234;
62 }
63 #endif
64 
65 static noinline int test_function(void)
66 {
67 	__test_function(&the_var);
68 	the_var++;
69 	return time(NULL);
70 }
71 
72 static void sig_handler_2(int signum __maybe_unused,
73 			  siginfo_t *oh __maybe_unused,
74 			  void *uc __maybe_unused)
75 {
76 	overflows_2++;
77 	if (overflows_2 > 10) {
78 		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
79 		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
80 		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
81 	}
82 }
83 
84 static void sig_handler(int signum __maybe_unused,
85 			siginfo_t *oh __maybe_unused,
86 			void *uc __maybe_unused)
87 {
88 	overflows++;
89 
90 	if (overflows > 10) {
91 		/*
92 		 * This should be executed only once during
93 		 * this test, if we are here for the 10th
94 		 * time, consider this the recursive issue.
95 		 *
96 		 * We can get out of here by disable events,
97 		 * so no new SIGIO is delivered.
98 		 */
99 		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
100 		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
101 		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
102 	}
103 }
104 
105 static int __event(bool is_x, void *addr, int sig)
106 {
107 	struct perf_event_attr pe;
108 	int fd;
109 
110 	memset(&pe, 0, sizeof(struct perf_event_attr));
111 	pe.type = PERF_TYPE_BREAKPOINT;
112 	pe.size = sizeof(struct perf_event_attr);
113 
114 	pe.config = 0;
115 	pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
116 	pe.bp_addr = (unsigned long) addr;
117 	pe.bp_len = sizeof(long);
118 
119 	pe.sample_period = 1;
120 	pe.sample_type = PERF_SAMPLE_IP;
121 	pe.wakeup_events = 1;
122 
123 	pe.disabled = 1;
124 	pe.exclude_kernel = 1;
125 	pe.exclude_hv = 1;
126 
127 	fd = sys_perf_event_open(&pe, 0, -1, -1,
128 				 perf_event_open_cloexec_flag());
129 	if (fd < 0) {
130 		pr_debug("failed opening event %llx\n", pe.config);
131 		return TEST_FAIL;
132 	}
133 
134 	fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
135 	fcntl(fd, F_SETSIG, sig);
136 	fcntl(fd, F_SETOWN, getpid());
137 
138 	ioctl(fd, PERF_EVENT_IOC_RESET, 0);
139 
140 	return fd;
141 }
142 
143 static int bp_event(void *addr, int sig)
144 {
145 	return __event(true, addr, sig);
146 }
147 
148 static int wp_event(void *addr, int sig)
149 {
150 	return __event(false, addr, sig);
151 }
152 
153 static long long bp_count(int fd)
154 {
155 	long long count;
156 	int ret;
157 
158 	ret = read(fd, &count, sizeof(long long));
159 	if (ret != sizeof(long long)) {
160 		pr_debug("failed to read: %d\n", ret);
161 		return TEST_FAIL;
162 	}
163 
164 	return count;
165 }
166 
167 int test__bp_signal(int subtest __maybe_unused)
168 {
169 	struct sigaction sa;
170 	long long count1, count2, count3;
171 
172 	/* setup SIGIO signal handler */
173 	memset(&sa, 0, sizeof(struct sigaction));
174 	sa.sa_sigaction = (void *) sig_handler;
175 	sa.sa_flags = SA_SIGINFO;
176 
177 	if (sigaction(SIGIO, &sa, NULL) < 0) {
178 		pr_debug("failed setting up signal handler\n");
179 		return TEST_FAIL;
180 	}
181 
182 	sa.sa_sigaction = (void *) sig_handler_2;
183 	if (sigaction(SIGUSR1, &sa, NULL) < 0) {
184 		pr_debug("failed setting up signal handler 2\n");
185 		return TEST_FAIL;
186 	}
187 
188 	/*
189 	 * We create following events:
190 	 *
191 	 * fd1 - breakpoint event on __test_function with SIGIO
192 	 *       signal configured. We should get signal
193 	 *       notification each time the breakpoint is hit
194 	 *
195 	 * fd2 - breakpoint event on sig_handler with SIGUSR1
196 	 *       configured. We should get SIGUSR1 each time when
197 	 *       breakpoint is hit
198 	 *
199 	 * fd3 - watchpoint event on __test_function with SIGIO
200 	 *       configured.
201 	 *
202 	 * Following processing should happen:
203 	 *   Exec:               Action:                       Result:
204 	 *   incq (%rdi)       - fd1 event breakpoint hit   -> count1 == 1
205 	 *                     - SIGIO is delivered
206 	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 1
207 	 *                     - SIGUSR1 is delivered
208 	 *   sig_handler_2                                  -> overflows_2 == 1  (nested signal)
209 	 *   sys_rt_sigreturn  - return from sig_handler_2
210 	 *   overflows++                                    -> overflows = 1
211 	 *   sys_rt_sigreturn  - return from sig_handler
212 	 *   incq (%rdi)       - fd3 event watchpoint hit   -> count3 == 1       (wp and bp in one insn)
213 	 *                     - SIGIO is delivered
214 	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 2
215 	 *                     - SIGUSR1 is delivered
216 	 *   sig_handler_2                                  -> overflows_2 == 2  (nested signal)
217 	 *   sys_rt_sigreturn  - return from sig_handler_2
218 	 *   overflows++                                    -> overflows = 2
219 	 *   sys_rt_sigreturn  - return from sig_handler
220 	 *   the_var++         - fd3 event watchpoint hit   -> count3 == 2       (standalone watchpoint)
221 	 *                     - SIGIO is delivered
222 	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 3
223 	 *                     - SIGUSR1 is delivered
224 	 *   sig_handler_2                                  -> overflows_2 == 3  (nested signal)
225 	 *   sys_rt_sigreturn  - return from sig_handler_2
226 	 *   overflows++                                    -> overflows == 3
227 	 *   sys_rt_sigreturn  - return from sig_handler
228 	 *
229 	 * The test case check following error conditions:
230 	 * - we get stuck in signal handler because of debug
231 	 *   exception being triggered receursively due to
232 	 *   the wrong RF EFLAG management
233 	 *
234 	 * - we never trigger the sig_handler breakpoint due
235 	 *   to the rong RF EFLAG management
236 	 *
237 	 */
238 
239 	fd1 = bp_event(__test_function, SIGIO);
240 	fd2 = bp_event(sig_handler, SIGUSR1);
241 	fd3 = wp_event((void *)&the_var, SIGIO);
242 
243 	ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
244 	ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
245 	ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
246 
247 	/*
248 	 * Kick off the test by trigering 'fd1'
249 	 * breakpoint.
250 	 */
251 	test_function();
252 
253 	ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
254 	ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
255 	ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
256 
257 	count1 = bp_count(fd1);
258 	count2 = bp_count(fd2);
259 	count3 = bp_count(fd3);
260 
261 	close(fd1);
262 	close(fd2);
263 	close(fd3);
264 
265 	pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
266 		 count1, count2, count3, overflows, overflows_2);
267 
268 	if (count1 != 1) {
269 		if (count1 == 11)
270 			pr_debug("failed: RF EFLAG recursion issue detected\n");
271 		else
272 			pr_debug("failed: wrong count for bp1%lld\n", count1);
273 	}
274 
275 	if (overflows != 3)
276 		pr_debug("failed: wrong overflow hit\n");
277 
278 	if (overflows_2 != 3)
279 		pr_debug("failed: wrong overflow_2 hit\n");
280 
281 	if (count2 != 3)
282 		pr_debug("failed: wrong count for bp2\n");
283 
284 	if (count3 != 2)
285 		pr_debug("failed: wrong count for bp3\n");
286 
287 	return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
288 		TEST_OK : TEST_FAIL;
289 }
290 
291 bool test__bp_signal_is_supported(void)
292 {
293 /*
294  * The powerpc so far does not have support to even create
295  * instruction breakpoint using the perf event interface.
296  * Once it's there we can release this.
297  */
298 #ifdef __powerpc__
299 	return false;
300 #else
301 	return true;
302 #endif
303 }
304