xref: /openbmc/linux/tools/perf/tests/bp_signal.c (revision 4935e2cd)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Inspired by breakpoint overflow test done by
4  * Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests
5  * (git://github.com/deater/perf_event_tests)
6  */
7 
8 /*
9  * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
10  * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
11  */
12 #define __SANE_USERSPACE_TYPES__
13 
14 #include <stdlib.h>
15 #include <stdio.h>
16 #include <unistd.h>
17 #include <string.h>
18 #include <sys/ioctl.h>
19 #include <time.h>
20 #include <fcntl.h>
21 #include <signal.h>
22 #include <sys/mman.h>
23 #include <linux/compiler.h>
24 #include <linux/hw_breakpoint.h>
25 
26 #include "tests.h"
27 #include "debug.h"
28 #include "event.h"
29 #include "perf-sys.h"
30 #include "cloexec.h"
31 
32 static int fd1;
33 static int fd2;
34 static int fd3;
35 static int overflows;
36 static int overflows_2;
37 
38 volatile long the_var;
39 
40 
41 /*
42  * Use ASM to ensure watchpoint and breakpoint can be triggered
43  * at one instruction.
44  */
45 #if defined (__x86_64__)
46 extern void __test_function(volatile long *ptr);
47 asm (
48 	".pushsection .text;"
49 	".globl __test_function\n"
50 	".type __test_function, @function;"
51 	"__test_function:\n"
52 	"incq (%rdi)\n"
53 	"ret\n"
54 	".popsection\n");
55 #else
__test_function(volatile long * ptr)56 static void __test_function(volatile long *ptr)
57 {
58 	*ptr = 0x1234;
59 }
60 #endif
61 
test_function(void)62 static noinline int test_function(void)
63 {
64 	__test_function(&the_var);
65 	the_var++;
66 	return time(NULL);
67 }
68 
sig_handler_2(int signum __maybe_unused,siginfo_t * oh __maybe_unused,void * uc __maybe_unused)69 static void sig_handler_2(int signum __maybe_unused,
70 			  siginfo_t *oh __maybe_unused,
71 			  void *uc __maybe_unused)
72 {
73 	overflows_2++;
74 	if (overflows_2 > 10) {
75 		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
76 		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
77 		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
78 	}
79 }
80 
sig_handler(int signum __maybe_unused,siginfo_t * oh __maybe_unused,void * uc __maybe_unused)81 static void sig_handler(int signum __maybe_unused,
82 			siginfo_t *oh __maybe_unused,
83 			void *uc __maybe_unused)
84 {
85 	overflows++;
86 
87 	if (overflows > 10) {
88 		/*
89 		 * This should be executed only once during
90 		 * this test, if we are here for the 10th
91 		 * time, consider this the recursive issue.
92 		 *
93 		 * We can get out of here by disable events,
94 		 * so no new SIGIO is delivered.
95 		 */
96 		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
97 		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
98 		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
99 	}
100 }
101 
__event(bool is_x,void * addr,int sig)102 static int __event(bool is_x, void *addr, int sig)
103 {
104 	struct perf_event_attr pe;
105 	int fd;
106 
107 	memset(&pe, 0, sizeof(struct perf_event_attr));
108 	pe.type = PERF_TYPE_BREAKPOINT;
109 	pe.size = sizeof(struct perf_event_attr);
110 
111 	pe.config = 0;
112 	pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
113 	pe.bp_addr = (unsigned long) addr;
114 	pe.bp_len = sizeof(long);
115 
116 	pe.sample_period = 1;
117 	pe.sample_type = PERF_SAMPLE_IP;
118 	pe.wakeup_events = 1;
119 
120 	pe.disabled = 1;
121 	pe.exclude_kernel = 1;
122 	pe.exclude_hv = 1;
123 
124 	fd = sys_perf_event_open(&pe, 0, -1, -1,
125 				 perf_event_open_cloexec_flag());
126 	if (fd < 0) {
127 		pr_debug("failed opening event %llx\n", pe.config);
128 		return TEST_FAIL;
129 	}
130 
131 	fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
132 	fcntl(fd, F_SETSIG, sig);
133 	fcntl(fd, F_SETOWN, getpid());
134 
135 	ioctl(fd, PERF_EVENT_IOC_RESET, 0);
136 
137 	return fd;
138 }
139 
bp_event(void * addr,int sig)140 static int bp_event(void *addr, int sig)
141 {
142 	return __event(true, addr, sig);
143 }
144 
wp_event(void * addr,int sig)145 static int wp_event(void *addr, int sig)
146 {
147 	return __event(false, addr, sig);
148 }
149 
bp_count(int fd)150 static long long bp_count(int fd)
151 {
152 	long long count;
153 	int ret;
154 
155 	ret = read(fd, &count, sizeof(long long));
156 	if (ret != sizeof(long long)) {
157 		pr_debug("failed to read: %d\n", ret);
158 		return TEST_FAIL;
159 	}
160 
161 	return count;
162 }
163 
test__bp_signal(struct test_suite * test __maybe_unused,int subtest __maybe_unused)164 static int test__bp_signal(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
165 {
166 	struct sigaction sa;
167 	long long count1, count2, count3;
168 
169 	if (!BP_SIGNAL_IS_SUPPORTED) {
170 		pr_debug("Test not supported on this architecture");
171 		return TEST_SKIP;
172 	}
173 
174 	/* setup SIGIO signal handler */
175 	memset(&sa, 0, sizeof(struct sigaction));
176 	sa.sa_sigaction = (void *) sig_handler;
177 	sa.sa_flags = SA_SIGINFO;
178 
179 	if (sigaction(SIGIO, &sa, NULL) < 0) {
180 		pr_debug("failed setting up signal handler\n");
181 		return TEST_FAIL;
182 	}
183 
184 	sa.sa_sigaction = (void *) sig_handler_2;
185 	if (sigaction(SIGUSR1, &sa, NULL) < 0) {
186 		pr_debug("failed setting up signal handler 2\n");
187 		return TEST_FAIL;
188 	}
189 
190 	/*
191 	 * We create following events:
192 	 *
193 	 * fd1 - breakpoint event on __test_function with SIGIO
194 	 *       signal configured. We should get signal
195 	 *       notification each time the breakpoint is hit
196 	 *
197 	 * fd2 - breakpoint event on sig_handler with SIGUSR1
198 	 *       configured. We should get SIGUSR1 each time when
199 	 *       breakpoint is hit
200 	 *
201 	 * fd3 - watchpoint event on __test_function with SIGIO
202 	 *       configured.
203 	 *
204 	 * Following processing should happen:
205 	 *   Exec:               Action:                       Result:
206 	 *   incq (%rdi)       - fd1 event breakpoint hit   -> count1 == 1
207 	 *                     - SIGIO is delivered
208 	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 1
209 	 *                     - SIGUSR1 is delivered
210 	 *   sig_handler_2                                  -> overflows_2 == 1  (nested signal)
211 	 *   sys_rt_sigreturn  - return from sig_handler_2
212 	 *   overflows++                                    -> overflows = 1
213 	 *   sys_rt_sigreturn  - return from sig_handler
214 	 *   incq (%rdi)       - fd3 event watchpoint hit   -> count3 == 1       (wp and bp in one insn)
215 	 *                     - SIGIO is delivered
216 	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 2
217 	 *                     - SIGUSR1 is delivered
218 	 *   sig_handler_2                                  -> overflows_2 == 2  (nested signal)
219 	 *   sys_rt_sigreturn  - return from sig_handler_2
220 	 *   overflows++                                    -> overflows = 2
221 	 *   sys_rt_sigreturn  - return from sig_handler
222 	 *   the_var++         - fd3 event watchpoint hit   -> count3 == 2       (standalone watchpoint)
223 	 *                     - SIGIO is delivered
224 	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 3
225 	 *                     - SIGUSR1 is delivered
226 	 *   sig_handler_2                                  -> overflows_2 == 3  (nested signal)
227 	 *   sys_rt_sigreturn  - return from sig_handler_2
228 	 *   overflows++                                    -> overflows == 3
229 	 *   sys_rt_sigreturn  - return from sig_handler
230 	 *
231 	 * The test case check following error conditions:
232 	 * - we get stuck in signal handler because of debug
233 	 *   exception being triggered recursively due to
234 	 *   the wrong RF EFLAG management
235 	 *
236 	 * - we never trigger the sig_handler breakpoint due
237 	 *   to the wrong RF EFLAG management
238 	 *
239 	 */
240 
241 	fd1 = bp_event(__test_function, SIGIO);
242 	fd2 = bp_event(sig_handler, SIGUSR1);
243 	fd3 = wp_event((void *)&the_var, SIGIO);
244 
245 	ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
246 	ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
247 	ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
248 
249 	/*
250 	 * Kick off the test by triggering 'fd1'
251 	 * breakpoint.
252 	 */
253 	test_function();
254 
255 	ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
256 	ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
257 	ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
258 
259 	count1 = bp_count(fd1);
260 	count2 = bp_count(fd2);
261 	count3 = bp_count(fd3);
262 
263 	close(fd1);
264 	close(fd2);
265 	close(fd3);
266 
267 	pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
268 		 count1, count2, count3, overflows, overflows_2);
269 
270 	if (count1 != 1) {
271 		if (count1 == 11)
272 			pr_debug("failed: RF EFLAG recursion issue detected\n");
273 		else
274 			pr_debug("failed: wrong count for bp1: %lld, expected 1\n", count1);
275 	}
276 
277 	if (overflows != 3)
278 		pr_debug("failed: wrong overflow (%d) hit, expected 3\n", overflows);
279 
280 	if (overflows_2 != 3)
281 		pr_debug("failed: wrong overflow_2 (%d) hit, expected 3\n", overflows_2);
282 
283 	if (count2 != 3)
284 		pr_debug("failed: wrong count for bp2 (%lld), expected 3\n", count2);
285 
286 	if (count3 != 2)
287 		pr_debug("failed: wrong count for bp3 (%lld), expected 2\n", count3);
288 
289 	return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
290 		TEST_OK : TEST_FAIL;
291 }
292 
293 DEFINE_SUITE("Breakpoint overflow signal handler", bp_signal);
294