summaryrefslogtreecommitdiff
path: root/tools/perf/tests/bp_signal.c
blob: ef37353636d87829dbdb8f3d5af7926caccd4930 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
// SPDX-License-Identifier: GPL-2.0
/*
 * Inspired by breakpoint overflow test done by
 * Vince Weaver <vincent.weaver@maine.edu> for perf_event_tests
 * (git://github.com/deater/perf_event_tests)
 */

/*
 * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
 * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
 */
#define __SANE_USERSPACE_TYPES__

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/ioctl.h>
#include <time.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/mman.h>
#include <linux/compiler.h>
#include <linux/hw_breakpoint.h>

#include "tests.h"
#include "debug.h"
#include "event.h"
#include "perf-sys.h"
#include "cloexec.h"

static int fd1;
static int fd2;
static int fd3;
static int overflows;
static int overflows_2;

volatile long the_var;


/*
 * Use ASM to ensure watchpoint and breakpoint can be triggered
 * at one instruction.
 */
#if defined (__x86_64__)
extern void __test_function(volatile long *ptr);
asm (
	".pushsection .text;"
	".globl __test_function\n"
	".type __test_function, @function;"
	"__test_function:\n"
	"incq (%rdi)\n"
	"ret\n"
	".popsection\n");
#else
static void __test_function(volatile long *ptr)
{
	*ptr = 0x1234;
}
#endif

static noinline int test_function(void)
{
	__test_function(&the_var);
	the_var++;
	return time(NULL);
}

static void sig_handler_2(int signum __maybe_unused,
			  siginfo_t *oh __maybe_unused,
			  void *uc __maybe_unused)
{
	overflows_2++;
	if (overflows_2 > 10) {
		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
	}
}

static void sig_handler(int signum __maybe_unused,
			siginfo_t *oh __maybe_unused,
			void *uc __maybe_unused)
{
	overflows++;

	if (overflows > 10) {
		/*
		 * This should be executed only once during
		 * this test, if we are here for the 10th
		 * time, consider this the recursive issue.
		 *
		 * We can get out of here by disable events,
		 * so no new SIGIO is delivered.
		 */
		ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
		ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
		ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
	}
}

static int __event(bool is_x, void *addr, int sig)
{
	struct perf_event_attr pe;
	int fd;

	memset(&pe, 0, sizeof(struct perf_event_attr));
	pe.type = PERF_TYPE_BREAKPOINT;
	pe.size = sizeof(struct perf_event_attr);

	pe.config = 0;
	pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
	pe.bp_addr = (unsigned long) addr;
	pe.bp_len = sizeof(long);

	pe.sample_period = 1;
	pe.sample_type = PERF_SAMPLE_IP;
	pe.wakeup_events = 1;

	pe.disabled = 1;
	pe.exclude_kernel = 1;
	pe.exclude_hv = 1;

	fd = sys_perf_event_open(&pe, 0, -1, -1,
				 perf_event_open_cloexec_flag());
	if (fd < 0) {
		pr_debug("failed opening event %llx\n", pe.config);
		return TEST_FAIL;
	}

	fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
	fcntl(fd, F_SETSIG, sig);
	fcntl(fd, F_SETOWN, getpid());

	ioctl(fd, PERF_EVENT_IOC_RESET, 0);

	return fd;
}

static int bp_event(void *addr, int sig)
{
	return __event(true, addr, sig);
}

static int wp_event(void *addr, int sig)
{
	return __event(false, addr, sig);
}

static long long bp_count(int fd)
{
	long long count;
	int ret;

	ret = read(fd, &count, sizeof(long long));
	if (ret != sizeof(long long)) {
		pr_debug("failed to read: %d\n", ret);
		return TEST_FAIL;
	}

	return count;
}

int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
{
	struct sigaction sa;
	long long count1, count2, count3;

	/* setup SIGIO signal handler */
	memset(&sa, 0, sizeof(struct sigaction));
	sa.sa_sigaction = (void *) sig_handler;
	sa.sa_flags = SA_SIGINFO;

	if (sigaction(SIGIO, &sa, NULL) < 0) {
		pr_debug("failed setting up signal handler\n");
		return TEST_FAIL;
	}

	sa.sa_sigaction = (void *) sig_handler_2;
	if (sigaction(SIGUSR1, &sa, NULL) < 0) {
		pr_debug("failed setting up signal handler 2\n");
		return TEST_FAIL;
	}

	/*
	 * We create following events:
	 *
	 * fd1 - breakpoint event on __test_function with SIGIO
	 *       signal configured. We should get signal
	 *       notification each time the breakpoint is hit
	 *
	 * fd2 - breakpoint event on sig_handler with SIGUSR1
	 *       configured. We should get SIGUSR1 each time when
	 *       breakpoint is hit
	 *
	 * fd3 - watchpoint event on __test_function with SIGIO
	 *       configured.
	 *
	 * Following processing should happen:
	 *   Exec:               Action:                       Result:
	 *   incq (%rdi)       - fd1 event breakpoint hit   -> count1 == 1
	 *                     - SIGIO is delivered
	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 1
	 *                     - SIGUSR1 is delivered
	 *   sig_handler_2                                  -> overflows_2 == 1  (nested signal)
	 *   sys_rt_sigreturn  - return from sig_handler_2
	 *   overflows++                                    -> overflows = 1
	 *   sys_rt_sigreturn  - return from sig_handler
	 *   incq (%rdi)       - fd3 event watchpoint hit   -> count3 == 1       (wp and bp in one insn)
	 *                     - SIGIO is delivered
	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 2
	 *                     - SIGUSR1 is delivered
	 *   sig_handler_2                                  -> overflows_2 == 2  (nested signal)
	 *   sys_rt_sigreturn  - return from sig_handler_2
	 *   overflows++                                    -> overflows = 2
	 *   sys_rt_sigreturn  - return from sig_handler
	 *   the_var++         - fd3 event watchpoint hit   -> count3 == 2       (standalone watchpoint)
	 *                     - SIGIO is delivered
	 *   sig_handler       - fd2 event breakpoint hit   -> count2 == 3
	 *                     - SIGUSR1 is delivered
	 *   sig_handler_2                                  -> overflows_2 == 3  (nested signal)
	 *   sys_rt_sigreturn  - return from sig_handler_2
	 *   overflows++                                    -> overflows == 3
	 *   sys_rt_sigreturn  - return from sig_handler
	 *
	 * The test case check following error conditions:
	 * - we get stuck in signal handler because of debug
	 *   exception being triggered recursively due to
	 *   the wrong RF EFLAG management
	 *
	 * - we never trigger the sig_handler breakpoint due
	 *   to the wrong RF EFLAG management
	 *
	 */

	fd1 = bp_event(__test_function, SIGIO);
	fd2 = bp_event(sig_handler, SIGUSR1);
	fd3 = wp_event((void *)&the_var, SIGIO);

	ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
	ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
	ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);

	/*
	 * Kick off the test by triggering 'fd1'
	 * breakpoint.
	 */
	test_function();

	ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
	ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
	ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);

	count1 = bp_count(fd1);
	count2 = bp_count(fd2);
	count3 = bp_count(fd3);

	close(fd1);
	close(fd2);
	close(fd3);

	pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
		 count1, count2, count3, overflows, overflows_2);

	if (count1 != 1) {
		if (count1 == 11)
			pr_debug("failed: RF EFLAG recursion issue detected\n");
		else
			pr_debug("failed: wrong count for bp1: %lld, expected 1\n", count1);
	}

	if (overflows != 3)
		pr_debug("failed: wrong overflow (%d) hit, expected 3\n", overflows);

	if (overflows_2 != 3)
		pr_debug("failed: wrong overflow_2 (%d) hit, expected 3\n", overflows_2);

	if (count2 != 3)
		pr_debug("failed: wrong count for bp2 (%lld), expected 3\n", count2);

	if (count3 != 2)
		pr_debug("failed: wrong count for bp3 (%lld), expected 2\n", count3);

	return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
		TEST_OK : TEST_FAIL;
}

bool test__bp_signal_is_supported(void)
{
	/*
	 * PowerPC and S390 do not support creation of instruction
	 * breakpoints using the perf_event interface.
	 *
	 * ARM requires explicit rounding down of the instruction
	 * pointer in Thumb mode, and then requires the single-step
	 * to be handled explicitly in the overflow handler to avoid
	 * stepping into the SIGIO handler and getting stuck on the
	 * breakpointed instruction.
	 *
	 * Since arm64 has the same issue with arm for the single-step
	 * handling, this case also gets stuck on the breakpointed
	 * instruction.
	 *
	 * Just disable the test for these architectures until these
	 * issues are resolved.
	 */
#if defined(__powerpc__) || defined(__s390x__) || defined(__arm__) || \
    defined(__aarch64__)
	return false;
#else
	return true;
#endif
}