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
56 static void __test_function(volatile long *ptr)
57 {
58 *ptr = 0x1234;
59 }
60 #endif
61
62 static noinline int test_function(void)
63 {
64 __test_function(&the_var);
65 the_var++;
66 return time(NULL);
67 }
68
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
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
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
140 static int bp_event(void *addr, int sig)
141 {
142 return __event(true, addr, sig);
143 }
144
145 static int wp_event(void *addr, int sig)
146 {
147 return __event(false, addr, sig);
148 }
149
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
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
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