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 ".globl __test_function\n"
49 "__test_function:\n"
50 "incq (%rdi)\n"
51 "ret\n");
52 #else
53 static void __test_function(volatile long *ptr)
54 {
55 *ptr = 0x1234;
56 }
57 #endif
58
59 static noinline int test_function(void)
60 {
61 __test_function(&the_var);
62 the_var++;
63 return time(NULL);
64 }
65
66 static void sig_handler_2(int signum __maybe_unused,
67 siginfo_t *oh __maybe_unused,
68 void *uc __maybe_unused)
69 {
70 overflows_2++;
71 if (overflows_2 > 10) {
72 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
73 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
74 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
75 }
76 }
77
78 static void sig_handler(int signum __maybe_unused,
79 siginfo_t *oh __maybe_unused,
80 void *uc __maybe_unused)
81 {
82 overflows++;
83
84 if (overflows > 10) {
85 /*
86 * This should be executed only once during
87 * this test, if we are here for the 10th
88 * time, consider this the recursive issue.
89 *
90 * We can get out of here by disable events,
91 * so no new SIGIO is delivered.
92 */
93 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
94 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
95 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
96 }
97 }
98
99 static int __event(bool is_x, void *addr, int sig)
100 {
101 struct perf_event_attr pe;
102 int fd;
103
104 memset(&pe, 0, sizeof(struct perf_event_attr));
105 pe.type = PERF_TYPE_BREAKPOINT;
106 pe.size = sizeof(struct perf_event_attr);
107
108 pe.config = 0;
109 pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
110 pe.bp_addr = (unsigned long) addr;
111 pe.bp_len = sizeof(long);
112
113 pe.sample_period = 1;
114 pe.sample_type = PERF_SAMPLE_IP;
115 pe.wakeup_events = 1;
116
117 pe.disabled = 1;
118 pe.exclude_kernel = 1;
119 pe.exclude_hv = 1;
120
121 fd = sys_perf_event_open(&pe, 0, -1, -1,
122 perf_event_open_cloexec_flag());
123 if (fd < 0) {
124 pr_debug("failed opening event %llx\n", pe.config);
125 return TEST_FAIL;
126 }
127
128 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
129 fcntl(fd, F_SETSIG, sig);
130 fcntl(fd, F_SETOWN, getpid());
131
132 ioctl(fd, PERF_EVENT_IOC_RESET, 0);
133
134 return fd;
135 }
136
137 static int bp_event(void *addr, int sig)
138 {
139 return __event(true, addr, sig);
140 }
141
142 static int wp_event(void *addr, int sig)
143 {
144 return __event(false, addr, sig);
145 }
146
147 static long long bp_count(int fd)
148 {
149 long long count;
150 int ret;
151
152 ret = read(fd, &count, sizeof(long long));
153 if (ret != sizeof(long long)) {
154 pr_debug("failed to read: %d\n", ret);
155 return TEST_FAIL;
156 }
157
158 return count;
159 }
160
161 int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
162 {
163 struct sigaction sa;
164 long long count1, count2, count3;
165
166 /* setup SIGIO signal handler */
167 memset(&sa, 0, sizeof(struct sigaction));
168 sa.sa_sigaction = (void *) sig_handler;
169 sa.sa_flags = SA_SIGINFO;
170
171 if (sigaction(SIGIO, &sa, NULL) < 0) {
172 pr_debug("failed setting up signal handler\n");
173 return TEST_FAIL;
174 }
175
176 sa.sa_sigaction = (void *) sig_handler_2;
177 if (sigaction(SIGUSR1, &sa, NULL) < 0) {
178 pr_debug("failed setting up signal handler 2\n");
179 return TEST_FAIL;
180 }
181
182 /*
183 * We create following events:
184 *
185 * fd1 - breakpoint event on __test_function with SIGIO
186 * signal configured. We should get signal
187 * notification each time the breakpoint is hit
188 *
189 * fd2 - breakpoint event on sig_handler with SIGUSR1
190 * configured. We should get SIGUSR1 each time when
191 * breakpoint is hit
192 *
193 * fd3 - watchpoint event on __test_function with SIGIO
194 * configured.
195 *
196 * Following processing should happen:
197 * Exec: Action: Result:
198 * incq (%rdi) - fd1 event breakpoint hit -> count1 == 1
199 * - SIGIO is delivered
200 * sig_handler - fd2 event breakpoint hit -> count2 == 1
201 * - SIGUSR1 is delivered
202 * sig_handler_2 -> overflows_2 == 1 (nested signal)
203 * sys_rt_sigreturn - return from sig_handler_2
204 * overflows++ -> overflows = 1
205 * sys_rt_sigreturn - return from sig_handler
206 * incq (%rdi) - fd3 event watchpoint hit -> count3 == 1 (wp and bp in one insn)
207 * - SIGIO is delivered
208 * sig_handler - fd2 event breakpoint hit -> count2 == 2
209 * - SIGUSR1 is delivered
210 * sig_handler_2 -> overflows_2 == 2 (nested signal)
211 * sys_rt_sigreturn - return from sig_handler_2
212 * overflows++ -> overflows = 2
213 * sys_rt_sigreturn - return from sig_handler
214 * the_var++ - fd3 event watchpoint hit -> count3 == 2 (standalone watchpoint)
215 * - SIGIO is delivered
216 * sig_handler - fd2 event breakpoint hit -> count2 == 3
217 * - SIGUSR1 is delivered
218 * sig_handler_2 -> overflows_2 == 3 (nested signal)
219 * sys_rt_sigreturn - return from sig_handler_2
220 * overflows++ -> overflows == 3
221 * sys_rt_sigreturn - return from sig_handler
222 *
223 * The test case check following error conditions:
224 * - we get stuck in signal handler because of debug
225 * exception being triggered receursively due to
226 * the wrong RF EFLAG management
227 *
228 * - we never trigger the sig_handler breakpoint due
229 * to the rong RF EFLAG management
230 *
231 */
232
233 fd1 = bp_event(__test_function, SIGIO);
234 fd2 = bp_event(sig_handler, SIGUSR1);
235 fd3 = wp_event((void *)&the_var, SIGIO);
236
237 ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
238 ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
239 ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
240
241 /*
242 * Kick off the test by trigering 'fd1'
243 * breakpoint.
244 */
245 test_function();
246
247 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
248 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
249 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
250
251 count1 = bp_count(fd1);
252 count2 = bp_count(fd2);
253 count3 = bp_count(fd3);
254
255 close(fd1);
256 close(fd2);
257 close(fd3);
258
259 pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
260 count1, count2, count3, overflows, overflows_2);
261
262 if (count1 != 1) {
263 if (count1 == 11)
264 pr_debug("failed: RF EFLAG recursion issue detected\n");
265 else
266 pr_debug("failed: wrong count for bp1%lld\n", count1);
267 }
268
269 if (overflows != 3)
270 pr_debug("failed: wrong overflow hit\n");
271
272 if (overflows_2 != 3)
273 pr_debug("failed: wrong overflow_2 hit\n");
274
275 if (count2 != 3)
276 pr_debug("failed: wrong count for bp2\n");
277
278 if (count3 != 2)
279 pr_debug("failed: wrong count for bp3\n");
280
281 return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
282 TEST_OK : TEST_FAIL;
283 }
284
285 bool test__bp_signal_is_supported(void)
286 {
287 /*
288 * PowerPC and S390 do not support creation of instruction
289 * breakpoints using the perf_event interface.
290 *
291 * ARM requires explicit rounding down of the instruction
292 * pointer in Thumb mode, and then requires the single-step
293 * to be handled explicitly in the overflow handler to avoid
294 * stepping into the SIGIO handler and getting stuck on the
295 * breakpointed instruction.
296 *
297 * Since arm64 has the same issue with arm for the single-step
298 * handling, this case also gets suck on the breakpointed
299 * instruction.
300 *
301 * Just disable the test for these architectures until these
302 * issues are resolved.
303 */
304 #if defined(__powerpc__) || defined(__s390x__) || defined(__arm__) || \
305 defined(__aarch64__)
306 return false;
307 #else
308 return true;
309 #endif
310 }