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 #elif defined (__aarch64__)
53 extern void __test_function(volatile long *ptr);
54 asm (
55 ".globl __test_function\n"
56 "__test_function:\n"
57 "str x30, [x0]\n"
58 "ret\n");
59
60 #else
__test_function(volatile long * ptr)61 static void __test_function(volatile long *ptr)
62 {
63 *ptr = 0x1234;
64 }
65 #endif
66
test_function(void)67 static noinline int test_function(void)
68 {
69 __test_function(&the_var);
70 the_var++;
71 return time(NULL);
72 }
73
sig_handler_2(int signum __maybe_unused,siginfo_t * oh __maybe_unused,void * uc __maybe_unused)74 static void sig_handler_2(int signum __maybe_unused,
75 siginfo_t *oh __maybe_unused,
76 void *uc __maybe_unused)
77 {
78 overflows_2++;
79 if (overflows_2 > 10) {
80 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
81 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
82 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
83 }
84 }
85
sig_handler(int signum __maybe_unused,siginfo_t * oh __maybe_unused,void * uc __maybe_unused)86 static void sig_handler(int signum __maybe_unused,
87 siginfo_t *oh __maybe_unused,
88 void *uc __maybe_unused)
89 {
90 overflows++;
91
92 if (overflows > 10) {
93 /*
94 * This should be executed only once during
95 * this test, if we are here for the 10th
96 * time, consider this the recursive issue.
97 *
98 * We can get out of here by disable events,
99 * so no new SIGIO is delivered.
100 */
101 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
102 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
103 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
104 }
105 }
106
__event(bool is_x,void * addr,int sig)107 static int __event(bool is_x, void *addr, int sig)
108 {
109 struct perf_event_attr pe;
110 int fd;
111
112 memset(&pe, 0, sizeof(struct perf_event_attr));
113 pe.type = PERF_TYPE_BREAKPOINT;
114 pe.size = sizeof(struct perf_event_attr);
115
116 pe.config = 0;
117 pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
118 pe.bp_addr = (unsigned long) addr;
119 pe.bp_len = sizeof(long);
120
121 pe.sample_period = 1;
122 pe.sample_type = PERF_SAMPLE_IP;
123 pe.wakeup_events = 1;
124
125 pe.disabled = 1;
126 pe.exclude_kernel = 1;
127 pe.exclude_hv = 1;
128
129 fd = sys_perf_event_open(&pe, 0, -1, -1,
130 perf_event_open_cloexec_flag());
131 if (fd < 0) {
132 pr_debug("failed opening event %llx\n", pe.config);
133 return TEST_FAIL;
134 }
135
136 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
137 fcntl(fd, F_SETSIG, sig);
138 fcntl(fd, F_SETOWN, getpid());
139
140 ioctl(fd, PERF_EVENT_IOC_RESET, 0);
141
142 return fd;
143 }
144
bp_event(void * addr,int sig)145 static int bp_event(void *addr, int sig)
146 {
147 return __event(true, addr, sig);
148 }
149
wp_event(void * addr,int sig)150 static int wp_event(void *addr, int sig)
151 {
152 return __event(false, addr, sig);
153 }
154
bp_count(int fd)155 static long long bp_count(int fd)
156 {
157 long long count;
158 int ret;
159
160 ret = read(fd, &count, sizeof(long long));
161 if (ret != sizeof(long long)) {
162 pr_debug("failed to read: %d\n", ret);
163 return TEST_FAIL;
164 }
165
166 return count;
167 }
168
test__bp_signal(struct test * test __maybe_unused,int subtest __maybe_unused)169 int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
170 {
171 struct sigaction sa;
172 long long count1, count2, count3;
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 receursively due to
234 * the wrong RF EFLAG management
235 *
236 * - we never trigger the sig_handler breakpoint due
237 * to the rong 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 trigering '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\n", count1);
275 }
276
277 if (overflows != 3)
278 pr_debug("failed: wrong overflow hit\n");
279
280 if (overflows_2 != 3)
281 pr_debug("failed: wrong overflow_2 hit\n");
282
283 if (count2 != 3)
284 pr_debug("failed: wrong count for bp2\n");
285
286 if (count3 != 2)
287 pr_debug("failed: wrong count for bp3\n");
288
289 return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
290 TEST_OK : TEST_FAIL;
291 }
292
test__bp_signal_is_supported(void)293 bool test__bp_signal_is_supported(void)
294 {
295 /*
296 * PowerPC and S390 do not support creation of instruction
297 * breakpoints using the perf_event interface.
298 *
299 * ARM requires explicit rounding down of the instruction
300 * pointer in Thumb mode, and then requires the single-step
301 * to be handled explicitly in the overflow handler to avoid
302 * stepping into the SIGIO handler and getting stuck on the
303 * breakpointed instruction.
304 *
305 * Just disable the test for these architectures until these
306 * issues are resolved.
307 */
308 #if defined(__powerpc__) || defined(__s390x__) || defined(__arm__)
309 return false;
310 #else
311 return true;
312 #endif
313 }
314
