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 "perf.h"
29 #include "cloexec.h"
30
31 static int fd1;
32 static int fd2;
33 static int fd3;
34 static int overflows;
35 static int overflows_2;
36
37 volatile long the_var;
38
39
40 /*
41 * Use ASM to ensure watchpoint and breakpoint can be triggered
42 * at one instruction.
43 */
44 #if defined (__x86_64__)
45 extern void __test_function(volatile long *ptr);
46 asm (
47 ".pushsection .text;"
48 ".globl __test_function\n"
49 ".type __test_function, @function;"
50 "__test_function:\n"
51 "incq (%rdi)\n"
52 "ret\n"
53 ".popsection\n");
54 #else
__test_function(volatile long * ptr)55 static void __test_function(volatile long *ptr)
56 {
57 *ptr = 0x1234;
58 }
59 #endif
60
test_function(void)61 static noinline int test_function(void)
62 {
63 __test_function(&the_var);
64 the_var++;
65 return time(NULL);
66 }
67
sig_handler_2(int signum __maybe_unused,siginfo_t * oh __maybe_unused,void * uc __maybe_unused)68 static void sig_handler_2(int signum __maybe_unused,
69 siginfo_t *oh __maybe_unused,
70 void *uc __maybe_unused)
71 {
72 overflows_2++;
73 if (overflows_2 > 10) {
74 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
75 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
76 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
77 }
78 }
79
sig_handler(int signum __maybe_unused,siginfo_t * oh __maybe_unused,void * uc __maybe_unused)80 static void sig_handler(int signum __maybe_unused,
81 siginfo_t *oh __maybe_unused,
82 void *uc __maybe_unused)
83 {
84 overflows++;
85
86 if (overflows > 10) {
87 /*
88 * This should be executed only once during
89 * this test, if we are here for the 10th
90 * time, consider this the recursive issue.
91 *
92 * We can get out of here by disable events,
93 * so no new SIGIO is delivered.
94 */
95 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
96 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
97 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
98 }
99 }
100
__event(bool is_x,void * addr,int sig)101 static int __event(bool is_x, void *addr, int sig)
102 {
103 struct perf_event_attr pe;
104 int fd;
105
106 memset(&pe, 0, sizeof(struct perf_event_attr));
107 pe.type = PERF_TYPE_BREAKPOINT;
108 pe.size = sizeof(struct perf_event_attr);
109
110 pe.config = 0;
111 pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
112 pe.bp_addr = (unsigned long) addr;
113 pe.bp_len = sizeof(long);
114
115 pe.sample_period = 1;
116 pe.sample_type = PERF_SAMPLE_IP;
117 pe.wakeup_events = 1;
118
119 pe.disabled = 1;
120 pe.exclude_kernel = 1;
121 pe.exclude_hv = 1;
122
123 fd = sys_perf_event_open(&pe, 0, -1, -1,
124 perf_event_open_cloexec_flag());
125 if (fd < 0) {
126 pr_debug("failed opening event %llx\n", pe.config);
127 return TEST_FAIL;
128 }
129
130 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
131 fcntl(fd, F_SETSIG, sig);
132 fcntl(fd, F_SETOWN, getpid());
133
134 ioctl(fd, PERF_EVENT_IOC_RESET, 0);
135
136 return fd;
137 }
138
bp_event(void * addr,int sig)139 static int bp_event(void *addr, int sig)
140 {
141 return __event(true, addr, sig);
142 }
143
wp_event(void * addr,int sig)144 static int wp_event(void *addr, int sig)
145 {
146 return __event(false, addr, sig);
147 }
148
bp_count(int fd)149 static long long bp_count(int fd)
150 {
151 long long count;
152 int ret;
153
154 ret = read(fd, &count, sizeof(long long));
155 if (ret != sizeof(long long)) {
156 pr_debug("failed to read: %d\n", ret);
157 return TEST_FAIL;
158 }
159
160 return count;
161 }
162
test__bp_signal(struct test * test __maybe_unused,int subtest __maybe_unused)163 int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
164 {
165 struct sigaction sa;
166 long long count1, count2, count3;
167
168 /* setup SIGIO signal handler */
169 memset(&sa, 0, sizeof(struct sigaction));
170 sa.sa_sigaction = (void *) sig_handler;
171 sa.sa_flags = SA_SIGINFO;
172
173 if (sigaction(SIGIO, &sa, NULL) < 0) {
174 pr_debug("failed setting up signal handler\n");
175 return TEST_FAIL;
176 }
177
178 sa.sa_sigaction = (void *) sig_handler_2;
179 if (sigaction(SIGUSR1, &sa, NULL) < 0) {
180 pr_debug("failed setting up signal handler 2\n");
181 return TEST_FAIL;
182 }
183
184 /*
185 * We create following events:
186 *
187 * fd1 - breakpoint event on __test_function with SIGIO
188 * signal configured. We should get signal
189 * notification each time the breakpoint is hit
190 *
191 * fd2 - breakpoint event on sig_handler with SIGUSR1
192 * configured. We should get SIGUSR1 each time when
193 * breakpoint is hit
194 *
195 * fd3 - watchpoint event on __test_function with SIGIO
196 * configured.
197 *
198 * Following processing should happen:
199 * Exec: Action: Result:
200 * incq (%rdi) - fd1 event breakpoint hit -> count1 == 1
201 * - SIGIO is delivered
202 * sig_handler - fd2 event breakpoint hit -> count2 == 1
203 * - SIGUSR1 is delivered
204 * sig_handler_2 -> overflows_2 == 1 (nested signal)
205 * sys_rt_sigreturn - return from sig_handler_2
206 * overflows++ -> overflows = 1
207 * sys_rt_sigreturn - return from sig_handler
208 * incq (%rdi) - fd3 event watchpoint hit -> count3 == 1 (wp and bp in one insn)
209 * - SIGIO is delivered
210 * sig_handler - fd2 event breakpoint hit -> count2 == 2
211 * - SIGUSR1 is delivered
212 * sig_handler_2 -> overflows_2 == 2 (nested signal)
213 * sys_rt_sigreturn - return from sig_handler_2
214 * overflows++ -> overflows = 2
215 * sys_rt_sigreturn - return from sig_handler
216 * the_var++ - fd3 event watchpoint hit -> count3 == 2 (standalone watchpoint)
217 * - SIGIO is delivered
218 * sig_handler - fd2 event breakpoint hit -> count2 == 3
219 * - SIGUSR1 is delivered
220 * sig_handler_2 -> overflows_2 == 3 (nested signal)
221 * sys_rt_sigreturn - return from sig_handler_2
222 * overflows++ -> overflows == 3
223 * sys_rt_sigreturn - return from sig_handler
224 *
225 * The test case check following error conditions:
226 * - we get stuck in signal handler because of debug
227 * exception being triggered receursively due to
228 * the wrong RF EFLAG management
229 *
230 * - we never trigger the sig_handler breakpoint due
231 * to the rong RF EFLAG management
232 *
233 */
234
235 fd1 = bp_event(__test_function, SIGIO);
236 fd2 = bp_event(sig_handler, SIGUSR1);
237 fd3 = wp_event((void *)&the_var, SIGIO);
238
239 ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
240 ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
241 ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
242
243 /*
244 * Kick off the test by trigering 'fd1'
245 * breakpoint.
246 */
247 test_function();
248
249 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
250 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
251 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
252
253 count1 = bp_count(fd1);
254 count2 = bp_count(fd2);
255 count3 = bp_count(fd3);
256
257 close(fd1);
258 close(fd2);
259 close(fd3);
260
261 pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
262 count1, count2, count3, overflows, overflows_2);
263
264 if (count1 != 1) {
265 if (count1 == 11)
266 pr_debug("failed: RF EFLAG recursion issue detected\n");
267 else
268 pr_debug("failed: wrong count for bp1%lld\n", count1);
269 }
270
271 if (overflows != 3)
272 pr_debug("failed: wrong overflow hit\n");
273
274 if (overflows_2 != 3)
275 pr_debug("failed: wrong overflow_2 hit\n");
276
277 if (count2 != 3)
278 pr_debug("failed: wrong count for bp2\n");
279
280 if (count3 != 2)
281 pr_debug("failed: wrong count for bp3\n");
282
283 return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
284 TEST_OK : TEST_FAIL;
285 }
286
test__bp_signal_is_supported(void)287 bool test__bp_signal_is_supported(void)
288 {
289 /*
290 * PowerPC and S390 do not support creation of instruction
291 * breakpoints using the perf_event interface.
292 *
293 * ARM requires explicit rounding down of the instruction
294 * pointer in Thumb mode, and then requires the single-step
295 * to be handled explicitly in the overflow handler to avoid
296 * stepping into the SIGIO handler and getting stuck on the
297 * breakpointed instruction.
298 *
299 * Since arm64 has the same issue with arm for the single-step
300 * handling, this case also gets suck on the breakpointed
301 * instruction.
302 *
303 * Just disable the test for these architectures until these
304 * issues are resolved.
305 */
306 #if defined(__powerpc__) || defined(__s390x__) || defined(__arm__) || \
307 defined(__aarch64__)
308 return false;
309 #else
310 return true;
311 #endif
312 }
313