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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
31static int fd1;
32static int fd2;
33static int fd3;
34static int overflows;
35static int overflows_2;
36
37volatile 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__)
45extern void __test_function(volatile long *ptr);
46asm (
47 ".globl __test_function\n"
48 "__test_function:\n"
49 "incq (%rdi)\n"
50 "ret\n");
51#elif defined (__aarch64__)
52extern void __test_function(volatile long *ptr);
53asm (
54 ".globl __test_function\n"
55 "__test_function:\n"
56 "str x30, [x0]\n"
57 "ret\n");
58
59#else
60static void __test_function(volatile long *ptr)
61{
62 *ptr = 0x1234;
63}
64#endif
65
66static noinline int test_function(void)
67{
68 __test_function(&the_var);
69 the_var++;
70 return time(NULL);
71}
72
73static void sig_handler_2(int signum __maybe_unused,
74 siginfo_t *oh __maybe_unused,
75 void *uc __maybe_unused)
76{
77 overflows_2++;
78 if (overflows_2 > 10) {
79 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
80 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
81 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
82 }
83}
84
85static void sig_handler(int signum __maybe_unused,
86 siginfo_t *oh __maybe_unused,
87 void *uc __maybe_unused)
88{
89 overflows++;
90
91 if (overflows > 10) {
92 /*
93 * This should be executed only once during
94 * this test, if we are here for the 10th
95 * time, consider this the recursive issue.
96 *
97 * We can get out of here by disable events,
98 * so no new SIGIO is delivered.
99 */
100 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
101 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
102 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
103 }
104}
105
106static int __event(bool is_x, void *addr, int sig)
107{
108 struct perf_event_attr pe;
109 int fd;
110
111 memset(&pe, 0, sizeof(struct perf_event_attr));
112 pe.type = PERF_TYPE_BREAKPOINT;
113 pe.size = sizeof(struct perf_event_attr);
114
115 pe.config = 0;
116 pe.bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
117 pe.bp_addr = (unsigned long) addr;
118 pe.bp_len = sizeof(long);
119
120 pe.sample_period = 1;
121 pe.sample_type = PERF_SAMPLE_IP;
122 pe.wakeup_events = 1;
123
124 pe.disabled = 1;
125 pe.exclude_kernel = 1;
126 pe.exclude_hv = 1;
127
128 fd = sys_perf_event_open(&pe, 0, -1, -1,
129 perf_event_open_cloexec_flag());
130 if (fd < 0) {
131 pr_debug("failed opening event %llx\n", pe.config);
132 return TEST_FAIL;
133 }
134
135 fcntl(fd, F_SETFL, O_RDWR|O_NONBLOCK|O_ASYNC);
136 fcntl(fd, F_SETSIG, sig);
137 fcntl(fd, F_SETOWN, getpid());
138
139 ioctl(fd, PERF_EVENT_IOC_RESET, 0);
140
141 return fd;
142}
143
144static int bp_event(void *addr, int sig)
145{
146 return __event(true, addr, sig);
147}
148
149static int wp_event(void *addr, int sig)
150{
151 return __event(false, addr, sig);
152}
153
154static long long bp_count(int fd)
155{
156 long long count;
157 int ret;
158
159 ret = read(fd, &count, sizeof(long long));
160 if (ret != sizeof(long long)) {
161 pr_debug("failed to read: %d\n", ret);
162 return TEST_FAIL;
163 }
164
165 return count;
166}
167
168int test__bp_signal(struct test *test __maybe_unused, int subtest __maybe_unused)
169{
170 struct sigaction sa;
171 long long count1, count2, count3;
172
173 /* setup SIGIO signal handler */
174 memset(&sa, 0, sizeof(struct sigaction));
175 sa.sa_sigaction = (void *) sig_handler;
176 sa.sa_flags = SA_SIGINFO;
177
178 if (sigaction(SIGIO, &sa, NULL) < 0) {
179 pr_debug("failed setting up signal handler\n");
180 return TEST_FAIL;
181 }
182
183 sa.sa_sigaction = (void *) sig_handler_2;
184 if (sigaction(SIGUSR1, &sa, NULL) < 0) {
185 pr_debug("failed setting up signal handler 2\n");
186 return TEST_FAIL;
187 }
188
189 /*
190 * We create following events:
191 *
192 * fd1 - breakpoint event on __test_function with SIGIO
193 * signal configured. We should get signal
194 * notification each time the breakpoint is hit
195 *
196 * fd2 - breakpoint event on sig_handler with SIGUSR1
197 * configured. We should get SIGUSR1 each time when
198 * breakpoint is hit
199 *
200 * fd3 - watchpoint event on __test_function with SIGIO
201 * configured.
202 *
203 * Following processing should happen:
204 * Exec: Action: Result:
205 * incq (%rdi) - fd1 event breakpoint hit -> count1 == 1
206 * - SIGIO is delivered
207 * sig_handler - fd2 event breakpoint hit -> count2 == 1
208 * - SIGUSR1 is delivered
209 * sig_handler_2 -> overflows_2 == 1 (nested signal)
210 * sys_rt_sigreturn - return from sig_handler_2
211 * overflows++ -> overflows = 1
212 * sys_rt_sigreturn - return from sig_handler
213 * incq (%rdi) - fd3 event watchpoint hit -> count3 == 1 (wp and bp in one insn)
214 * - SIGIO is delivered
215 * sig_handler - fd2 event breakpoint hit -> count2 == 2
216 * - SIGUSR1 is delivered
217 * sig_handler_2 -> overflows_2 == 2 (nested signal)
218 * sys_rt_sigreturn - return from sig_handler_2
219 * overflows++ -> overflows = 2
220 * sys_rt_sigreturn - return from sig_handler
221 * the_var++ - fd3 event watchpoint hit -> count3 == 2 (standalone watchpoint)
222 * - SIGIO is delivered
223 * sig_handler - fd2 event breakpoint hit -> count2 == 3
224 * - SIGUSR1 is delivered
225 * sig_handler_2 -> overflows_2 == 3 (nested signal)
226 * sys_rt_sigreturn - return from sig_handler_2
227 * overflows++ -> overflows == 3
228 * sys_rt_sigreturn - return from sig_handler
229 *
230 * The test case check following error conditions:
231 * - we get stuck in signal handler because of debug
232 * exception being triggered receursively due to
233 * the wrong RF EFLAG management
234 *
235 * - we never trigger the sig_handler breakpoint due
236 * to the rong RF EFLAG management
237 *
238 */
239
240 fd1 = bp_event(__test_function, SIGIO);
241 fd2 = bp_event(sig_handler, SIGUSR1);
242 fd3 = wp_event((void *)&the_var, SIGIO);
243
244 ioctl(fd1, PERF_EVENT_IOC_ENABLE, 0);
245 ioctl(fd2, PERF_EVENT_IOC_ENABLE, 0);
246 ioctl(fd3, PERF_EVENT_IOC_ENABLE, 0);
247
248 /*
249 * Kick off the test by trigering 'fd1'
250 * breakpoint.
251 */
252 test_function();
253
254 ioctl(fd1, PERF_EVENT_IOC_DISABLE, 0);
255 ioctl(fd2, PERF_EVENT_IOC_DISABLE, 0);
256 ioctl(fd3, PERF_EVENT_IOC_DISABLE, 0);
257
258 count1 = bp_count(fd1);
259 count2 = bp_count(fd2);
260 count3 = bp_count(fd3);
261
262 close(fd1);
263 close(fd2);
264 close(fd3);
265
266 pr_debug("count1 %lld, count2 %lld, count3 %lld, overflow %d, overflows_2 %d\n",
267 count1, count2, count3, overflows, overflows_2);
268
269 if (count1 != 1) {
270 if (count1 == 11)
271 pr_debug("failed: RF EFLAG recursion issue detected\n");
272 else
273 pr_debug("failed: wrong count for bp1%lld\n", count1);
274 }
275
276 if (overflows != 3)
277 pr_debug("failed: wrong overflow hit\n");
278
279 if (overflows_2 != 3)
280 pr_debug("failed: wrong overflow_2 hit\n");
281
282 if (count2 != 3)
283 pr_debug("failed: wrong count for bp2\n");
284
285 if (count3 != 2)
286 pr_debug("failed: wrong count for bp3\n");
287
288 return count1 == 1 && overflows == 3 && count2 == 3 && overflows_2 == 3 && count3 == 2 ?
289 TEST_OK : TEST_FAIL;
290}
291
292bool test__bp_signal_is_supported(void)
293{
294/*
295 * The powerpc so far does not have support to even create
296 * instruction breakpoint using the perf event interface.
297 * Once it's there we can release this.
298 */
299#if defined(__powerpc__) || defined(__s390x__)
300 return false;
301#else
302 return true;
303#endif
304}