xref: /openbmc/linux/tools/perf/tests/bp_account.c (revision 93f5715e)
1 /*
2  * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
3  * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
4  */
5 #define __SANE_USERSPACE_TYPES__
6 
7 #include <stdlib.h>
8 #include <stdio.h>
9 #include <unistd.h>
10 #include <string.h>
11 #include <sys/ioctl.h>
12 #include <time.h>
13 #include <fcntl.h>
14 #include <signal.h>
15 #include <sys/mman.h>
16 #include <linux/compiler.h>
17 #include <linux/hw_breakpoint.h>
18 #include <sys/ioctl.h>
19 
20 #include "tests.h"
21 #include "debug.h"
22 #include "perf.h"
23 #include "cloexec.h"
24 
25 volatile long the_var;
26 
27 static noinline int test_function(void)
28 {
29 	return 0;
30 }
31 
32 static int __event(bool is_x, void *addr, struct perf_event_attr *attr)
33 {
34 	int fd;
35 
36 	memset(attr, 0, sizeof(struct perf_event_attr));
37 	attr->type = PERF_TYPE_BREAKPOINT;
38 	attr->size = sizeof(struct perf_event_attr);
39 
40 	attr->config = 0;
41 	attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
42 	attr->bp_addr = (unsigned long) addr;
43 	attr->bp_len = sizeof(long);
44 
45 	attr->sample_period = 1;
46 	attr->sample_type = PERF_SAMPLE_IP;
47 
48 	attr->exclude_kernel = 1;
49 	attr->exclude_hv = 1;
50 
51 	fd = sys_perf_event_open(attr, -1, 0, -1,
52 				 perf_event_open_cloexec_flag());
53 	if (fd < 0) {
54 		pr_debug("failed opening event %llx\n", attr->config);
55 		return TEST_FAIL;
56 	}
57 
58 	return fd;
59 }
60 
61 static int wp_event(void *addr, struct perf_event_attr *attr)
62 {
63 	return __event(false, addr, attr);
64 }
65 
66 static int bp_event(void *addr, struct perf_event_attr *attr)
67 {
68 	return __event(true, addr, attr);
69 }
70 
71 static int bp_accounting(int wp_cnt, int share)
72 {
73 	struct perf_event_attr attr, attr_mod, attr_new;
74 	int i, fd[wp_cnt], fd_wp, ret;
75 
76 	for (i = 0; i < wp_cnt; i++) {
77 		fd[i] = wp_event((void *)&the_var, &attr);
78 		TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
79 		pr_debug("wp %d created\n", i);
80 	}
81 
82 	attr_mod = attr;
83 	attr_mod.bp_type = HW_BREAKPOINT_X;
84 	attr_mod.bp_addr = (unsigned long) test_function;
85 
86 	ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);
87 	TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);
88 
89 	pr_debug("wp 0 modified to bp\n");
90 
91 	if (!share) {
92 		fd_wp = wp_event((void *)&the_var, &attr_new);
93 		TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);
94 		pr_debug("wp max created\n");
95 	}
96 
97 	for (i = 0; i < wp_cnt; i++)
98 		close(fd[i]);
99 
100 	return 0;
101 }
102 
103 static int detect_cnt(bool is_x)
104 {
105 	struct perf_event_attr attr;
106 	void *addr = is_x ? (void *)test_function : (void *)&the_var;
107 	int fd[100], cnt = 0, i;
108 
109 	while (1) {
110 		if (cnt == 100) {
111 			pr_debug("way too many debug registers, fix the test\n");
112 			return 0;
113 		}
114 		fd[cnt] = __event(is_x, addr, &attr);
115 
116 		if (fd[cnt] < 0)
117 			break;
118 		cnt++;
119 	}
120 
121 	for (i = 0; i < cnt; i++)
122 		close(fd[i]);
123 
124 	return cnt;
125 }
126 
127 static int detect_ioctl(void)
128 {
129 	struct perf_event_attr attr;
130 	int fd, ret = 1;
131 
132 	fd = wp_event((void *) &the_var, &attr);
133 	if (fd > 0) {
134 		ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
135 		close(fd);
136 	}
137 
138 	return ret ? 0 : 1;
139 }
140 
141 static int detect_share(int wp_cnt, int bp_cnt)
142 {
143 	struct perf_event_attr attr;
144 	int i, fd[wp_cnt + bp_cnt], ret;
145 
146 	for (i = 0; i < wp_cnt; i++) {
147 		fd[i] = wp_event((void *)&the_var, &attr);
148 		TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
149 	}
150 
151 	for (; i < (bp_cnt + wp_cnt); i++) {
152 		fd[i] = bp_event((void *)test_function, &attr);
153 		if (fd[i] == -1)
154 			break;
155 	}
156 
157 	ret = i != (bp_cnt + wp_cnt);
158 
159 	while (i--)
160 		close(fd[i]);
161 
162 	return ret;
163 }
164 
165 /*
166  * This test does following:
167  *   - detects the number of watch/break-points,
168  *     skip test if any is missing
169  *   - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
170  *     skip test if it's missing
171  *   - detects if watchpoints and breakpoints share
172  *     same slots
173  *   - create all possible watchpoints on cpu 0
174  *   - change one of it to breakpoint
175  *   - in case wp and bp do not share slots,
176  *     we create another watchpoint to ensure
177  *     the slot accounting is correct
178  */
179 int test__bp_accounting(struct test *test __maybe_unused, int subtest __maybe_unused)
180 {
181 	int has_ioctl = detect_ioctl();
182 	int wp_cnt = detect_cnt(false);
183 	int bp_cnt = detect_cnt(true);
184 	int share  = detect_share(wp_cnt, bp_cnt);
185 
186 	pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
187 		 wp_cnt, bp_cnt, has_ioctl, share);
188 
189 	if (!wp_cnt || !bp_cnt || !has_ioctl)
190 		return TEST_SKIP;
191 
192 	return bp_accounting(wp_cnt, share);
193 }
194