1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Powerpc needs __SANE_USERSPACE_TYPES__ before <linux/types.h> to select
4 * 'int-ll64.h' and avoid compile warnings when printing __u64 with %llu.
5 */
6 #define __SANE_USERSPACE_TYPES__
7
8 #include <stdlib.h>
9 #include <stdio.h>
10 #include <unistd.h>
11 #include <string.h>
12 #include <sys/ioctl.h>
13 #include <fcntl.h>
14 #include <linux/hw_breakpoint.h>
15
16 #include "tests.h"
17 #include "debug.h"
18 #include "event.h"
19 #include "parse-events.h"
20 #include "../perf-sys.h"
21 #include "cloexec.h"
22
23 /*
24 * PowerPC and S390 do not support creation of instruction breakpoints using the
25 * perf_event interface.
26 *
27 * Just disable the test for these architectures until these issues are
28 * resolved.
29 */
30 #if defined(__powerpc__) || defined(__s390x__)
31 #define BP_ACCOUNT_IS_SUPPORTED 0
32 #else
33 #define BP_ACCOUNT_IS_SUPPORTED 1
34 #endif
35
36 static volatile long the_var;
37
test_function(void)38 static noinline int test_function(void)
39 {
40 return 0;
41 }
42
__event(bool is_x,void * addr,struct perf_event_attr * attr)43 static int __event(bool is_x, void *addr, struct perf_event_attr *attr)
44 {
45 int fd;
46
47 memset(attr, 0, sizeof(struct perf_event_attr));
48 attr->type = PERF_TYPE_BREAKPOINT;
49 attr->size = sizeof(struct perf_event_attr);
50
51 attr->config = 0;
52 attr->bp_type = is_x ? HW_BREAKPOINT_X : HW_BREAKPOINT_W;
53 attr->bp_addr = (unsigned long) addr;
54 attr->bp_len = is_x ? default_breakpoint_len() : sizeof(long);
55
56 attr->sample_period = 1;
57 attr->sample_type = PERF_SAMPLE_IP;
58
59 attr->exclude_kernel = 1;
60 attr->exclude_hv = 1;
61
62 fd = sys_perf_event_open(attr, -1, 0, -1,
63 perf_event_open_cloexec_flag());
64 if (fd < 0) {
65 pr_debug("failed opening event %llx\n", attr->config);
66 return TEST_FAIL;
67 }
68
69 return fd;
70 }
71
wp_event(void * addr,struct perf_event_attr * attr)72 static int wp_event(void *addr, struct perf_event_attr *attr)
73 {
74 return __event(false, addr, attr);
75 }
76
bp_event(void * addr,struct perf_event_attr * attr)77 static int bp_event(void *addr, struct perf_event_attr *attr)
78 {
79 return __event(true, addr, attr);
80 }
81
bp_accounting(int wp_cnt,int share)82 static int bp_accounting(int wp_cnt, int share)
83 {
84 struct perf_event_attr attr, attr_mod, attr_new;
85 int i, fd[wp_cnt], fd_wp, ret;
86
87 for (i = 0; i < wp_cnt; i++) {
88 fd[i] = wp_event((void *)&the_var, &attr);
89 TEST_ASSERT_VAL("failed to create wp\n", fd[i] != -1);
90 pr_debug("wp %d created\n", i);
91 }
92
93 attr_mod = attr;
94 attr_mod.bp_type = HW_BREAKPOINT_X;
95 attr_mod.bp_addr = (unsigned long) test_function;
96 attr_mod.bp_len = default_breakpoint_len();
97
98 ret = ioctl(fd[0], PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr_mod);
99 TEST_ASSERT_VAL("failed to modify wp\n", ret == 0);
100
101 pr_debug("wp 0 modified to bp\n");
102
103 if (!share) {
104 fd_wp = wp_event((void *)&the_var, &attr_new);
105 TEST_ASSERT_VAL("failed to create max wp\n", fd_wp != -1);
106 pr_debug("wp max created\n");
107 }
108
109 for (i = 0; i < wp_cnt; i++)
110 close(fd[i]);
111
112 return 0;
113 }
114
detect_cnt(bool is_x)115 static int detect_cnt(bool is_x)
116 {
117 struct perf_event_attr attr;
118 void *addr = is_x ? (void *)test_function : (void *)&the_var;
119 int fd[100], cnt = 0, i;
120
121 while (1) {
122 if (cnt == 100) {
123 pr_debug("way too many debug registers, fix the test\n");
124 return 0;
125 }
126 fd[cnt] = __event(is_x, addr, &attr);
127
128 if (fd[cnt] < 0)
129 break;
130 cnt++;
131 }
132
133 for (i = 0; i < cnt; i++)
134 close(fd[i]);
135
136 return cnt;
137 }
138
detect_ioctl(void)139 static int detect_ioctl(void)
140 {
141 struct perf_event_attr attr;
142 int fd, ret = 1;
143
144 fd = wp_event((void *) &the_var, &attr);
145 if (fd > 0) {
146 ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
147 close(fd);
148 }
149
150 return ret ? 0 : 1;
151 }
152
detect_share(int wp_cnt,int bp_cnt)153 static int detect_share(int wp_cnt, int bp_cnt)
154 {
155 struct perf_event_attr attr;
156 int i, *fd = NULL, ret = -1;
157
158 if (wp_cnt + bp_cnt == 0)
159 return 0;
160
161 fd = malloc(sizeof(int) * (wp_cnt + bp_cnt));
162 if (!fd)
163 return -1;
164
165 for (i = 0; i < wp_cnt; i++) {
166 fd[i] = wp_event((void *)&the_var, &attr);
167 if (fd[i] == -1) {
168 pr_err("failed to create wp\n");
169 goto out;
170 }
171 }
172
173 for (; i < (bp_cnt + wp_cnt); i++) {
174 fd[i] = bp_event((void *)test_function, &attr);
175 if (fd[i] == -1)
176 break;
177 }
178
179 ret = i != (bp_cnt + wp_cnt);
180
181 out:
182 while (i--)
183 close(fd[i]);
184
185 free(fd);
186 return ret;
187 }
188
189 /*
190 * This test does following:
191 * - detects the number of watch/break-points,
192 * skip test if any is missing
193 * - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
194 * skip test if it's missing
195 * - detects if watchpoints and breakpoints share
196 * same slots
197 * - create all possible watchpoints on cpu 0
198 * - change one of it to breakpoint
199 * - in case wp and bp do not share slots,
200 * we create another watchpoint to ensure
201 * the slot accounting is correct
202 */
test__bp_accounting(struct test_suite * test __maybe_unused,int subtest __maybe_unused)203 static int test__bp_accounting(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
204 {
205 int has_ioctl = detect_ioctl();
206 int wp_cnt = detect_cnt(false);
207 int bp_cnt = detect_cnt(true);
208 int share = detect_share(wp_cnt, bp_cnt);
209
210 if (!BP_ACCOUNT_IS_SUPPORTED) {
211 pr_debug("Test not supported on this architecture");
212 return TEST_SKIP;
213 }
214
215 pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
216 wp_cnt, bp_cnt, has_ioctl, share);
217
218 if (!wp_cnt || !bp_cnt || !has_ioctl)
219 return TEST_SKIP;
220
221 return bp_accounting(wp_cnt, share);
222 }
223
224 DEFINE_SUITE("Breakpoint accounting", bp_accounting);
225