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 close(fd_wp);
108 }
109
110 for (i = 0; i < wp_cnt; i++)
111 close(fd[i]);
112
113 return 0;
114 }
115
detect_cnt(bool is_x)116 static int detect_cnt(bool is_x)
117 {
118 struct perf_event_attr attr;
119 void *addr = is_x ? (void *)test_function : (void *)&the_var;
120 int fd[100], cnt = 0, i;
121
122 while (1) {
123 if (cnt == 100) {
124 pr_debug("way too many debug registers, fix the test\n");
125 return 0;
126 }
127 fd[cnt] = __event(is_x, addr, &attr);
128
129 if (fd[cnt] < 0)
130 break;
131 cnt++;
132 }
133
134 for (i = 0; i < cnt; i++)
135 close(fd[i]);
136
137 return cnt;
138 }
139
detect_ioctl(void)140 static int detect_ioctl(void)
141 {
142 struct perf_event_attr attr;
143 int fd, ret = 1;
144
145 fd = wp_event((void *) &the_var, &attr);
146 if (fd > 0) {
147 ret = ioctl(fd, PERF_EVENT_IOC_MODIFY_ATTRIBUTES, &attr);
148 close(fd);
149 }
150
151 return ret ? 0 : 1;
152 }
153
detect_share(int wp_cnt,int bp_cnt)154 static int detect_share(int wp_cnt, int bp_cnt)
155 {
156 struct perf_event_attr attr;
157 int i, *fd = NULL, ret = -1;
158
159 if (wp_cnt + bp_cnt == 0)
160 return 0;
161
162 fd = malloc(sizeof(int) * (wp_cnt + bp_cnt));
163 if (!fd)
164 return -1;
165
166 for (i = 0; i < wp_cnt; i++) {
167 fd[i] = wp_event((void *)&the_var, &attr);
168 if (fd[i] == -1) {
169 pr_err("failed to create wp\n");
170 goto out;
171 }
172 }
173
174 for (; i < (bp_cnt + wp_cnt); i++) {
175 fd[i] = bp_event((void *)test_function, &attr);
176 if (fd[i] == -1)
177 break;
178 }
179
180 ret = i != (bp_cnt + wp_cnt);
181
182 out:
183 while (i--)
184 close(fd[i]);
185
186 free(fd);
187 return ret;
188 }
189
190 /*
191 * This test does following:
192 * - detects the number of watch/break-points,
193 * skip test if any is missing
194 * - detects PERF_EVENT_IOC_MODIFY_ATTRIBUTES ioctl,
195 * skip test if it's missing
196 * - detects if watchpoints and breakpoints share
197 * same slots
198 * - create all possible watchpoints on cpu 0
199 * - change one of it to breakpoint
200 * - in case wp and bp do not share slots,
201 * we create another watchpoint to ensure
202 * the slot accounting is correct
203 */
test__bp_accounting(struct test_suite * test __maybe_unused,int subtest __maybe_unused)204 static int test__bp_accounting(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
205 {
206 int has_ioctl = detect_ioctl();
207 int wp_cnt = detect_cnt(false);
208 int bp_cnt = detect_cnt(true);
209 int share = detect_share(wp_cnt, bp_cnt);
210
211 if (!BP_ACCOUNT_IS_SUPPORTED) {
212 pr_debug("Test not supported on this architecture");
213 return TEST_SKIP;
214 }
215
216 pr_debug("watchpoints count %d, breakpoints count %d, has_ioctl %d, share %d\n",
217 wp_cnt, bp_cnt, has_ioctl, share);
218
219 if (!wp_cnt || !bp_cnt || !has_ioctl)
220 return TEST_SKIP;
221
222 return bp_accounting(wp_cnt, share);
223 }
224
225 DEFINE_SUITE("Breakpoint accounting", bp_accounting);
226