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