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