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