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
22static volatile long the_var;
23
24static noinline int test_function(void)
25{
26	return 0;
27}
28
29static 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
58static int wp_event(void *addr, struct perf_event_attr *attr)
59{
60	return __event(false, addr, attr);
61}
62
63static int bp_event(void *addr, struct perf_event_attr *attr)
64{
65	return __event(true, addr, attr);
66}
67
68static 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
100static 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
124static 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
138static 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 */
176int 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
192bool 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