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
35static volatile long the_var;
36
37static noinline int test_function(void)
38{
39	return 0;
40}
41
42static 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
71static int wp_event(void *addr, struct perf_event_attr *attr)
72{
73	return __event(false, addr, attr);
74}
75
76static int bp_event(void *addr, struct perf_event_attr *attr)
77{
78	return __event(true, addr, attr);
79}
80
81static 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
113static 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
137static 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
151static 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
179out:
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 */
201static 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
222DEFINE_SUITE("Breakpoint accounting", bp_accounting);
223