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 | |
37 | static noinline int test_function(void) |
38 | { |
39 | return 0; |
40 | } |
41 | |
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, pid: -1, cpu: 0, group_fd: -1, |
62 | flags: 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 | |
71 | static int wp_event(void *addr, struct perf_event_attr *attr) |
72 | { |
73 | return __event(is_x: false, addr, attr); |
74 | } |
75 | |
76 | static int bp_event(void *addr, struct perf_event_attr *attr) |
77 | { |
78 | return __event(is_x: true, addr, attr); |
79 | } |
80 | |
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(addr: (void *)&the_var, attr: &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(addr: (void *)&the_var, attr: &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 | |
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: &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 | |
137 | static int detect_ioctl(void) |
138 | { |
139 | struct perf_event_attr attr; |
140 | int fd, ret = 1; |
141 | |
142 | fd = wp_event(addr: (void *) &the_var, attr: &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 | |
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(addr: (void *)&the_var, attr: &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(addr: (void *)test_function, attr: &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 | */ |
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(is_x: false); |
205 | int bp_cnt = detect_cnt(is_x: 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 | |