1 /*
2 * Copyright 2014, Michael Ellerman, IBM Corp.
3 * Licensed under GPLv2.
4 */
5
6 #define _GNU_SOURCE /* For CPU_ZERO etc. */
7
8 #include <errno.h>
9 #include <sched.h>
10 #include <setjmp.h>
11 #include <stdlib.h>
12 #include <sys/wait.h>
13
14 #include "utils.h"
15 #include "lib.h"
16
17
pick_online_cpu(void)18 int pick_online_cpu(void)
19 {
20 cpu_set_t mask;
21 int cpu;
22
23 CPU_ZERO(&mask);
24
25 if (sched_getaffinity(0, sizeof(mask), &mask)) {
26 perror("sched_getaffinity");
27 return -1;
28 }
29
30 /* We prefer a primary thread, but skip 0 */
31 for (cpu = 8; cpu < CPU_SETSIZE; cpu += 8)
32 if (CPU_ISSET(cpu, &mask))
33 return cpu;
34
35 /* Search for anything, but in reverse */
36 for (cpu = CPU_SETSIZE - 1; cpu >= 0; cpu--)
37 if (CPU_ISSET(cpu, &mask))
38 return cpu;
39
40 printf("No cpus in affinity mask?!\n");
41 return -1;
42 }
43
bind_to_cpu(int cpu)44 int bind_to_cpu(int cpu)
45 {
46 cpu_set_t mask;
47
48 printf("Binding to cpu %d\n", cpu);
49
50 CPU_ZERO(&mask);
51 CPU_SET(cpu, &mask);
52
53 return sched_setaffinity(0, sizeof(mask), &mask);
54 }
55
56 #define PARENT_TOKEN 0xAA
57 #define CHILD_TOKEN 0x55
58
sync_with_child(union pipe read_pipe,union pipe write_pipe)59 int sync_with_child(union pipe read_pipe, union pipe write_pipe)
60 {
61 char c = PARENT_TOKEN;
62
63 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
64 FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
65 if (c != CHILD_TOKEN) /* sometimes expected */
66 return 1;
67
68 return 0;
69 }
70
wait_for_parent(union pipe read_pipe)71 int wait_for_parent(union pipe read_pipe)
72 {
73 char c;
74
75 FAIL_IF(read(read_pipe.read_fd, &c, 1) != 1);
76 FAIL_IF(c != PARENT_TOKEN);
77
78 return 0;
79 }
80
notify_parent(union pipe write_pipe)81 int notify_parent(union pipe write_pipe)
82 {
83 char c = CHILD_TOKEN;
84
85 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
86
87 return 0;
88 }
89
notify_parent_of_error(union pipe write_pipe)90 int notify_parent_of_error(union pipe write_pipe)
91 {
92 char c = ~CHILD_TOKEN;
93
94 FAIL_IF(write(write_pipe.write_fd, &c, 1) != 1);
95
96 return 0;
97 }
98
wait_for_child(pid_t child_pid)99 int wait_for_child(pid_t child_pid)
100 {
101 int rc;
102
103 if (waitpid(child_pid, &rc, 0) == -1) {
104 perror("waitpid");
105 return 1;
106 }
107
108 if (WIFEXITED(rc))
109 rc = WEXITSTATUS(rc);
110 else
111 rc = 1; /* Signal or other */
112
113 return rc;
114 }
115
kill_child_and_wait(pid_t child_pid)116 int kill_child_and_wait(pid_t child_pid)
117 {
118 kill(child_pid, SIGTERM);
119
120 return wait_for_child(child_pid);
121 }
122
eat_cpu_child(union pipe read_pipe,union pipe write_pipe)123 static int eat_cpu_child(union pipe read_pipe, union pipe write_pipe)
124 {
125 volatile int i = 0;
126
127 /*
128 * We are just here to eat cpu and die. So make sure we can be killed,
129 * and also don't do any custom SIGTERM handling.
130 */
131 signal(SIGTERM, SIG_DFL);
132
133 notify_parent(write_pipe);
134 wait_for_parent(read_pipe);
135
136 /* Soak up cpu forever */
137 while (1) i++;
138
139 return 0;
140 }
141
eat_cpu(int (test_function)(void))142 pid_t eat_cpu(int (test_function)(void))
143 {
144 union pipe read_pipe, write_pipe;
145 int cpu, rc;
146 pid_t pid;
147
148 cpu = pick_online_cpu();
149 FAIL_IF(cpu < 0);
150 FAIL_IF(bind_to_cpu(cpu));
151
152 if (pipe(read_pipe.fds) == -1)
153 return -1;
154
155 if (pipe(write_pipe.fds) == -1)
156 return -1;
157
158 pid = fork();
159 if (pid == 0)
160 exit(eat_cpu_child(write_pipe, read_pipe));
161
162 if (sync_with_child(read_pipe, write_pipe)) {
163 rc = -1;
164 goto out;
165 }
166
167 printf("main test running as pid %d\n", getpid());
168
169 rc = test_function();
170 out:
171 kill(pid, SIGKILL);
172
173 return rc;
174 }
175
176 struct addr_range libc, vdso;
177
parse_proc_maps(void)178 int parse_proc_maps(void)
179 {
180 unsigned long start, end;
181 char execute, name[128];
182 FILE *f;
183 int rc;
184
185 f = fopen("/proc/self/maps", "r");
186 if (!f) {
187 perror("fopen");
188 return -1;
189 }
190
191 do {
192 /* This skips line with no executable which is what we want */
193 rc = fscanf(f, "%lx-%lx %*c%*c%c%*c %*x %*d:%*d %*d %127s\n",
194 &start, &end, &execute, name);
195 if (rc <= 0)
196 break;
197
198 if (execute != 'x')
199 continue;
200
201 if (strstr(name, "libc")) {
202 libc.first = start;
203 libc.last = end - 1;
204 } else if (strstr(name, "[vdso]")) {
205 vdso.first = start;
206 vdso.last = end - 1;
207 }
208 } while(1);
209
210 fclose(f);
211
212 return 0;
213 }
214
215 #define PARANOID_PATH "/proc/sys/kernel/perf_event_paranoid"
216
require_paranoia_below(int level)217 bool require_paranoia_below(int level)
218 {
219 unsigned long current;
220 char *end, buf[16];
221 FILE *f;
222 int rc;
223
224 rc = -1;
225
226 f = fopen(PARANOID_PATH, "r");
227 if (!f) {
228 perror("fopen");
229 goto out;
230 }
231
232 if (!fgets(buf, sizeof(buf), f)) {
233 printf("Couldn't read " PARANOID_PATH "?\n");
234 goto out_close;
235 }
236
237 current = strtoul(buf, &end, 10);
238
239 if (end == buf) {
240 printf("Couldn't parse " PARANOID_PATH "?\n");
241 goto out_close;
242 }
243
244 if (current >= level)
245 goto out;
246
247 rc = 0;
248 out_close:
249 fclose(f);
250 out:
251 return rc;
252 }
253
254