kernel/tools/testing/selftests/powerpc/pmu/lib.c

   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
  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
  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
  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
  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
  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
  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
  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
 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
 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
 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
 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
 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