tools/testing/selftests/vDSO/vdso_test_getcpu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * vdso_test_getcpu.c: Sample code to test parse_vdso.c and vDSO getcpu()
   4  *
   5  * Copyright (c) 2020 Arm Ltd
   6  */
   7
   8 #include <stdint.h>
   9 #include <elf.h>
  10 #include <stdio.h>
  11 #include <sys/auxv.h>
  12 #include <sys/time.h>
  13
  14 #include "../kselftest.h"
  15 #include "parse_vdso.h"
  16
  17 const char *version = "LINUX_2.6";
  18 const char *name = "__vdso_getcpu";
  19
  20 struct getcpu_cache;
  21 typedef long (*getcpu_t)(unsigned int *, unsigned int *,
  22                          struct getcpu_cache *);
  23
  24 int main(int argc, char **argv)
  25 {
  26         unsigned long sysinfo_ehdr;
  27         unsigned int cpu, node;
  28         getcpu_t get_cpu;
  29         long ret;
  30
  31         sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
  32         if (!sysinfo_ehdr) {
  33                 printf("AT_SYSINFO_EHDR is not present!\n");
  34                 return KSFT_SKIP;
  35         }
  36
  37         vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
  38
  39         get_cpu = (getcpu_t)vdso_sym(version, name);
  40         if (!get_cpu) {
  41                 printf("Could not find %s\n", name);
  42                 return KSFT_SKIP;
  43         }
  44
  45         ret = get_cpu(&cpu, &node, 0);
  46         if (ret == 0) {
  47                 printf("Running on CPU %u node %u\n", cpu, node);
  48         } else {
  49                 printf("%s failed\n", name);
  50                 return KSFT_FAIL;
  51         }
  52
  53         return 0;
  54 }