selftests/vDSO/vdso_test_getcpu.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * vdso_test_getcpu.c: Sample code to test parse_vdso.c and vDSO getcpu()
0004  *
0005  * Copyright (c) 2020 Arm Ltd
0006  */
0007
0008 #include <stdint.h>
0009 #include <elf.h>
0010 #include <stdio.h>
0011 #include <sys/auxv.h>
0012 #include <sys/time.h>
0013
0014 #include "../kselftest.h"
0015 #include "parse_vdso.h"
0016
0017 const char *version = "LINUX_2.6";
0018 const char *name = "__vdso_getcpu";
0019
0020 struct getcpu_cache;
0021 typedef long (*getcpu_t)(unsigned int *, unsigned int *,
0022              struct getcpu_cache *);
0023
0024 int main(int argc, char **argv)
0025 {
0026     unsigned long sysinfo_ehdr;
0027     unsigned int cpu, node;
0028     getcpu_t get_cpu;
0029     long ret;
0030
0031     sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
0032     if (!sysinfo_ehdr) {
0033         printf("AT_SYSINFO_EHDR is not present!\n");
0034         return KSFT_SKIP;
0035     }
0036
0037     vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
0038
0039     get_cpu = (getcpu_t)vdso_sym(version, name);
0040     if (!get_cpu) {
0041         printf("Could not find %s\n", name);
0042         return KSFT_SKIP;
0043     }
0044
0045     ret = get_cpu(&cpu, &node, 0);
0046     if (ret == 0) {
0047         printf("Running on CPU %u node %u\n", cpu, node);
0048     } else {
0049         printf("%s failed\n", name);
0050         return KSFT_FAIL;
0051     }
0052
0053     return 0;
0054 }