linux/tools/testing/selftests/vDSO/vdso_test_getcpu.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * vdso_test_getcpu.c: Sample code to test parse_vdso.c and vDSO getcpu()
 *
 * Copyright (c) 2020 Arm Ltd
 */

#include <stdint.h>
#include <elf.h>
#include <stdio.h>
#include <sys/auxv.h>
#include <sys/time.h>

#include "../kselftest.h"
#include "parse_vdso.h"
#include "vdso_config.h"
#include "vdso_call.h"

struct getcpu_cache;
typedef long (*getcpu_t)(unsigned int *, unsigned int *,
			 struct getcpu_cache *);

int main(int argc, char **argv)
{
	const char *version = versions[VDSO_VERSION];
	const char **name = (const char **)&names[VDSO_NAMES];
	unsigned long sysinfo_ehdr;
	unsigned int cpu, node;
	getcpu_t get_cpu;
	long ret;

	sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
	if (!sysinfo_ehdr) {
		printf("AT_SYSINFO_EHDR is not present!\n");
		return KSFT_SKIP;
	}

	vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));

	get_cpu = (getcpu_t)vdso_sym(version, name[4]);
	if (!get_cpu) {
		printf("Could not find %s\n", name[4]);
		return KSFT_SKIP;
	}

	ret = VDSO_CALL(get_cpu, 3, &cpu, &node, 0);
	if (ret == 0) {
		printf("Running on CPU %u node %u\n", cpu, node);
	} else {
		printf("%s failed\n", name[4]);
		return KSFT_FAIL;
	}

	return 0;
}