1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * vdso_test_gettimeofday.c: Sample code to test parse_vdso.c and 4 * vDSO gettimeofday() 5 * Copyright (c) 2014 Andy Lutomirski 6 * 7 * Compile with: 8 * gcc -std=gnu99 vdso_test_gettimeofday.c parse_vdso_gettimeofday.c 9 * 10 * Tested on x86, 32-bit and 64-bit. It may work on other architectures, too. 11 */ 12 13 #include <stdint.h> 14 #include <elf.h> 15 #include <stdio.h> 16 #include <sys/auxv.h> 17 #include <sys/time.h> 18 19 #include "../kselftest.h" 20 #include "parse_vdso.h" 21 22 /* 23 * ARM64's vDSO exports its gettimeofday() implementation with a different 24 * name and version from other architectures, so we need to handle it as 25 * a special case. 26 */ 27 #if defined(__aarch64__) 28 const char *version = "LINUX_2.6.39"; 29 const char *name = "__kernel_gettimeofday"; 30 #elif defined(__riscv) 31 const char *version = "LINUX_4.15"; 32 const char *name = "__vdso_gettimeofday"; 33 #else 34 const char *version = "LINUX_2.6"; 35 const char *name = "__vdso_gettimeofday"; 36 #endif 37 38 int main(int argc, char **argv) 39 { 40 unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR); 41 if (!sysinfo_ehdr) { 42 printf("AT_SYSINFO_EHDR is not present!\n"); 43 return KSFT_SKIP; 44 } 45 46 vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR)); 47 48 /* Find gettimeofday. */ 49 typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz); 50 gtod_t gtod = (gtod_t)vdso_sym(version, name); 51 52 if (!gtod) { 53 printf("Could not find %s\n", name); 54 return KSFT_SKIP; 55 } 56 57 struct timeval tv; 58 long ret = gtod(&tv, 0); 59 60 if (ret == 0) { 61 printf("The time is %lld.%06lld\n", 62 (long long)tv.tv_sec, (long long)tv.tv_usec); 63 } else { 64 printf("%s failed\n", name); 65 return KSFT_FAIL; 66 } 67 68 return 0; 69 } 70