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Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/vDSO/vdso_test_gettimeofday.c | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c b/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c new file mode 100644 index 000000000..8ccc73ed8 --- /dev/null +++ b/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * vdso_test_gettimeofday.c: Sample code to test parse_vdso.c and + * vDSO gettimeofday() + * Copyright (c) 2014 Andy Lutomirski + * + * Compile with: + * gcc -std=gnu99 vdso_test_gettimeofday.c parse_vdso_gettimeofday.c + * + * Tested on x86, 32-bit and 64-bit. It may work on other architectures, too. + */ + +#include <stdint.h> +#include <elf.h> +#include <stdio.h> +#include <sys/auxv.h> +#include <sys/time.h> + +#include "../kselftest.h" +#include "parse_vdso.h" + +/* + * ARM64's vDSO exports its gettimeofday() implementation with a different + * name and version from other architectures, so we need to handle it as + * a special case. + */ +#if defined(__aarch64__) +const char *version = "LINUX_2.6.39"; +const char *name = "__kernel_gettimeofday"; +#else +const char *version = "LINUX_2.6"; +const char *name = "__vdso_gettimeofday"; +#endif + +int main(int argc, char **argv) +{ + unsigned long 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)); + + /* Find gettimeofday. */ + typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz); + gtod_t gtod = (gtod_t)vdso_sym(version, name); + + if (!gtod) { + printf("Could not find %s\n", name); + return KSFT_SKIP; + } + + struct timeval tv; + long ret = gtod(&tv, 0); + + if (ret == 0) { + printf("The time is %lld.%06lld\n", + (long long)tv.tv_sec, (long long)tv.tv_usec); + } else { + printf("%s failed\n", name); + return KSFT_FAIL; + } + + return 0; +} |