Currently the vDSO selftests use the time-related types from libc. This works on glibc by chance today but will break with other libc implementations or on distributions which switch to 64-bit times everywhere.
The kernel's UAPI headers provide the proper types to use with the vDSO (and raw syscalls) but are not necessarily compatible with libc types. Introduce a new header which makes the UAPI headers compatible with the libc. Tested with glibc, musl and nolibc. Signed-off-by: Thomas Weißschuh <[email protected]> --- tools/testing/selftests/vDSO/vdso_types.h | 70 +++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/tools/testing/selftests/vDSO/vdso_types.h b/tools/testing/selftests/vDSO/vdso_types.h new file mode 100644 index 0000000000000000000000000000000000000000..a1f2f5412e813d5ba6e57a87e28b9eacc68cccac --- /dev/null +++ b/tools/testing/selftests/vDSO/vdso_types.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2025 Thomas Weißschuh <[email protected]>, Linutronix GmbH + * + * Types to use with vDSO functions. + * + * The types used by the vDSO functions do not necessarily match the ones used + * by libc. The kernel's UAPI headers do provide definitions for those types + * but are often not compatible with libc which applications need to use. + * As the types differ between platforms listing them manually is a lot of work + * and error prone. Instead hack around the incompatibilities of the libc and + * UAPI headers and use the UAPI types. + */ +#ifndef __VDSO_TYPES_H__ +#define __VDSO_TYPES_H__ + +/* + * Include the headers from libc first to not override any of its types later. + */ +#include <time.h> +#include <sys/time.h> + +/* + * Avoid collisions. + */ +#define timeval kernel_timeval_moved +#define itimerspec kernel_itimerspec_moved +#define itimerval kernel_itimerval_moved +#define timezone kernel_timezone_moved + +/* + * Get the UAPI types. + */ +#include <linux/time.h> + +#undef timeval +#undef itimerspec +#undef itimerval +#undef timezone + +/* + * The UAPI headers do not provide their own 'struct __kernel_timezone'. + * 'struct timezone' is the one from libc. + */ +struct kernel_timezone { + int tz_minuteswest; + int tz_dsttime; +}; + +#include <linux/version.h> + +/* + * UAPI headers from the libc may be older and not provide these. + */ +#if KERNEL_VERSION(5, 5, 0) > LINUX_VERSION_CODE +typedef __kernel_long_t __kernel_old_time_t; + +struct __kernel_old_timespec { + __kernel_old_time_t tv_sec; + long tv_nsec; +}; +#endif + +typedef long (*vdso_gettimeofday_t)(struct __kernel_old_timeval *tv, struct kernel_timezone *tz); +typedef long (*vdso_clock_gettime_t)(__kernel_clockid_t clk_id, struct __kernel_old_timespec *ts); +typedef long (*vdso_clock_gettime64_t)(__kernel_clockid_t clk_id, struct __kernel_timespec *ts); +typedef long (*vdso_clock_getres_t)(__kernel_clockid_t clk_id, struct __kernel_old_timespec *ts); +typedef __kernel_time_t (*vdso_time_t)(__kernel_time_t *t); + +#endif /* __VDSO_TYPES_H__ */ -- 2.51.0
