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sysdeps/clock_gettime: Use clock_gettime64 if avaliable

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With the clock_gettime64 call we prefer to use vDSO. There is no call
to clock_gettime64 on glibc with older headers and kernel 5.1+ if it
doesn't support vDSO.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This commit is contained in:
Alistair Francis 2019-07-15 16:30:59 -07:00
parent f6fbce7dd7
commit ec138c67cb
2 changed files with 46 additions and 1 deletions
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3
include/time.h
View File

@ -211,11 +211,14 @@ extern double __difftime (time_t time1, time_t time0);
#if __TIMESIZE == 64
# define __clock_nanosleep_time64 __clock_nanosleep
# define __clock_gettime64 __clock_gettime
#else
extern int __clock_nanosleep_time64 (clockid_t clock_id,
int flags, const struct __timespec64 *req,
struct __timespec64 *rem);
libc_hidden_proto (__clock_nanosleep_time64)
extern int __clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp);
libc_hidden_proto (__clock_gettime64)
#endif
/* Use in the clock_* functions. Size of the field representing the

44
sysdeps/unix/sysv/linux/clock_gettime.c
View File

@ -17,6 +17,7 @@
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <kernel-features.h>
#include <errno.h>
#include <time.h>
#include "kernel-posix-cpu-timers.h"
@ -30,10 +31,51 @@
/* Get current value of CLOCK and store it in TP. */
int
__clock_gettime64 (clockid_t clock_id, struct __timespec64 *tp)
{
#ifdef __ASSUME_TIME64_SYSCALLS
# ifndef __NR_clock_gettime64
# define __NR_clock_gettime64 __NR_clock_gettime
# define __vdso_clock_gettime64 __vdso_clock_gettime
# endif
return INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
#else
# if defined HAVE_CLOCK_GETTIME64_VSYSCALL
int ret64 = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
if (ret64 == 0 || errno != ENOSYS)
return ret64;
# endif
struct timespec tp32;
int ret = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &tp32);
if (ret == 0)
*tp = valid_timespec_to_timespec64 (tp32);
return ret;
#endif
}
#if __TIMESIZE != 64
int
__clock_gettime (clockid_t clock_id, struct timespec *tp)
{
return INLINE_VSYSCALL (clock_gettime, 2, clock_id, tp);
int ret;
struct __timespec64 tp64;
ret = __clock_gettime64 (clock_id, &tp64);
if (ret == 0)
{
if (! in_time_t_range (tp64.tv_sec))
{
__set_errno (EOVERFLOW);
return -1;
}
*tp = valid_timespec64_to_timespec (tp64);
}
return ret;
}
#endif
libc_hidden_def (__clock_gettime)
versioned_symbol (libc, __clock_gettime, clock_gettime, GLIBC_2_17);