[PATCH 2/2] sysdeps/clock_gettime: Use clock_gettime64 if avaliable

[Lukasz Majewski]

Hi Alistair,

> ---
> This was patch was runtime tested with RV32 and RV64
> It was build tested using the ./scripts/build-many-glibcs.py script.
> 
> I will run:
> $ make ; make install ; make check
> tests on native ARM (32-bit) with the following three confiugrations:
>  - 4.19 Kernel and 4.19 Headers
>  - 5.2 Kernel and 4.19 Headers
>  - 5.2 Kernel and 5.2 Headers
> I should have the results later this week.
> 
>  include/time.h                          |  3 ++
>  sysdeps/unix/sysv/linux/clock_gettime.c | 50
> ++++++++++++++++++++++++- 2 files changed, 52 insertions(+), 1
> deletion(-)
> 
> diff --git a/include/time.h b/include/time.h
> index e0974309726..d4cdfdf38e8 100644
> --- a/include/time.h
> +++ b/include/time.h
> @@ -214,6 +214,7 @@ extern double __difftime (time_t time1, time_t
> time0); # define __clock_nanosleep_time64 __clock_nanosleep
>  # define __nanosleep_time64 __nanosleep
>  # define __nanosleep_nocancel_time64 __nanosleep_nocancel
> +# define __clock_gettime64 __clock_gettime
>  #else
>  extern int __thrd_sleep_time64 (const struct __timespec64*
> time_point, struct __timespec64* remaining);
> @@ -228,6 +229,8 @@ libc_hidden_proto (__nanosleep_time64)
>  extern int __nanosleep_nocancel_time64 (const struct __timespec64
> *requested_time, struct __timespec64 *remaining);
>  libc_hidden_proto (__nanosleep_nocancel_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
> diff --git a/sysdeps/unix/sysv/linux/clock_gettime.c
> b/sysdeps/unix/sysv/linux/clock_gettime.c index
> ca40983f6ca..b2ed3f2b698 100644 ---
> a/sysdeps/unix/sysv/linux/clock_gettime.c +++
> b/sysdeps/unix/sysv/linux/clock_gettime.c @@ -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 +31,57 @@
>  
>  /* 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 __NR_clock_gettime64 && defined
> HAVE_CLOCK_GETTIME64_VSYSCALL
> +  long int ret_64;

Minor comment:

IMHO it would be enough to have 'int ret_64;'

Also, in the commit description it would be worth to mention that with
clock_gettime64 call we prefer to use vDSO (no call to clock_gettime64
on glibc with older headers and kernel 5.1+ if it doesn't support vDSO).

> +  ret_64 = INLINE_VSYSCALL (clock_gettime64, 2, clock_id, tp);
> +
> +  if (ret_64 == 0 || errno != ENOSYS)
> +    return ret_64;
> +# endif /* __NR_clock_gettime64 && HAVE_CLOCK_GETTIME64_VSYSCALL  */
> +  int ret;
> +  struct timespec tp32;
> +
> +  ret = INLINE_VSYSCALL (clock_gettime, 2, clock_id, &tp32);
> +
> +  if (ret == 0 || errno != ENOSYS)
> +    *tp = valid_timespec_to_timespec64 (tp32);
> +
> +  return ret;
> +#endif /* __ASSUME_TIME64_SYSCALLS  */
> +}
> +
> +#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 || errno != ENOSYS)
> +    {
> +      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);


Thanks for preparing the patch :-)


Best regards,

Lukasz Majewski

--

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