[v2,09/11] Use clock_gettime to implement gettimeofday.

Message ID 20191025120832.27667-10-adhemerval.zanella@linaro.org
State Accepted
Commit 5e46749c64d51f50f8511ed99c1266d7c13e182b
Headers show
Series
  • Y2038 preparation: use clock_[gs]ettime to implement the other time-getting and -setting functions.
Related show

Commit Message

Adhemerval Zanella Oct. 25, 2019, 12:08 p.m.
Use clock_gettime to implement gettimeofday

Changes from previous version:

  - Do not remove Linux arch-specific implementations.

--

Consolidate generic gettimeofday implementation to use clock_gettime.
Linux ports that still provide gettimeofday through vDSO are not
changed.

Remove sysdeps/unix/clock_gettime.c, which implemented clock_gettime
using gettimeofday; new OS ports must provide a real implementation of
clock_gettime.

Rename sysdeps/mach/gettimeofday.c to sysdeps/mach/clock_gettime.c and
convert into an implementation of clock_gettime.  It only supports
CLOCK_REALTIME; Mach does not appear to have any support for monotonic
clocks.  It uses __host_get_time, which provides at best microsecond
resolution.  Hurd is currently using sysdeps/posix/clock_getres.c for
clock_getres; its output for CLOCK_REALTIME is based on
sysconf (_SC_CLK_TCK), and I do not know whether that gives the
correct result.

Unlike settimeofday, there are no known uses of gettimeofday's
vestigial "get time zone" feature that are not bugs.  (The per-process
timezone support in localtime and friends is unrelated, and the
programs that set the kernel's offset between the hardware clock and
UTC do not need to read it back.)  Therefore, this feature is dummied
out.  Henceforth, if gettimeofday's "struct timezone" argument is not
NULL, it will write zeroes to both fields.  Any program that is
actually looking at this data will thus think it is running in UTC,
which is probably more correct than whatever it was doing before.

[__]gettimeofday no longer has any internal callers, so we can now
remove its internal prototype and PLT bypass aliases.  The
__gettimeofday@GLIBC_2.0 export remains, in case it is used by any
third-party code.

It also allows to simplify the arch-specific implementation on x86 and
powerpc to remove the hack to disable the internal route to non iFUNC
variant for internal symbol.

This patch also fixes a missing optimization on aarch64, powerpc, and
x86 where the code used on static build do not use the vDSO.

Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,
powerpc64-linux-gnu, powerpc-linux-gnu, and aarch64-linux-gnu.

Co-authored-by: Zack Weinberg <zackw@panix.com>
---
 NEWS                                          | 15 ++++
 include/sys/time.h                            |  2 -
 sysdeps/{unix => mach}/clock_gettime.c        | 37 +++++-----
 sysdeps/mach/gettimeofday.c                   | 43 ------------
 sysdeps/posix/gettimeofday.c                  | 67 ------------------
 sysdeps/unix/syscalls.list                    |  1 -
 .../unix/sysv/linux/aarch64/gettimeofday.c    | 34 ++++-----
 .../sysv/linux/{i386 => alpha}/gettimeofday.c | 25 ++-----
 .../unix/sysv/linux/alpha/osf_gettimeofday.c  | 11 ++-
 sysdeps/unix/sysv/linux/gettimeofday.c        | 49 -------------
 .../unix/sysv/linux/powerpc/gettimeofday.c    | 69 +++++--------------
 sysdeps/unix/sysv/linux/x86/gettimeofday.c    | 43 +++++-------
 .../unix/sysv/linux/x86_64/x32/gettimeofday.c |  1 +
 .../unix/sysv/linux/x86_64/x32/syscalls.list  |  1 -
 time/gettimeofday.c                           | 32 ++++++---
 15 files changed, 121 insertions(+), 309 deletions(-)
 rename sysdeps/{unix => mach}/clock_gettime.c (65%)
 delete mode 100644 sysdeps/mach/gettimeofday.c
 delete mode 100644 sysdeps/posix/gettimeofday.c
 rename sysdeps/unix/sysv/linux/{i386 => alpha}/gettimeofday.c (58%)
 delete mode 100644 sysdeps/unix/sysv/linux/gettimeofday.c
 create mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c

-- 
2.17.1

Comments

Lukasz Majewski Oct. 28, 2019, 2:16 p.m. | #1
Hi Adhemerval,

> Use clock_gettime to implement gettimeofday

> 

> Changes from previous version:

> 

>   - Do not remove Linux arch-specific implementations.

> 

> --

> 

> Consolidate generic gettimeofday implementation to use clock_gettime.

> Linux ports that still provide gettimeofday through vDSO are not

> changed.

> 

> Remove sysdeps/unix/clock_gettime.c, which implemented clock_gettime

> using gettimeofday; new OS ports must provide a real implementation of

> clock_gettime.

> 

> Rename sysdeps/mach/gettimeofday.c to sysdeps/mach/clock_gettime.c and

> convert into an implementation of clock_gettime.  It only supports

> CLOCK_REALTIME; Mach does not appear to have any support for monotonic

> clocks.  It uses __host_get_time, which provides at best microsecond

> resolution.  Hurd is currently using sysdeps/posix/clock_getres.c for

> clock_getres; its output for CLOCK_REALTIME is based on

> sysconf (_SC_CLK_TCK), and I do not know whether that gives the

> correct result.

> 

> Unlike settimeofday, there are no known uses of gettimeofday's

> vestigial "get time zone" feature that are not bugs.  (The per-process

> timezone support in localtime and friends is unrelated, and the

> programs that set the kernel's offset between the hardware clock and

> UTC do not need to read it back.)  Therefore, this feature is dummied

> out.  Henceforth, if gettimeofday's "struct timezone" argument is not

> NULL, it will write zeroes to both fields.  Any program that is

> actually looking at this data will thus think it is running in UTC,

> which is probably more correct than whatever it was doing before.

> 

> [__]gettimeofday no longer has any internal callers, so we can now

> remove its internal prototype and PLT bypass aliases.  The

> __gettimeofday@GLIBC_2.0 export remains, in case it is used by any

> third-party code.

> 

> It also allows to simplify the arch-specific implementation on x86 and

> powerpc to remove the hack to disable the internal route to non iFUNC

> variant for internal symbol.

> 

> This patch also fixes a missing optimization on aarch64, powerpc, and

> x86 where the code used on static build do not use the vDSO.

> 

> Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc64le-linux-gnu,

> powerpc64-linux-gnu, powerpc-linux-gnu, and aarch64-linux-gnu.

> 

> Co-authored-by: Zack Weinberg <zackw@panix.com>

> ---

>  NEWS                                          | 15 ++++

>  include/sys/time.h                            |  2 -

>  sysdeps/{unix => mach}/clock_gettime.c        | 37 +++++-----

>  sysdeps/mach/gettimeofday.c                   | 43 ------------

>  sysdeps/posix/gettimeofday.c                  | 67 ------------------

>  sysdeps/unix/syscalls.list                    |  1 -

>  .../unix/sysv/linux/aarch64/gettimeofday.c    | 34 ++++-----

>  .../sysv/linux/{i386 => alpha}/gettimeofday.c | 25 ++-----

>  .../unix/sysv/linux/alpha/osf_gettimeofday.c  | 11 ++-

>  sysdeps/unix/sysv/linux/gettimeofday.c        | 49 -------------

>  .../unix/sysv/linux/powerpc/gettimeofday.c    | 69

> +++++-------------- sysdeps/unix/sysv/linux/x86/gettimeofday.c    |

> 43 +++++------- .../unix/sysv/linux/x86_64/x32/gettimeofday.c |  1 +

>  .../unix/sysv/linux/x86_64/x32/syscalls.list  |  1 -

>  time/gettimeofday.c                           | 32 ++++++---

>  15 files changed, 121 insertions(+), 309 deletions(-)

>  rename sysdeps/{unix => mach}/clock_gettime.c (65%)

>  delete mode 100644 sysdeps/mach/gettimeofday.c

>  delete mode 100644 sysdeps/posix/gettimeofday.c

>  rename sysdeps/unix/sysv/linux/{i386 => alpha}/gettimeofday.c (58%)

>  delete mode 100644 sysdeps/unix/sysv/linux/gettimeofday.c

>  create mode 100644 sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c

> 

> diff --git a/NEWS b/NEWS

> index 6d109f84f0..12d6af2fc0 100644

> --- a/NEWS

> +++ b/NEWS

> @@ -21,6 +21,21 @@ Major new features:

>    18661-1:2014 and TS 18661-3:2015 as amended by the resolution of

>    Clarification Request 13 to TS 18661-3.

>  

> +* The gettimeofday function will no longer report information about a

> +  system-wide time zone, expect for aarch64, powerpc, and x86 on

> Linux

> +  which still uses the vDSO symbol (when available).

> +

> +  This 4.2-BSD-era feature has been deprecated for many years, as it

> cannot

> +  handle the full complexity of the world’s timezones, but hitherto

> we have

> +  supported it on a best-effort basis.  Changes required to support

> 64-bit

> +  time_t on 32-bit architectures have made this no longer practical.

> +

> +  As of this release, callers of gettimeofday with a non-null ‘tzp’

> argument

> +  will always receive a ‘struct timezone’ whose tz_minuteswest and

> +  tz_dsttime fields are zero.  We have also arranged for call sites

> that

> +  pass a non-null ‘tzp’ argument to gettimeofday to receive

> compile-time

> +  warnings, if the compiler makes this possible.

> +

>  Deprecated and removed features, and other changes affecting

> compatibility: 

>  * The totalorder and totalordermag functions, and the corresponding

> diff --git a/include/sys/time.h b/include/sys/time.h

> index c0e30e70fb..2bf4297e76 100644

> --- a/include/sys/time.h

> +++ b/include/sys/time.h

> @@ -22,8 +22,6 @@

>  # ifndef _ISOMAC

>  extern int __gettimeofday (struct timeval *__tv,

>  			   struct timezone *__tz);

> -libc_hidden_proto (__gettimeofday)

> -libc_hidden_proto (gettimeofday)

>  extern int __settimezone (const struct timezone *__tz)

>  	attribute_hidden;

>  extern int __adjtime (const struct timeval *__delta,

> diff --git a/sysdeps/unix/clock_gettime.c

> b/sysdeps/mach/clock_gettime.c similarity index 65%

> rename from sysdeps/unix/clock_gettime.c

> rename to sysdeps/mach/clock_gettime.c

> index aa74e11703..0f872e5a45 100644

> --- a/sysdeps/unix/clock_gettime.c

> +++ b/sysdeps/mach/clock_gettime.c

> @@ -1,5 +1,4 @@

> -/* clock_gettime -- Get the current time from a POSIX clockid_t.

> Unix version.

> -   Copyright (C) 1999-2019 Free Software Foundation, Inc.

> +/* Copyright (C) 1991-2019 Free Software Foundation, Inc.

>     This file is part of the GNU C Library.

>  

>     The GNU C Library is free software; you can redistribute it and/or

> @@ -18,32 +17,28 @@

>  

>  #include <errno.h>

>  #include <time.h>

> -#include <sys/time.h>

> +#include <mach.h>

>  #include <shlib-compat.h>

>  

> -/* Get current value of CLOCK and store it in TP.  */

> +/* Get the current time of day, putting it into *TS.

> +   Returns 0 on success, -1 on errors.  */

>  int

> -__clock_gettime (clockid_t clock_id, struct timespec *tp)

> +__clock_gettime (clockid_t clock_id, struct timespec *ts)

>  {

> -  int retval = -1;

> -

> -  switch (clock_id)

> +  if (clock_id != CLOCK_REALTIME)

>      {

> -    case CLOCK_REALTIME:

> -      {

> -	struct timeval tv;

> -	retval = __gettimeofday (&tv, NULL);

> -	if (retval == 0)

> -	  TIMEVAL_TO_TIMESPEC (&tv, tp);

> -      }

> -      break;

> -

> -    default:

> -      __set_errno (EINVAL);

> -      break;

> +      errno = EINVAL;

> +      return -1;

>      }

>  

> -  return retval;

> +  /* __host_get_time can only fail if passed an invalid host_t.

> +     __mach_host_self could theoretically fail (producing an

> +     invalid host_t) due to resource exhaustion, but we assume

> +     this will never happen.  */

> +  time_value_t tv;

> +  __host_get_time (__mach_host_self (), &tv);

> +  TIME_VALUE_TO_TIMESPEC (&tv, ts);

> +  return 0;

>  }

>  libc_hidden_def (__clock_gettime)

>  

> diff --git a/sysdeps/mach/gettimeofday.c b/sysdeps/mach/gettimeofday.c

> deleted file mode 100644

> index f6df00306b..0000000000

> --- a/sysdeps/mach/gettimeofday.c

> +++ /dev/null

> @@ -1,43 +0,0 @@

> -/* Copyright (C) 1991-2019 Free Software Foundation, Inc.

> -   This file is part of the GNU C Library.

> -

> -   The GNU C Library is free software; you can redistribute it and/or

> -   modify it under the terms of the GNU Lesser General Public

> -   License as published by the Free Software Foundation; either

> -   version 2.1 of the License, or (at your option) any later version.

> -

> -   The GNU C Library is distributed in the hope that it will be

> useful,

> -   but WITHOUT ANY WARRANTY; without even the implied warranty of

> -   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

> -   Lesser General Public License for more details.

> -

> -   You should have received a copy of the GNU Lesser General Public

> -   License along with the GNU C Library; if not, see

> -   <https://www.gnu.org/licenses/>.  */

> -

> -#include <errno.h>

> -#include <stddef.h>

> -#include <sys/time.h>

> -#include <mach.h>

> -

> -/* Get the current time of day and timezone information,

> -   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.

> -   Returns 0 on success, -1 on errors.  */

> -int

> -__gettimeofday (struct timeval *tv, struct timezone *tz)

> -{

> -  kern_return_t err;

> -

> -  if (tz != NULL)

> -    *tz = (struct timezone){0, 0}; /* XXX */

> -

> -  if (err = __host_get_time (__mach_host_self (), (time_value_t *)

> tv))

> -    {

> -      errno = err;

> -      return -1;

> -    }

> -  return 0;

> -}

> -libc_hidden_def (__gettimeofday)

> -weak_alias (__gettimeofday, gettimeofday)

> -libc_hidden_weak (gettimeofday)

> diff --git a/sysdeps/posix/gettimeofday.c

> b/sysdeps/posix/gettimeofday.c deleted file mode 100644

> index 6bb98cd018..0000000000

> --- a/sysdeps/posix/gettimeofday.c

> +++ /dev/null

> @@ -1,67 +0,0 @@

> -/* Copyright (C) 1991-2019 Free Software Foundation, Inc.

> -   This file is part of the GNU C Library.

> -

> -   The GNU C Library is free software; you can redistribute it and/or

> -   modify it under the terms of the GNU Lesser General Public

> -   License as published by the Free Software Foundation; either

> -   version 2.1 of the License, or (at your option) any later version.

> -

> -   The GNU C Library is distributed in the hope that it will be

> useful,

> -   but WITHOUT ANY WARRANTY; without even the implied warranty of

> -   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

> -   Lesser General Public License for more details.

> -

> -   You should have received a copy of the GNU Lesser General Public

> -   License along with the GNU C Library; if not, see

> -   <https://www.gnu.org/licenses/>.  */

> -

> -#include <errno.h>

> -#include <time.h>

> -#include <sys/time.h>

> -

> -/* Get the current time of day and timezone information,

> -   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.

> -   Returns 0 on success, -1 on errors.  */

> -int

> -__gettimeofday (struct timeval *tv, struct timezone *tz)

> -{

> -  if (tv == NULL)

> -    {

> -      __set_errno (EINVAL);

> -      return -1;

> -    }

> -

> -  tv->tv_sec = (long int) time ((time_t *) NULL);

> -  tv->tv_usec = 0L;

> -

> -  if (tz != NULL)

> -    {

> -      const time_t timer = tv->tv_sec;

> -      struct tm tm;

> -      const struct tm *tmp;

> -

> -      const long int save_timezone = __timezone;

> -      const long int save_daylight = __daylight;

> -      char *save_tzname[2];

> -      save_tzname[0] = __tzname[0];

> -      save_tzname[1] = __tzname[1];

> -

> -      tmp = localtime_r (&timer, &tm);

> -

> -      tz->tz_minuteswest = __timezone / 60;

> -      tz->tz_dsttime = __daylight;

> -

> -      __timezone = save_timezone;

> -      __daylight = save_daylight;

> -      __tzname[0] = save_tzname[0];

> -      __tzname[1] = save_tzname[1];

> -

> -      if (tmp == NULL)

> -	return -1;

> -    }

> -

> -  return 0;

> -}

> -libc_hidden_def (__gettimeofday)

> -weak_alias (__gettimeofday, gettimeofday)

> -libc_hidden_weak (gettimeofday)

> diff --git a/sysdeps/unix/syscalls.list b/sysdeps/unix/syscalls.list

> index 5fedd5733d..e28e801c7a 100644

> --- a/sysdeps/unix/syscalls.list

> +++ b/sysdeps/unix/syscalls.list

> @@ -33,7 +33,6 @@ getrlimit	-	getrlimit

> i:ip	__getrlimit	getrlimit getrusage	-

> getrusage	i:ip	__getrusage	getrusage

> getsockname	-	getsockname	i:ibN

> __getsockname	getsockname getsockopt	-

> getsockopt	i:iiiBN	getsockopt -gettimeofday

> -	gettimeofday	i:pP	__gettimeofday

> gettimeofday getuid		-	getuid

> Ei:	__getuid	getuid ioctl		-

> ioctl		i:iiI	__ioctl		ioctl

> kill		-	kill		i:ii

> __kill		kill diff --git

> a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c

> b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c index

> 4ff74fa285..075af3d0d3 100644 ---

> a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c +++

> b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c @@ -20,39 +20,39 @@

> putting it into *tv and *tz.  If tz is null, *tz is not filled.

> Returns 0 on success, -1 on errors.  */ -#include <sys/time.h>

> +#include <time.h> +#include <sysdep.h> 

> -#ifdef SHARED

> -

> -# include <dl-vdso.h>

> -# include <sysdep-vdso.h>

> +#ifdef HAVE_GETTIMEOFDAY_VSYSCALL

> +# define HAVE_VSYSCALL

> +#endif

> +#include <sysdep-vdso.h>

>  

>  /* Used as a fallback in the ifunc resolver if VDSO is not available

>     and for libc.so internal __gettimeofday calls.  */

> -

>  static int

>  __gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz)

>  {

> +  if (__glibc_unlikely (tz != 0))

> +    memset (tz, 0, sizeof *tz);

> +

>    return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);

>  }

>  

> +#ifdef SHARED

> +# include <dl-vdso.h>

> +# include <sysdep-vdso.h>

> +

>  # define INIT_ARCH()

> -libc_ifunc_hidden (__gettimeofday, __gettimeofday,

> -		   (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)

> -		    ?: __gettimeofday_vsyscall))

> -libc_hidden_def (__gettimeofday)

> +libc_ifunc (__gettimeofday,

> +	    (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)

> +	    ?: __gettimeofday_vsyscall))

>  

>  #else

> -

> -# include <sysdep.h>

>  int

>  __gettimeofday (struct timeval *tv, struct timezone *tz)

>  {

> -  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);

> +  return __gettimeofday_vsyscall (tv, tz);

>  }

> -libc_hidden_def (__gettimeofday)

> -

>  #endif

> -

>  weak_alias (__gettimeofday, gettimeofday)

> -libc_hidden_weak (gettimeofday)

> diff --git a/sysdeps/unix/sysv/linux/i386/gettimeofday.c

> b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c similarity index 58%

> rename from sysdeps/unix/sysv/linux/i386/gettimeofday.c

> rename to sysdeps/unix/sysv/linux/alpha/gettimeofday.c

> index f6faecb21e..262a3c2352 100644

> --- a/sysdeps/unix/sysv/linux/i386/gettimeofday.c

> +++ b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c

> @@ -1,5 +1,5 @@

> -/* gettimeofday - get the time.  Linux/i386 version.

> -   Copyright (C) 2015-2019 Free Software Foundation, Inc.

> +/* gettimeofday -- Get the current time of day.  Linux/Alpha/tv64

> version.

> +   Copyright (C) 2019 Free Software Foundation, Inc.

>     This file is part of the GNU C Library.

>  

>     The GNU C Library is free software; you can redistribute it and/or

> @@ -16,20 +16,7 @@

>     License along with the GNU C Library; if not, see

>     <https://www.gnu.org/licenses/>.  */

>  

> -#ifdef SHARED

> -# define __gettimeofday __redirect___gettimeofday

> -#endif

> -

> -#include <sys/time.h>

> -

> -#ifdef SHARED

> -# undef __gettimeofday

> -# define __gettimeofday_type __redirect___gettimeofday

> -

> -# undef libc_hidden_def

> -# define libc_hidden_def(name) \

> -  __hidden_ver1 (__gettimeofday_syscall, __GI___gettimeofday, \

> -	       __gettimeofday_syscall);

> -#endif

> -

> -#include <sysdeps/unix/sysv/linux/x86/gettimeofday.c>

> +/* We can use the generic implementation, but we have to override its

> +   default symbol version.  */

> +#define VERSION_gettimeofday GLIBC_2.1

> +#include <time/gettimeofday.c>

> diff --git a/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c

> b/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c index

> e6cc522dd1..f602d8dcf9 100644 ---

> a/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c +++

> b/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c @@ -20,6 +20,8 @@

>  

>  #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)

>  

> +#include <string.h>

> +#include <time.h>

>  #include <sys/time.h>

>  #include <tv32-compat.h>

>  

> @@ -30,10 +32,13 @@ int

>  attribute_compat_text_section

>  __gettimeofday_tv32 (struct timeval32 *restrict tv32, void *restrict

> tz) {

> -  struct timeval tv;

> -  __gettimeofday (&tv, tz);

> +  if (__glibc_unlikely (tz != 0))

> +    memset (tz, 0, sizeof (struct timezone));

>  

> -  tv64_to_tv32 (tv32, &tv);

> +  struct timespec ts;

> +  __clock_gettime (CLOCK_REALTIME, &ts);

> +

> +  ts64_to_tv32 (tv32, &ts);


IMHO, this shall be replaced with valid_* functions from include/time.h

>    return 0;

>  }

>  

> diff --git a/sysdeps/unix/sysv/linux/gettimeofday.c

> b/sysdeps/unix/sysv/linux/gettimeofday.c deleted file mode 100644

> index c9597d6405..0000000000

> --- a/sysdeps/unix/sysv/linux/gettimeofday.c

> +++ /dev/null

> @@ -1,49 +0,0 @@

> -/* Copyright (C) 2015-2019 Free Software Foundation, Inc.

> -

> -   This file is part of the GNU C Library.

> -

> -   The GNU C Library is free software; you can redistribute it and/or

> -   modify it under the terms of the GNU Lesser General Public

> License as

> -   published by the Free Software Foundation; either version 2.1 of

> the

> -   License, or (at your option) any later version.

> -

> -   The GNU C Library is distributed in the hope that it will be

> useful,

> -   but WITHOUT ANY WARRANTY; without even the implied warranty of

> -   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

> -   Lesser General Public License for more details.

> -

> -   You should have received a copy of the GNU Lesser General Public

> -   License along with the GNU C Library; if not, see

> -   <https://www.gnu.org/licenses/>.  */

> -

> -#include <errno.h>

> -#include <sys/time.h>

> -

> -#undef __gettimeofday

> -

> -#ifdef HAVE_GETTIMEOFDAY_VSYSCALL

> -# define HAVE_VSYSCALL

> -#endif

> -#include <sysdep-vdso.h>

> -

> -/* Get the current time of day and timezone information,

> -   putting it into *tv and *tz.  If tz is null, *tz is not filled.

> -   Returns 0 on success, -1 on errors.  */

> -int

> -___gettimeofday (struct timeval *tv, struct timezone *tz)

> -{

> -  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);

> -}

> -

> -#ifdef VERSION_gettimeofday

> -weak_alias (___gettimeofday, __wgettimeofday);

> -default_symbol_version (___gettimeofday, __gettimeofday,

> VERSION_gettimeofday); -default_symbol_version (__wgettimeofday,

> gettimeofday, VERSION_gettimeofday); -libc_hidden_ver

> (___gettimeofday, __gettimeofday); -libc_hidden_ver (___gettimeofday,

> gettimeofday); -#else

> -strong_alias (___gettimeofday, __gettimeofday)

> -weak_alias (___gettimeofday, gettimeofday)

> -libc_hidden_def (__gettimeofday)

> -libc_hidden_weak (gettimeofday)

> -#endif

> diff --git a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c

> b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c index

> 13a1fd292a..02486dee3a 100644 ---

> a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c +++

> b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c @@ -15,71 +15,40 @@

>     License along with the GNU C Library; if not, see

>     <https://www.gnu.org/licenses/>.  */

>  

> -#if defined SHARED && !defined __powerpc64__

> -# define __gettimeofday __redirect___gettimeofday

> -#else

> -# define __redirect___gettimeofday __gettimeofday

> -#endif

> -

> -#include <sys/time.h>

> -

> -#ifdef SHARED

> -

> -# include <dl-vdso.h>

> -# include <libc-vdso.h>

> -# include <dl-machine.h>

> -# include <sysdep.h>

> -

> -# ifndef __powerpc64__

> -#  undef __gettimeofday

> -

> -int

> -__gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz)

> -{

> -  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);

> -}

> -

> -/* __GI___gettimeofday is defined as hidden and for ppc32 it enables

> the

> -   compiler make a local call (symbol@local) for internal GLIBC

> usage. It

> -   means the PLT won't be used and the ifunc resolver will be called

> directly.

> -   For ppc64 a call to a function in another translation unit might

> use a

> -   different toc pointer thus disallowing direct branchess and

> making internal

> -   ifuncs calls safe.  */

> -#  undef libc_hidden_def

> -#  define libc_hidden_def(name)

> 	\

> -  __hidden_ver1 (__gettimeofday_vsyscall,

> __GI___gettimeofday,	\

> -	       __gettimeofday_vsyscall);

> +#include <time.h>

> +#include <sysdep.h>

>  

> -# endif /* !__powerpc64__  */

> +#ifdef HAVE_GETTIMEOFDAY_VSYSCALL

> +# define HAVE_VSYSCALL

> +#endif

> +#include <sysdep-vdso.h>

>  

>  static int

>  __gettimeofday_syscall (struct timeval *tv, struct timezone *tz)

>  {

> -  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);

> +  if (__glibc_unlikely (tz != 0))

> +    memset (tz, 0, sizeof *tz);

> +

> +  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);

>  }

>  

> +#ifdef SHARED

> +# include <dl-vdso.h>

> +# include <libc-vdso.h>

> +

>  # define INIT_ARCH() \

>    void *vdso_gettimeofday = get_vdso_symbol

> (HAVE_GETTIMEOFDAY_VSYSCALL) 

>  /* If the vDSO is not available we fall back syscall.  */

> -libc_ifunc_hidden (__redirect___gettimeofday, __gettimeofday,

> -		   vdso_gettimeofday

> -		   ? VDSO_IFUNC_RET (vdso_gettimeofday)

> -		   : (void *) __gettimeofday_syscall);

> -libc_hidden_def (__gettimeofday)

> -

> +libc_ifunc (__gettimeofday,

> +	    vdso_gettimeofday

> +	    ? VDSO_IFUNC_RET (vdso_gettimeofday)

> +	    : (void *) __gettimeofday_syscall);

>  #else

> -

> -# include <sysdep.h>

> -# include <errno.h>

> -

>  int

>  __gettimeofday (struct timeval *tv, struct timezone *tz)

>  {

> -  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);

> +  return __gettimeofday_syscall (tv, tz);

>  }

> -libc_hidden_def (__gettimeofday)

> -

>  #endif

>  weak_alias (__gettimeofday, gettimeofday)

> -libc_hidden_weak (gettimeofday)

> diff --git a/sysdeps/unix/sysv/linux/x86/gettimeofday.c

> b/sysdeps/unix/sysv/linux/x86/gettimeofday.c index

> 2d9248ee26..cb20e358d8 100644 ---

> a/sysdeps/unix/sysv/linux/x86/gettimeofday.c +++

> b/sysdeps/unix/sysv/linux/x86/gettimeofday.c @@ -16,47 +16,38 @@

>     License along with the GNU C Library; if not, see

>     <https://www.gnu.org/licenses/>.  */

>  

> -#include <sys/time.h>

> +#include <time.h>

> +#include <sysdep.h>

>  

> -#ifdef SHARED

> -

> -# include <dl-vdso.h>

> -# include <errno.h>

> -# include <sysdep-vdso.h>

> -# include <sysdep-vdso.h>

> +#ifdef HAVE_GETTIMEOFDAY_VSYSCALL

> +# define HAVE_VSYSCALL

> +#endif

> +#include <sysdep-vdso.h>

>  

>  static int

>  __gettimeofday_syscall (struct timeval *tv, struct timezone *tz)

>  {

> -  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);

> +  if (__glibc_unlikely (tz != 0))

> +    memset (tz, 0, sizeof *tz);

> +

> +  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);

>  }

>  

> -# ifndef __gettimeofday_type

> -/* The i386 gettimeofday.c includes this file with a defined

> -   __gettimeofday_type macro.  For x86_64 we have to define it to

> __gettimeofday

> -   as the internal symbol is the ifunc'ed one.  */

> -#  define __gettimeofday_type __gettimeofday

> -# endif

> +#ifdef SHARED

> +# include <dl-vdso.h>

> +# include <libc-vdso.h>

>  

>  # define INIT_ARCH()

>  /* If the vDSO is not available we fall back to syscall.  */

> -libc_ifunc_hidden (__gettimeofday_type, __gettimeofday,

> -		   (get_vdso_symbol ("__vdso_gettimeofday")

> -		    ?: __gettimeofday_syscall));

> -libc_hidden_def (__gettimeofday)

> +libc_ifunc (__gettimeofday,

> +	    (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)

> +	    ?: __gettimeofday_syscall));

>  

>  #else

> -

> -# include <sysdep.h>

> -# include <errno.h>

> -

>  int

>  __gettimeofday (struct timeval *tv, struct timezone *tz)

>  {

> -  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);

> +  return __gettimeofday_syscall (tv, tz);

>  }

> -libc_hidden_def (__gettimeofday)

> -

>  #endif

>  weak_alias (__gettimeofday, gettimeofday)

> -libc_hidden_weak (gettimeofday)

> diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c

> b/sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c new file mode

> 100644 index 0000000000..cd342f33ad

> --- /dev/null

> +++ b/sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c

> @@ -0,0 +1 @@

> +#include <sysdeps/unix/sysv/linux/x86/gettimeofday.c>

> diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list

> b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list index

> b44f6f99e9..786c884232 100644 ---

> a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list +++

> b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list @@ -1,6 +1,5 @@

>  # File name	Caller	Syscall name	# args

> Strong name	Weak names 

> -gettimeofday	-

> gettimeofday:__vdso_gettimeofday@LINUX_2.6	i:pP

> __gettimeofday	gettimeofday personality	EXTRA

> personality	Ei:i	__personality	personality

> posix_fadvise64	-	fadvise64	Vi:iiii

> posix_fadvise	posix_fadvise64 time		-

> time:__vdso_time@LINUX_2.6			Ei:P	time

> diff --git a/time/gettimeofday.c b/time/gettimeofday.c index

> 1fd2669abd..e8055b397d 100644 --- a/time/gettimeofday.c +++

> b/time/gettimeofday.c @@ -15,20 +15,32 @@ License along with the GNU

> C Library; if not, see <https://www.gnu.org/licenses/>.  */

>  

> -#include <errno.h>

> +#include <string.h>

> +#include <time.h>

>  #include <sys/time.h>

>  

> -/* Get the current time of day and timezone information,

> -   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.

> +/* Get the current time of day, putting it into *TV.

> +   If *TZ is not NULL, clear it.

>     Returns 0 on success, -1 on errors.  */

>  int

> -__gettimeofday (struct timeval *tv, struct timezone *tz)

> +___gettimeofday (struct timeval *tv, struct timezone *tz)

>  {

> -  __set_errno (ENOSYS);

> -  return -1;

> +  if (__glibc_unlikely (tz != 0))

> +    memset (tz, 0, sizeof *tz);

> +

> +  struct timespec ts;

> +  if (__clock_gettime (CLOCK_REALTIME, &ts))

> +    return -1;

> +

> +  TIMESPEC_TO_TIMEVAL (tv, &ts);

> +  return 0;

>  }

> -libc_hidden_def (__gettimeofday)

> -weak_alias (__gettimeofday, gettimeofday)

> -libc_hidden_weak (gettimeofday)

>  

> -stub_warning (gettimeofday)

> +#ifdef VERSION_gettimeofday

> +weak_alias (___gettimeofday, __wgettimeofday);

> +default_symbol_version (___gettimeofday, __gettimeofday,

> VERSION_gettimeofday); +default_symbol_version (__wgettimeofday,

> gettimeofday, VERSION_gettimeofday); +#else

> +strong_alias (___gettimeofday, __gettimeofday)

> +weak_alias (___gettimeofday, gettimeofday)

> +#endif


Reviewed-by: Lukasz Majewski <lukma@denx.de>



Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de
Joseph Myers Oct. 28, 2019, 6:01 p.m. | #2
On Mon, 28 Oct 2019, Lukasz Majewski wrote:

> >  attribute_compat_text_section

> >  __gettimeofday_tv32 (struct timeval32 *restrict tv32, void *restrict

> > tz) {

> > -  struct timeval tv;

> > -  __gettimeofday (&tv, tz);

> > +  if (__glibc_unlikely (tz != 0))

> > +    memset (tz, 0, sizeof (struct timezone));

> >  

> > -  tv64_to_tv32 (tv32, &tv);

> > +  struct timespec ts;

> > +  __clock_gettime (CLOCK_REALTIME, &ts);

> > +

> > +  ts64_to_tv32 (tv32, &ts);

> 

> IMHO, this shall be replaced with valid_* functions from include/time.h


This is dealing with an alpha-specific timeval32 structure; I don't see 
how the functions in include/time.h are applicable.

-- 
Joseph S. Myers
joseph@codesourcery.com
Lukasz Majewski Oct. 29, 2019, 9:08 a.m. | #3
Hi Joseph,

> On Mon, 28 Oct 2019, Lukasz Majewski wrote:

> 

> > >  attribute_compat_text_section

> > >  __gettimeofday_tv32 (struct timeval32 *restrict tv32, void

> > > *restrict tz) {

> > > -  struct timeval tv;

> > > -  __gettimeofday (&tv, tz);

> > > +  if (__glibc_unlikely (tz != 0))

> > > +    memset (tz, 0, sizeof (struct timezone));

> > >  

> > > -  tv64_to_tv32 (tv32, &tv);

> > > +  struct timespec ts;

> > > +  __clock_gettime (CLOCK_REALTIME, &ts);

> > > +

> > > +  ts64_to_tv32 (tv32, &ts);  

> > 

> > IMHO, this shall be replaced with valid_* functions from

> > include/time.h  

> 

> This is dealing with an alpha-specific timeval32 structure; 


Maybe I did not noticed it earlier.

The tv32-compat.h defines [1]:
struct timeval32
{
  int32_t tv_sec;
  int32_t tv_usec;
};

and conversion functions - like ts64_to_tv32() are to handle this
specific type.

I do think that if struct timeval32 is alpha specific, then the
conversion functions shall be kept.

> I don't

> see how the functions in include/time.h are applicable.

> 


Ok.

Note:
[1] - https://patchwork.ozlabs.org/patch/1184084/


Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

Patch

diff --git a/NEWS b/NEWS
index 6d109f84f0..12d6af2fc0 100644
--- a/NEWS
+++ b/NEWS
@@ -21,6 +21,21 @@  Major new features:
   18661-1:2014 and TS 18661-3:2015 as amended by the resolution of
   Clarification Request 13 to TS 18661-3.
 
+* The gettimeofday function will no longer report information about a
+  system-wide time zone, expect for aarch64, powerpc, and x86 on Linux
+  which still uses the vDSO symbol (when available).
+
+  This 4.2-BSD-era feature has been deprecated for many years, as it cannot
+  handle the full complexity of the world’s timezones, but hitherto we have
+  supported it on a best-effort basis.  Changes required to support 64-bit
+  time_t on 32-bit architectures have made this no longer practical.
+
+  As of this release, callers of gettimeofday with a non-null ‘tzp’ argument
+  will always receive a ‘struct timezone’ whose tz_minuteswest and
+  tz_dsttime fields are zero.  We have also arranged for call sites that
+  pass a non-null ‘tzp’ argument to gettimeofday to receive compile-time
+  warnings, if the compiler makes this possible.
+
 Deprecated and removed features, and other changes affecting compatibility:
 
 * The totalorder and totalordermag functions, and the corresponding
diff --git a/include/sys/time.h b/include/sys/time.h
index c0e30e70fb..2bf4297e76 100644
--- a/include/sys/time.h
+++ b/include/sys/time.h
@@ -22,8 +22,6 @@ 
 # ifndef _ISOMAC
 extern int __gettimeofday (struct timeval *__tv,
 			   struct timezone *__tz);
-libc_hidden_proto (__gettimeofday)
-libc_hidden_proto (gettimeofday)
 extern int __settimezone (const struct timezone *__tz)
 	attribute_hidden;
 extern int __adjtime (const struct timeval *__delta,
diff --git a/sysdeps/unix/clock_gettime.c b/sysdeps/mach/clock_gettime.c
similarity index 65%
rename from sysdeps/unix/clock_gettime.c
rename to sysdeps/mach/clock_gettime.c
index aa74e11703..0f872e5a45 100644
--- a/sysdeps/unix/clock_gettime.c
+++ b/sysdeps/mach/clock_gettime.c
@@ -1,5 +1,4 @@ 
-/* clock_gettime -- Get the current time from a POSIX clockid_t.  Unix version.
-   Copyright (C) 1999-2019 Free Software Foundation, Inc.
+/* Copyright (C) 1991-2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -18,32 +17,28 @@ 
 
 #include <errno.h>
 #include <time.h>
-#include <sys/time.h>
+#include <mach.h>
 #include <shlib-compat.h>
 
-/* Get current value of CLOCK and store it in TP.  */
+/* Get the current time of day, putting it into *TS.
+   Returns 0 on success, -1 on errors.  */
 int
-__clock_gettime (clockid_t clock_id, struct timespec *tp)
+__clock_gettime (clockid_t clock_id, struct timespec *ts)
 {
-  int retval = -1;
-
-  switch (clock_id)
+  if (clock_id != CLOCK_REALTIME)
     {
-    case CLOCK_REALTIME:
-      {
-	struct timeval tv;
-	retval = __gettimeofday (&tv, NULL);
-	if (retval == 0)
-	  TIMEVAL_TO_TIMESPEC (&tv, tp);
-      }
-      break;
-
-    default:
-      __set_errno (EINVAL);
-      break;
+      errno = EINVAL;
+      return -1;
     }
 
-  return retval;
+  /* __host_get_time can only fail if passed an invalid host_t.
+     __mach_host_self could theoretically fail (producing an
+     invalid host_t) due to resource exhaustion, but we assume
+     this will never happen.  */
+  time_value_t tv;
+  __host_get_time (__mach_host_self (), &tv);
+  TIME_VALUE_TO_TIMESPEC (&tv, ts);
+  return 0;
 }
 libc_hidden_def (__clock_gettime)
 
diff --git a/sysdeps/mach/gettimeofday.c b/sysdeps/mach/gettimeofday.c
deleted file mode 100644
index f6df00306b..0000000000
--- a/sysdeps/mach/gettimeofday.c
+++ /dev/null
@@ -1,43 +0,0 @@ 
-/* Copyright (C) 1991-2019 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <errno.h>
-#include <stddef.h>
-#include <sys/time.h>
-#include <mach.h>
-
-/* Get the current time of day and timezone information,
-   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
-   Returns 0 on success, -1 on errors.  */
-int
-__gettimeofday (struct timeval *tv, struct timezone *tz)
-{
-  kern_return_t err;
-
-  if (tz != NULL)
-    *tz = (struct timezone){0, 0}; /* XXX */
-
-  if (err = __host_get_time (__mach_host_self (), (time_value_t *) tv))
-    {
-      errno = err;
-      return -1;
-    }
-  return 0;
-}
-libc_hidden_def (__gettimeofday)
-weak_alias (__gettimeofday, gettimeofday)
-libc_hidden_weak (gettimeofday)
diff --git a/sysdeps/posix/gettimeofday.c b/sysdeps/posix/gettimeofday.c
deleted file mode 100644
index 6bb98cd018..0000000000
--- a/sysdeps/posix/gettimeofday.c
+++ /dev/null
@@ -1,67 +0,0 @@ 
-/* Copyright (C) 1991-2019 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public
-   License as published by the Free Software Foundation; either
-   version 2.1 of the License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <errno.h>
-#include <time.h>
-#include <sys/time.h>
-
-/* Get the current time of day and timezone information,
-   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
-   Returns 0 on success, -1 on errors.  */
-int
-__gettimeofday (struct timeval *tv, struct timezone *tz)
-{
-  if (tv == NULL)
-    {
-      __set_errno (EINVAL);
-      return -1;
-    }
-
-  tv->tv_sec = (long int) time ((time_t *) NULL);
-  tv->tv_usec = 0L;
-
-  if (tz != NULL)
-    {
-      const time_t timer = tv->tv_sec;
-      struct tm tm;
-      const struct tm *tmp;
-
-      const long int save_timezone = __timezone;
-      const long int save_daylight = __daylight;
-      char *save_tzname[2];
-      save_tzname[0] = __tzname[0];
-      save_tzname[1] = __tzname[1];
-
-      tmp = localtime_r (&timer, &tm);
-
-      tz->tz_minuteswest = __timezone / 60;
-      tz->tz_dsttime = __daylight;
-
-      __timezone = save_timezone;
-      __daylight = save_daylight;
-      __tzname[0] = save_tzname[0];
-      __tzname[1] = save_tzname[1];
-
-      if (tmp == NULL)
-	return -1;
-    }
-
-  return 0;
-}
-libc_hidden_def (__gettimeofday)
-weak_alias (__gettimeofday, gettimeofday)
-libc_hidden_weak (gettimeofday)
diff --git a/sysdeps/unix/syscalls.list b/sysdeps/unix/syscalls.list
index 5fedd5733d..e28e801c7a 100644
--- a/sysdeps/unix/syscalls.list
+++ b/sysdeps/unix/syscalls.list
@@ -33,7 +33,6 @@  getrlimit	-	getrlimit	i:ip	__getrlimit	getrlimit
 getrusage	-	getrusage	i:ip	__getrusage	getrusage
 getsockname	-	getsockname	i:ibN	__getsockname	getsockname
 getsockopt	-	getsockopt	i:iiiBN	getsockopt
-gettimeofday	-	gettimeofday	i:pP	__gettimeofday	gettimeofday
 getuid		-	getuid		Ei:	__getuid	getuid
 ioctl		-	ioctl		i:iiI	__ioctl		ioctl
 kill		-	kill		i:ii	__kill		kill
diff --git a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c
index 4ff74fa285..075af3d0d3 100644
--- a/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/aarch64/gettimeofday.c
@@ -20,39 +20,39 @@ 
    putting it into *tv and *tz.  If tz is null, *tz is not filled.
    Returns 0 on success, -1 on errors.  */
 
-#include <sys/time.h>
+#include <time.h>
+#include <sysdep.h>
 
-#ifdef SHARED
-
-# include <dl-vdso.h>
-# include <sysdep-vdso.h>
+#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
+# define HAVE_VSYSCALL
+#endif
+#include <sysdep-vdso.h>
 
 /* Used as a fallback in the ifunc resolver if VDSO is not available
    and for libc.so internal __gettimeofday calls.  */
-
 static int
 __gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz)
 {
+  if (__glibc_unlikely (tz != 0))
+    memset (tz, 0, sizeof *tz);
+
   return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
 }
 
+#ifdef SHARED
+# include <dl-vdso.h>
+# include <sysdep-vdso.h>
+
 # define INIT_ARCH()
-libc_ifunc_hidden (__gettimeofday, __gettimeofday,
-		   (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)
-		    ?: __gettimeofday_vsyscall))
-libc_hidden_def (__gettimeofday)
+libc_ifunc (__gettimeofday,
+	    (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)
+	    ?: __gettimeofday_vsyscall))
 
 #else
-
-# include <sysdep.h>
 int
 __gettimeofday (struct timeval *tv, struct timezone *tz)
 {
-  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+  return __gettimeofday_vsyscall (tv, tz);
 }
-libc_hidden_def (__gettimeofday)
-
 #endif
-
 weak_alias (__gettimeofday, gettimeofday)
-libc_hidden_weak (gettimeofday)
diff --git a/sysdeps/unix/sysv/linux/i386/gettimeofday.c b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c
similarity index 58%
rename from sysdeps/unix/sysv/linux/i386/gettimeofday.c
rename to sysdeps/unix/sysv/linux/alpha/gettimeofday.c
index f6faecb21e..262a3c2352 100644
--- a/sysdeps/unix/sysv/linux/i386/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/alpha/gettimeofday.c
@@ -1,5 +1,5 @@ 
-/* gettimeofday - get the time.  Linux/i386 version.
-   Copyright (C) 2015-2019 Free Software Foundation, Inc.
+/* gettimeofday -- Get the current time of day.  Linux/Alpha/tv64 version.
+   Copyright (C) 2019 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -16,20 +16,7 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#ifdef SHARED
-# define __gettimeofday __redirect___gettimeofday
-#endif
-
-#include <sys/time.h>
-
-#ifdef SHARED
-# undef __gettimeofday
-# define __gettimeofday_type __redirect___gettimeofday
-
-# undef libc_hidden_def
-# define libc_hidden_def(name) \
-  __hidden_ver1 (__gettimeofday_syscall, __GI___gettimeofday, \
-	       __gettimeofday_syscall);
-#endif
-
-#include <sysdeps/unix/sysv/linux/x86/gettimeofday.c>
+/* We can use the generic implementation, but we have to override its
+   default symbol version.  */
+#define VERSION_gettimeofday GLIBC_2.1
+#include <time/gettimeofday.c>
diff --git a/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c b/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c
index e6cc522dd1..f602d8dcf9 100644
--- a/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/alpha/osf_gettimeofday.c
@@ -20,6 +20,8 @@ 
 
 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_1)
 
+#include <string.h>
+#include <time.h>
 #include <sys/time.h>
 #include <tv32-compat.h>
 
@@ -30,10 +32,13 @@  int
 attribute_compat_text_section
 __gettimeofday_tv32 (struct timeval32 *restrict tv32, void *restrict tz)
 {
-  struct timeval tv;
-  __gettimeofday (&tv, tz);
+  if (__glibc_unlikely (tz != 0))
+    memset (tz, 0, sizeof (struct timezone));
 
-  tv64_to_tv32 (tv32, &tv);
+  struct timespec ts;
+  __clock_gettime (CLOCK_REALTIME, &ts);
+
+  ts64_to_tv32 (tv32, &ts);
   return 0;
 }
 
diff --git a/sysdeps/unix/sysv/linux/gettimeofday.c b/sysdeps/unix/sysv/linux/gettimeofday.c
deleted file mode 100644
index c9597d6405..0000000000
--- a/sysdeps/unix/sysv/linux/gettimeofday.c
+++ /dev/null
@@ -1,49 +0,0 @@ 
-/* Copyright (C) 2015-2019 Free Software Foundation, Inc.
-
-   This file is part of the GNU C Library.
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Lesser General Public License as
-   published by the Free Software Foundation; either version 2.1 of the
-   License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Lesser General Public License for more details.
-
-   You should have received a copy of the GNU Lesser General Public
-   License along with the GNU C Library; if not, see
-   <https://www.gnu.org/licenses/>.  */
-
-#include <errno.h>
-#include <sys/time.h>
-
-#undef __gettimeofday
-
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-# define HAVE_VSYSCALL
-#endif
-#include <sysdep-vdso.h>
-
-/* Get the current time of day and timezone information,
-   putting it into *tv and *tz.  If tz is null, *tz is not filled.
-   Returns 0 on success, -1 on errors.  */
-int
-___gettimeofday (struct timeval *tv, struct timezone *tz)
-{
-  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
-}
-
-#ifdef VERSION_gettimeofday
-weak_alias (___gettimeofday, __wgettimeofday);
-default_symbol_version (___gettimeofday, __gettimeofday, VERSION_gettimeofday);
-default_symbol_version (__wgettimeofday,   gettimeofday, VERSION_gettimeofday);
-libc_hidden_ver (___gettimeofday, __gettimeofday);
-libc_hidden_ver (___gettimeofday, gettimeofday);
-#else
-strong_alias (___gettimeofday, __gettimeofday)
-weak_alias (___gettimeofday, gettimeofday)
-libc_hidden_def (__gettimeofday)
-libc_hidden_weak (gettimeofday)
-#endif
diff --git a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
index 13a1fd292a..02486dee3a 100644
--- a/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/powerpc/gettimeofday.c
@@ -15,71 +15,40 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#if defined SHARED && !defined __powerpc64__
-# define __gettimeofday __redirect___gettimeofday
-#else
-# define __redirect___gettimeofday __gettimeofday
-#endif
-
-#include <sys/time.h>
-
-#ifdef SHARED
-
-# include <dl-vdso.h>
-# include <libc-vdso.h>
-# include <dl-machine.h>
-# include <sysdep.h>
-
-# ifndef __powerpc64__
-#  undef __gettimeofday
-
-int
-__gettimeofday_vsyscall (struct timeval *tv, struct timezone *tz)
-{
-  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
-}
-
-/* __GI___gettimeofday is defined as hidden and for ppc32 it enables the
-   compiler make a local call (symbol@local) for internal GLIBC usage. It
-   means the PLT won't be used and the ifunc resolver will be called directly.
-   For ppc64 a call to a function in another translation unit might use a
-   different toc pointer thus disallowing direct branchess and making internal
-   ifuncs calls safe.  */
-#  undef libc_hidden_def
-#  define libc_hidden_def(name)					\
-  __hidden_ver1 (__gettimeofday_vsyscall, __GI___gettimeofday,	\
-	       __gettimeofday_vsyscall);
+#include <time.h>
+#include <sysdep.h>
 
-# endif /* !__powerpc64__  */
+#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
+# define HAVE_VSYSCALL
+#endif
+#include <sysdep-vdso.h>
 
 static int
 __gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
 {
-  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+  if (__glibc_unlikely (tz != 0))
+    memset (tz, 0, sizeof *tz);
+
+  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
 }
 
+#ifdef SHARED
+# include <dl-vdso.h>
+# include <libc-vdso.h>
+
 # define INIT_ARCH() \
   void *vdso_gettimeofday = get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)
 
 /* If the vDSO is not available we fall back syscall.  */
-libc_ifunc_hidden (__redirect___gettimeofday, __gettimeofday,
-		   vdso_gettimeofday
-		   ? VDSO_IFUNC_RET (vdso_gettimeofday)
-		   : (void *) __gettimeofday_syscall);
-libc_hidden_def (__gettimeofday)
-
+libc_ifunc (__gettimeofday,
+	    vdso_gettimeofday
+	    ? VDSO_IFUNC_RET (vdso_gettimeofday)
+	    : (void *) __gettimeofday_syscall);
 #else
-
-# include <sysdep.h>
-# include <errno.h>
-
 int
 __gettimeofday (struct timeval *tv, struct timezone *tz)
 {
-  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+  return __gettimeofday_syscall (tv, tz);
 }
-libc_hidden_def (__gettimeofday)
-
 #endif
 weak_alias (__gettimeofday, gettimeofday)
-libc_hidden_weak (gettimeofday)
diff --git a/sysdeps/unix/sysv/linux/x86/gettimeofday.c b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
index 2d9248ee26..cb20e358d8 100644
--- a/sysdeps/unix/sysv/linux/x86/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/x86/gettimeofday.c
@@ -16,47 +16,38 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <sys/time.h>
+#include <time.h>
+#include <sysdep.h>
 
-#ifdef SHARED
-
-# include <dl-vdso.h>
-# include <errno.h>
-# include <sysdep-vdso.h>
-# include <sysdep-vdso.h>
+#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
+# define HAVE_VSYSCALL
+#endif
+#include <sysdep-vdso.h>
 
 static int
 __gettimeofday_syscall (struct timeval *tv, struct timezone *tz)
 {
-  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+  if (__glibc_unlikely (tz != 0))
+    memset (tz, 0, sizeof *tz);
+
+  return INLINE_VSYSCALL (gettimeofday, 2, tv, tz);
 }
 
-# ifndef __gettimeofday_type
-/* The i386 gettimeofday.c includes this file with a defined
-   __gettimeofday_type macro.  For x86_64 we have to define it to __gettimeofday
-   as the internal symbol is the ifunc'ed one.  */
-#  define __gettimeofday_type __gettimeofday
-# endif
+#ifdef SHARED
+# include <dl-vdso.h>
+# include <libc-vdso.h>
 
 # define INIT_ARCH()
 /* If the vDSO is not available we fall back to syscall.  */
-libc_ifunc_hidden (__gettimeofday_type, __gettimeofday,
-		   (get_vdso_symbol ("__vdso_gettimeofday")
-		    ?: __gettimeofday_syscall));
-libc_hidden_def (__gettimeofday)
+libc_ifunc (__gettimeofday,
+	    (get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)
+	    ?: __gettimeofday_syscall));
 
 #else
-
-# include <sysdep.h>
-# include <errno.h>
-
 int
 __gettimeofday (struct timeval *tv, struct timezone *tz)
 {
-  return INLINE_SYSCALL (gettimeofday, 2, tv, tz);
+  return __gettimeofday_syscall (tv, tz);
 }
-libc_hidden_def (__gettimeofday)
-
 #endif
 weak_alias (__gettimeofday, gettimeofday)
-libc_hidden_weak (gettimeofday)
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c b/sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c
new file mode 100644
index 0000000000..cd342f33ad
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/gettimeofday.c
@@ -0,0 +1 @@ 
+#include <sysdeps/unix/sysv/linux/x86/gettimeofday.c>
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
index b44f6f99e9..786c884232 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/syscalls.list
@@ -1,6 +1,5 @@ 
 # File name	Caller	Syscall name	# args	Strong name	Weak names
 
-gettimeofday	-	gettimeofday:__vdso_gettimeofday@LINUX_2.6	i:pP	__gettimeofday	gettimeofday
 personality	EXTRA	personality	Ei:i	__personality	personality
 posix_fadvise64	-	fadvise64	Vi:iiii	posix_fadvise	posix_fadvise64
 time		-	time:__vdso_time@LINUX_2.6			Ei:P	time
diff --git a/time/gettimeofday.c b/time/gettimeofday.c
index 1fd2669abd..e8055b397d 100644
--- a/time/gettimeofday.c
+++ b/time/gettimeofday.c
@@ -15,20 +15,32 @@ 
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
+#include <string.h>
+#include <time.h>
 #include <sys/time.h>
 
-/* Get the current time of day and timezone information,
-   putting it into *TV and *TZ.  If TZ is NULL, *TZ is not filled.
+/* Get the current time of day, putting it into *TV.
+   If *TZ is not NULL, clear it.
    Returns 0 on success, -1 on errors.  */
 int
-__gettimeofday (struct timeval *tv, struct timezone *tz)
+___gettimeofday (struct timeval *tv, struct timezone *tz)
 {
-  __set_errno (ENOSYS);
-  return -1;
+  if (__glibc_unlikely (tz != 0))
+    memset (tz, 0, sizeof *tz);
+
+  struct timespec ts;
+  if (__clock_gettime (CLOCK_REALTIME, &ts))
+    return -1;
+
+  TIMESPEC_TO_TIMEVAL (tv, &ts);
+  return 0;
 }
-libc_hidden_def (__gettimeofday)
-weak_alias (__gettimeofday, gettimeofday)
-libc_hidden_weak (gettimeofday)
 
-stub_warning (gettimeofday)
+#ifdef VERSION_gettimeofday
+weak_alias (___gettimeofday, __wgettimeofday);
+default_symbol_version (___gettimeofday, __gettimeofday, VERSION_gettimeofday);
+default_symbol_version (__wgettimeofday,   gettimeofday, VERSION_gettimeofday);
+#else
+strong_alias (___gettimeofday, __gettimeofday)
+weak_alias (___gettimeofday, gettimeofday)
+#endif