diff mbox

[v3,09/16] elf: Move vDSO setup to rtld (BZ#24967)

Message ID 20191217214728.2886-9-adhemerval.zanella@linaro.org
State Dropped
Headers show

Commit Message

Adhemerval Zanella Dec. 17, 2019, 9:47 p.m. UTC
Changes from previous version:

  - Do not GLRO access on ifunc resolver, ut rather call the vDSO
    resolve function instead (dl_vdso_vsym).

--

This patch moves the vDSO setup from libc to loader code, just after
the vDSO link_map setup.  For static case the initialization
is moved to _dl_non_dynamic_init instead.

Instead of using the mangled pointer, the vDSO data is set as
attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for
static).  It is read-only even with partial relro.

It fixes BZ#24967 now that the vDSO pointer is setup earlier than
malloc interposition is called.

Also, vDSO calls should not be a problem for static dlopen as
indicated by BZ#20802.  The vDSO pointer would be zero-initialized
and the syscall will be issued instead.

Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu,
powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and
sparcv9-linux-gnu.  I also run some tests on mips.
---
 csu/init-first.c                              |  4 -
 elf/dl-support.c                              |  7 ++
 elf/rtld.c                                    |  7 +-
 malloc/tst-interpose-aux.c                    |  5 ++
 sysdeps/generic/dl-vdso-setup.c               |  1 +
 sysdeps/generic/dl-vdso-setup.h               | 28 ++++++
 sysdeps/generic/dl-vdso.h                     | 30 +++++++
 sysdeps/generic/ldsodefs.h                    |  6 ++
 sysdeps/powerpc/powerpc32/backtrace.c         | 16 ++--
 sysdeps/powerpc/powerpc64/backtrace.c         |  8 +-
 sysdeps/unix/sysv/linux/aarch64/Makefile      |  1 -
 sysdeps/unix/sysv/linux/arm/Makefile          |  1 -
 sysdeps/unix/sysv/linux/dl-vdso-setup.c       | 81 +++++++++++++++++
 sysdeps/unix/sysv/linux/dl-vdso-setup.h       | 55 ++++++++++++
 sysdeps/unix/sysv/linux/dl-vdso.c             | 48 ----------
 sysdeps/unix/sysv/linux/dl-vdso.h             | 30 ++++---
 sysdeps/unix/sysv/linux/gettimeofday.c        |  3 +-
 sysdeps/unix/sysv/linux/init-first.c          | 90 -------------------
 sysdeps/unix/sysv/linux/libc-vdso.h           | 30 +------
 sysdeps/unix/sysv/linux/mips/Makefile         |  2 -
 sysdeps/unix/sysv/linux/powerpc/Makefile      |  1 -
 .../sysv/linux/powerpc/get_timebase_freq.c    |  5 +-
 sysdeps/unix/sysv/linux/powerpc/init-first.c  | 50 -----------
 sysdeps/unix/sysv/linux/powerpc/libc-vdso.h   | 10 ---
 sysdeps/unix/sysv/linux/riscv/Makefile        |  4 -
 sysdeps/unix/sysv/linux/riscv/flush-icache.c  |  2 +-
 sysdeps/unix/sysv/linux/s390/Makefile         |  4 -
 sysdeps/unix/sysv/linux/sparc/Makefile        |  4 -
 sysdeps/unix/sysv/linux/sysdep-vdso.h         |  6 +-
 sysdeps/unix/sysv/linux/time.c                |  3 +-
 sysdeps/unix/sysv/linux/x86/Makefile          |  4 -
 31 files changed, 257 insertions(+), 289 deletions(-)
 create mode 100644 sysdeps/generic/dl-vdso-setup.c
 create mode 100644 sysdeps/generic/dl-vdso-setup.h
 create mode 100644 sysdeps/generic/dl-vdso.h
 create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.c
 create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.h
 delete mode 100644 sysdeps/unix/sysv/linux/dl-vdso.c
 delete mode 100644 sysdeps/unix/sysv/linux/init-first.c
 delete mode 100644 sysdeps/unix/sysv/linux/powerpc/init-first.c

Comments

Siddhesh Poyarekar Jan. 2, 2020, 12:55 p.m. UTC | #1
On 18/12/19 3:17 am, Adhemerval Zanella wrote:
> Changes from previous version:
> 
>   - Do not GLRO access on ifunc resolver, ut rather call the vDSO
>     resolve function instead (dl_vdso_vsym).
> 
> --
> 
> This patch moves the vDSO setup from libc to loader code, just after
> the vDSO link_map setup.  For static case the initialization
> is moved to _dl_non_dynamic_init instead.
> 
> Instead of using the mangled pointer, the vDSO data is set as
> attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for
> static).  It is read-only even with partial relro.
> 
> It fixes BZ#24967 now that the vDSO pointer is setup earlier than
> malloc interposition is called.
> 
> Also, vDSO calls should not be a problem for static dlopen as
> indicated by BZ#20802.  The vDSO pointer would be zero-initialized
> and the syscall will be issued instead.
> 
> Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
> arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu,
> powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and
> sparcv9-linux-gnu.  I also run some tests on mips.
> ---
>  csu/init-first.c                              |  4 -
>  elf/dl-support.c                              |  7 ++
>  elf/rtld.c                                    |  7 +-
>  malloc/tst-interpose-aux.c                    |  5 ++
>  sysdeps/generic/dl-vdso-setup.c               |  1 +
>  sysdeps/generic/dl-vdso-setup.h               | 28 ++++++
>  sysdeps/generic/dl-vdso.h                     | 30 +++++++
>  sysdeps/generic/ldsodefs.h                    |  6 ++
>  sysdeps/powerpc/powerpc32/backtrace.c         | 16 ++--
>  sysdeps/powerpc/powerpc64/backtrace.c         |  8 +-
>  sysdeps/unix/sysv/linux/aarch64/Makefile      |  1 -
>  sysdeps/unix/sysv/linux/arm/Makefile          |  1 -
>  sysdeps/unix/sysv/linux/dl-vdso-setup.c       | 81 +++++++++++++++++
>  sysdeps/unix/sysv/linux/dl-vdso-setup.h       | 55 ++++++++++++
>  sysdeps/unix/sysv/linux/dl-vdso.c             | 48 ----------
>  sysdeps/unix/sysv/linux/dl-vdso.h             | 30 ++++---
>  sysdeps/unix/sysv/linux/gettimeofday.c        |  3 +-
>  sysdeps/unix/sysv/linux/init-first.c          | 90 -------------------
>  sysdeps/unix/sysv/linux/libc-vdso.h           | 30 +------
>  sysdeps/unix/sysv/linux/mips/Makefile         |  2 -
>  sysdeps/unix/sysv/linux/powerpc/Makefile      |  1 -
>  .../sysv/linux/powerpc/get_timebase_freq.c    |  5 +-
>  sysdeps/unix/sysv/linux/powerpc/init-first.c  | 50 -----------
>  sysdeps/unix/sysv/linux/powerpc/libc-vdso.h   | 10 ---
>  sysdeps/unix/sysv/linux/riscv/Makefile        |  4 -
>  sysdeps/unix/sysv/linux/riscv/flush-icache.c  |  2 +-
>  sysdeps/unix/sysv/linux/s390/Makefile         |  4 -
>  sysdeps/unix/sysv/linux/sparc/Makefile        |  4 -
>  sysdeps/unix/sysv/linux/sysdep-vdso.h         |  6 +-
>  sysdeps/unix/sysv/linux/time.c                |  3 +-
>  sysdeps/unix/sysv/linux/x86/Makefile          |  4 -
>  31 files changed, 257 insertions(+), 289 deletions(-)
>  create mode 100644 sysdeps/generic/dl-vdso-setup.c
>  create mode 100644 sysdeps/generic/dl-vdso-setup.h
>  create mode 100644 sysdeps/generic/dl-vdso.h
>  create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.c
>  create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.h
>  delete mode 100644 sysdeps/unix/sysv/linux/dl-vdso.c
>  delete mode 100644 sysdeps/unix/sysv/linux/init-first.c
>  delete mode 100644 sysdeps/unix/sysv/linux/powerpc/init-first.c
> 

OK with some minor nits fixed, see below.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>


> diff --git a/csu/init-first.c b/csu/init-first.c
> index e0f489ee6d..891719a839 100644
> --- a/csu/init-first.c
> +++ b/csu/init-first.c
> @@ -74,10 +74,6 @@ _init (int argc, char **argv, char **envp)
>    _dl_non_dynamic_init ();
>  #endif
>  
> -#ifdef VDSO_SETUP
> -  VDSO_SETUP ();
> -#endif
> -
>    __init_misc (argc, argv, envp);
>  
>    /* Initialize ctype data.  */
> diff --git a/elf/dl-support.c b/elf/dl-support.c
> index b2b1b12f6f..81d44b0343 100644
> --- a/elf/dl-support.c
> +++ b/elf/dl-support.c
> @@ -34,6 +34,8 @@
>  #include <unsecvars.h>
>  #include <hp-timing.h>
>  #include <stackinfo.h>
> +#include <dl-vdso.h>
> +#include <dl-vdso-setup.h>
>  
>  extern char *__progname;
>  char **_dl_argv = &__progname;	/* This is checked for some error messages.  */
> @@ -201,6 +203,8 @@ struct link_map *_dl_sysinfo_map;
>  # include "get-dynamic-info.h"
>  #endif
>  #include "setup-vdso.h"
> +/* Define the vDSO function pointers.  */
> +#include <dl-vdso-setup.c>
>  
>  /* During the program run we must not modify the global data of
>     loaded shared object simultanously in two threads.  Therefore we
> @@ -315,6 +319,9 @@ _dl_non_dynamic_init (void)
>       so they can influence _dl_init_paths.  */
>    setup_vdso (NULL, NULL);
>  
> +  /* With vDSO setup we can initialize the function pointers.  */
> +  setup_vdso_pointers ();
> +
>    /* Initialize the data structures for the search paths for shared
>       objects.  */
>    _dl_init_paths (getenv ("LD_LIBRARY_PATH"));
> diff --git a/elf/rtld.c b/elf/rtld.c
> index dd8fc5e6c6..a06e13c657 100644
> --- a/elf/rtld.c
> +++ b/elf/rtld.c
> @@ -39,6 +39,8 @@
>  #include <dl-osinfo.h>
>  #include <dl-procinfo.h>
>  #include <dl-prop.h>
> +#include <dl-vdso.h>
> +#include <dl-vdso-setup.h>
>  #include <tls.h>
>  #include <stap-probe.h>
>  #include <stackinfo.h>
> @@ -833,7 +835,7 @@ security_init (void)
>    _dl_random = NULL;
>  }
>  
> -#include "setup-vdso.h"
> +#include <setup-vdso.h>
>  
>  /* The library search path.  */
>  static const char *library_path attribute_relro;
> @@ -1538,6 +1540,9 @@ ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
>       so they can influence _dl_init_paths.  */
>    setup_vdso (main_map, &first_preload);
>  
> +  /* With vDSO setup we can initialize the function pointers.  */
> +  setup_vdso_pointers ();
> +
>  #ifdef DL_SYSDEP_OSCHECK
>    DL_SYSDEP_OSCHECK (_dl_fatal_printf);
>  #endif
> diff --git a/malloc/tst-interpose-aux.c b/malloc/tst-interpose-aux.c
> index bbe321e843..8cbc3e6fea 100644
> --- a/malloc/tst-interpose-aux.c
> +++ b/malloc/tst-interpose-aux.c
> @@ -28,6 +28,7 @@
>  #include <sys/mman.h>
>  #include <sys/uio.h>
>  #include <unistd.h>
> +#include <time.h>
>  
>  #if INTERPOSE_THREADS
>  #include <pthread.h>
> @@ -96,6 +97,7 @@ struct __attribute__ ((aligned (__alignof__ (max_align_t)))) allocation_header
>  {
>    size_t allocation_index;
>    size_t allocation_size;
> +  struct timespec ts;
>  };
>  
>  /* Array of known allocations, to track invalid frees.  */
> @@ -166,6 +168,9 @@ malloc_internal (size_t size)
>        .allocation_index = index,
>        .allocation_size = allocation_size
>      };
> +  /* BZ#24967: Check if calling a symbol which may use the vDSO does not fail.
> +     The CLOCK_REALTIME should be supported on all systems.  */
> +  clock_gettime (CLOCK_REALTIME, &allocations[index]->ts);
>    return allocations[index] + 1;
>  }
>  
> diff --git a/sysdeps/generic/dl-vdso-setup.c b/sysdeps/generic/dl-vdso-setup.c
> new file mode 100644
> index 0000000000..6e25b021ab
> --- /dev/null
> +++ b/sysdeps/generic/dl-vdso-setup.c
> @@ -0,0 +1 @@
> +/* Empty.  */
> diff --git a/sysdeps/generic/dl-vdso-setup.h b/sysdeps/generic/dl-vdso-setup.h
> new file mode 100644
> index 0000000000..3d79bae317
> --- /dev/null
> +++ b/sysdeps/generic/dl-vdso-setup.h
> @@ -0,0 +1,28 @@
> +/* ELF symbol initialization functions for VDSO objects.
> +   Copyright (C) 2019 Free Software Foundation, Inc.

Update copyright year.

> +   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/>.  */
> +
> +#ifndef _DL_VDSO_INIT_H
> +#define _DL_VDSO_INIT_H
> +
> +/* Initialize the VDSO functions pointers.  */
> +static inline void __attribute__ ((always_inline))
> +setup_vdso_pointers (void)
> +{
> +}
> +
> +#endif
> diff --git a/sysdeps/generic/dl-vdso.h b/sysdeps/generic/dl-vdso.h
> new file mode 100644
> index 0000000000..5651f49a1a
> --- /dev/null
> +++ b/sysdeps/generic/dl-vdso.h
> @@ -0,0 +1,30 @@
> +/* ELF symbol resolve functions for VDSO objects.
> +   Copyright (C) 2019 Free Software Foundation, Inc.

Update copyright year.

> +   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/>.  */
> +
> +#ifndef _DL_VDSO_H
> +#define _DL_VDSO_H	1
> +
> +/* Function for resolving symbols in the VDSO link map.  Return the
> +   address of the vdso symbol NAME. */
> +static inline void *
> +dl_vdso_vsym (const char *name)
> +{
> +  return NULL;
> +}
> +
> +#endif
> diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
> index fc25a81e1c..8cbd0e87cc 100644
> --- a/sysdeps/generic/ldsodefs.h
> +++ b/sysdeps/generic/ldsodefs.h
> @@ -608,6 +608,12 @@ struct rtld_global_ro
>    /* At startup time we set up the normal DSO data structure for it,
>       and this points to it.  */
>    EXTERN struct link_map *_dl_sysinfo_map;
> +
> +# define PROCINFO_DECL
> +# ifndef PROCINFO_CLASS
> +#  define PROCINFO_CLASS EXTERN
> +# endif
> +# include <dl-vdso-setup.c>
>  #endif
>  
>    /* Mask for more hardware capabilities that are available on some
> diff --git a/sysdeps/powerpc/powerpc32/backtrace.c b/sysdeps/powerpc/powerpc32/backtrace.c
> index 2e6a859d9f..f2a57480a5 100644
> --- a/sysdeps/powerpc/powerpc32/backtrace.c
> +++ b/sysdeps/powerpc/powerpc32/backtrace.c
> @@ -51,14 +51,14 @@ struct signal_frame_32 {
>    /* We don't care about the rest, since IP value is at 'mctx' field.  */
>  };
>  
> -static inline int
> +static inline bool
>  is_sigtramp_address (void *nip)
>  {
>  #ifdef HAVE_SIGTRAMP_RT32
> -  if (nip == VDSO_SYMBOL (sigtramp32))
> -    return 1;
> +  if (nip == GLRO (dl_vdso_sigtramp_32))
> +    return true;
>  #endif
> -  return 0;
> +  return false;
>  }
>  
>  struct rt_signal_frame_32 {
> @@ -68,14 +68,14 @@ struct rt_signal_frame_32 {
>    /* We don't care about the rest, since IP value is at 'uc' field.  */
>  };
>  
> -static inline int
> +static inline bool
>  is_sigtramp_address_rt (void * nip)
>  {
>  #ifdef HAVE_SIGTRAMP_32
> -  if (nip == VDSO_SYMBOL (sigtramp_rt32))
> -    return 1;
> +  if (nip == GLRO (dl_vdso_sigtramp_rt32))
> +    return true;
>  #endif
> -  return 0;
> +  return false;
>  }
>  
>  int
> diff --git a/sysdeps/powerpc/powerpc64/backtrace.c b/sysdeps/powerpc/powerpc64/backtrace.c
> index 234d9c00dc..8ed5bc1585 100644
> --- a/sysdeps/powerpc/powerpc64/backtrace.c
> +++ b/sysdeps/powerpc/powerpc64/backtrace.c
> @@ -54,14 +54,14 @@ struct signal_frame_64 {
>    /* We don't care about the rest, since the IP value is at 'uc' field.  */
>  };
>  
> -static inline int
> +static inline bool
>  is_sigtramp_address (void *nip)
>  {
>  #ifdef HAVE_SIGTRAMP_RT64
> -  if (nip == VDSO_SYMBOL (sigtramp_rt64))
> -    return 1;
> +  if (nip == GLRO (dl_vdso_sigtramp_rt64))
> +    return true;
>  #endif
> -  return 0;
> +  return false;
>  }
>  
>  int
> diff --git a/sysdeps/unix/sysv/linux/aarch64/Makefile b/sysdeps/unix/sysv/linux/aarch64/Makefile
> index 57bbfeaac6..4bcae85bca 100644
> --- a/sysdeps/unix/sysv/linux/aarch64/Makefile
> +++ b/sysdeps/unix/sysv/linux/aarch64/Makefile
> @@ -5,7 +5,6 @@ shared-only-routines += libc-__read_tp
>  endif
>  
>  ifeq ($(subdir),elf)
> -sysdep_routines	     += dl-vdso
>  sysdep-rtld-routines += __read_tp
>  ifeq ($(build-shared),yes)
>  # This is needed for DSO loading from static binaries.
> diff --git a/sysdeps/unix/sysv/linux/arm/Makefile b/sysdeps/unix/sysv/linux/arm/Makefile
> index d7a2f6a8a7..abdf01f00c 100644
> --- a/sysdeps/unix/sysv/linux/arm/Makefile
> +++ b/sysdeps/unix/sysv/linux/arm/Makefile
> @@ -1,5 +1,4 @@
>  ifeq ($(subdir),elf)
> -sysdep_routines += dl-vdso
>  sysdep-rtld-routines += aeabi_read_tp libc-do-syscall
>  endif
>  
> diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.c b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
> new file mode 100644
> index 0000000000..1069879f1a
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
> @@ -0,0 +1,81 @@
> +/* Data for vDSO support.  Linux version.
> +   Copyright (C) 2019 Free Software Foundation, Inc.

Update copyright year.

> +   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/>.  */
> +
> +/* This file is included in three different modes for both static (libc.a)
> +   and shared (rtld) modes:
> +
> +   1. PROCINFO_DECL is defined, meaning we are only interested in
> +      declarations.  For static it requires use the extern keywork along with
> +      the attribute_relro while for shared it will be embedded in the
> +      rtld_global_ro.
> +
> +   2. PROCINFO_DECL and SHARED are not defined.  Nothing to do, the default
> +      zero initializion is suffice.
> +
> +   3. PROCINFO_DECL is not defined while SHARED is.  Similar to 2., the zero
> +      initialization of rtld_global_ro is suffice.  */
> +
> +#ifndef PROCINFO_CLASS
> +# define PROCINFO_CLASS
> +#endif
> +
> +#ifndef SHARED
> +# define RELRO attribute_relro
> +#else
> +# define RELRO
> +#endif
> +
> +#if defined PROCINFO_DECL || !defined SHARED
> +# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
> +PROCINFO_CLASS int (*_dl_vdso_clock_gettime) (clockid_t,
> +					      struct timespec *) RELRO;
> +#endif

Fix indentation.

> +# ifdef HAVE_GETTIMEOFDAY_VSYSCALL
> +PROCINFO_CLASS int (*_dl_vdso_gettimeofday) (struct timeval *, void *) RELRO;
> +#endif

Fix indentation.

> +# ifdef HAVE_TIME_VSYSCALL
> +PROCINFO_CLASS time_t (*_dl_vdso_time) (time_t *) RELRO;
> +# endif
> +# ifdef HAVE_GETCPU_VSYSCALL
> +PROCINFO_CLASS int (*_dl_vdso_getcpu) (unsigned *, unsigned *, void *) RELRO;
> +# endif
> +# ifdef HAVE_CLOCK_GETRES_VSYSCALL
> +PROCINFO_CLASS int (*_dl_vdso_clock_getres) (clockid_t,
> +					     struct timespec *) RELRO;
> +# endif
> +
> +/* PowerPC specific ones.  */
> +# ifdef HAVE_GET_TBFREQ
> +PROCINFO_CLASS uint64_t (*_dl_vdso_get_tbfreq)(void) RELRO;
> +# endif
> +/* The sigtramp are used on powerpc backtrace without using
> +   INLINE_VSYSCALL, so there is no need to set their type.  */
> +# ifdef HAVE_SIGTRAMP_RT64
> +PROCINFO_CLASS void *_dl_vdso_sigtramp_rt64 RELRO;
> +# endif
> +# ifdef HAVE_SIGTRAMP_RT32
> +PROCINFO_CLASS void *_dl_vdso_sigtramp_rt32 RELRO;
> +# endif
> +# ifdef HAVE_SIGTRAMP_32
> +PROCINFO_CLASS void *_dl_vdso_sigtramp_32 RELRO;
> +# endif
> +#endif
> +
> +#undef RELRO
> +#undef PROCINFO_DECL
> +#undef PROCINFO_CLASS
> diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.h b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
> new file mode 100644
> index 0000000000..f4e76202fc
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
> @@ -0,0 +1,55 @@
> +/* ELF symbol initialization functions for VDSO objects.  Linux version.
> +   Copyright (C) 2019 Free Software Foundation, Inc.

Update copyright year.

> +   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/>.  */
> +
> +#ifndef _DL_VDSO_INIT_H
> +#define _DL_VDSO_INIT_H
> +
> +/* Initialize the VDSO functions pointers.  */
> +static inline void __attribute__ ((always_inline))
> +setup_vdso_pointers (void)
> +{
> +#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
> +  GLRO(dl_vdso_clock_gettime) = dl_vdso_vsym (HAVE_CLOCK_GETTIME_VSYSCALL);
> +#endif
> +#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
> +  GLRO(dl_vdso_gettimeofday) = dl_vdso_vsym (HAVE_GETTIMEOFDAY_VSYSCALL);
> +#endif
> +#ifdef HAVE_TIME_VSYSCALL
> +  GLRO(dl_vdso_time) = dl_vdso_vsym (HAVE_TIME_VSYSCALL);
> +#endif
> +#ifdef HAVE_GETCPU_VSYSCALL
> +  GLRO(dl_vdso_getcpu) = dl_vdso_vsym (HAVE_GETCPU_VSYSCALL);
> +#endif
> +#ifdef HAVE_CLOCK_GETRES_VSYSCALL
> +  GLRO(dl_vdso_clock_getres) = dl_vdso_vsym (HAVE_CLOCK_GETRES_VSYSCALL);
> +#endif
> +#ifdef HAVE_GET_TBFREQ
> +  GLRO(dl_vdso_get_tbfreq) = dl_vdso_vsym (HAVE_GET_TBFREQ);
> +#endif
> +#ifdef HAVE_SIGTRAMP_RT64
> +  GLRO(dl_vdso_sigtramp_rt64) = dl_vdso_vsym (HAVE_SIGTRAMP_RT64);
> +#endif
> +#ifdef HAVE_SIGTRAMP_RT32
> +  GLRO(dl_vdso_sigtramp_rt32) = dl_vdso_vsym (HAVE_SIGTRAMP_RT32);
> +#endif
> +#ifdef HAVE_SIGTRAMP_32
> +  GLRO(dl_vdso_sigtramp_32) = dl_vdso_vsym (HAVE_SIGTRAMP_32);
> +#endif
> +}
> +
> +#endif
> diff --git a/sysdeps/unix/sysv/linux/dl-vdso.c b/sysdeps/unix/sysv/linux/dl-vdso.c
> deleted file mode 100644
> index 5577f2103c..0000000000
> --- a/sysdeps/unix/sysv/linux/dl-vdso.c
> +++ /dev/null
> @@ -1,48 +0,0 @@
> -/* ELF symbol resolve functions for VDSO objects.
> -   Copyright (C) 2005-2019 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 "config.h"
> -#include <ldsodefs.h>
> -
> -
> -void *
> -_dl_vdso_vsym (const char *name, const struct r_found_version *vers)
> -{
> -  struct link_map *map = GLRO (dl_sysinfo_map);
> -  void *value = NULL;
> -
> -
> -  if (map != NULL)
> -    {
> -      /* Use a WEAK REF so we don't error out if the symbol is not found.  */
> -      ElfW (Sym) wsym;
> -      memset (&wsym, 0, sizeof (ElfW (Sym)));
> -      wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
> -
> -      /* Search the scope of the vdso map.  */
> -      const ElfW (Sym) *ref = &wsym;
> -      lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref,
> -						   map->l_local_scope,
> -						   vers, 0, 0, NULL);
> -
> -      if (ref != NULL)
> -	value = DL_SYMBOL_ADDRESS (result, ref);
> -    }
> -
> -  return value;
> -}
> diff --git a/sysdeps/unix/sysv/linux/dl-vdso.h b/sysdeps/unix/sysv/linux/dl-vdso.h
> index 19ffd30c7e..d1e782b81f 100644
> --- a/sysdeps/unix/sysv/linux/dl-vdso.h
> +++ b/sysdeps/unix/sysv/linux/dl-vdso.h
> @@ -22,11 +22,6 @@
>  #include <ldsodefs.h>
>  #include <dl-hash.h>
>  
> -/* Functions for resolving symbols in the VDSO link map.  */
> -extern void *_dl_vdso_vsym (const char *name,
> -			    const struct r_found_version *version)
> -      attribute_hidden;
> -
>  /* If the architecture support vDSO it should define which is the expected
>     kernel version and hash value through both VDSO_NAME and VDSO_HASH
>     (usually defined at architecture sysdep.h).  */
> @@ -38,19 +33,26 @@ extern void *_dl_vdso_vsym (const char *name,
>  # define VDSO_HASH 0
>  #endif
>  
> +/* Functions for resolving symbols in the VDSO link map.  */
>  static inline void *
> -get_vdso_symbol (const char *symbol)
> +dl_vdso_vsym (const char *name)
>  {
> +  struct link_map *map = GLRO (dl_sysinfo_map);
> +  if (map == NULL)
> +    return NULL;
> +
> +  /* Use a WEAK REF so we don't error out if the symbol is not found.  */
> +  ElfW (Sym) wsym = { 0 };
> +  wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
> +
>    struct r_found_version rfv = { VDSO_NAME, VDSO_HASH, 1, NULL };
> -  return _dl_vdso_vsym (symbol, &rfv);
> -}
>  
> -static inline void *
> -get_vdso_mangle_symbol (const char *symbol)
> -{
> -  void *vdsop = get_vdso_symbol (symbol);
> -  PTR_MANGLE (vdsop);
> -  return vdsop;
> +  /* Search the scope of the vdso map.  */
> +  const ElfW (Sym) *ref = &wsym;
> +  lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref,
> +					       map->l_local_scope,
> +					       &rfv, 0, 0, NULL);
> +  return ref != NULL ? DL_SYMBOL_ADDRESS (result, ref) : NULL;
>  }
>  
>  #endif /* dl-vdso.h */
> diff --git a/sysdeps/unix/sysv/linux/gettimeofday.c b/sysdeps/unix/sysv/linux/gettimeofday.c
> index 600da6b468..6945be269c 100644
> --- a/sysdeps/unix/sysv/linux/gettimeofday.c
> +++ b/sysdeps/unix/sysv/linux/gettimeofday.c
> @@ -25,6 +25,7 @@
>  
>  # ifdef SHARED
>  #  include <dl-vdso.h>
> +# include <libc-vdso.h>
>  
>  static int
>  __gettimeofday_syscall (struct timeval *restrict tv, void *restrict tz)
> @@ -36,7 +37,7 @@ __gettimeofday_syscall (struct timeval *restrict tv, void *restrict tz)
>  
>  # undef INIT_ARCH
>  # define INIT_ARCH() \
> -  void *vdso_gettimeofday = get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)
> +  void *vdso_gettimeofday = dl_vdso_vsym (HAVE_GETTIMEOFDAY_VSYSCALL)
>  libc_ifunc (__gettimeofday,
>  	    vdso_gettimeofday ? VDSO_IFUNC_RET (vdso_gettimeofday)
>  			      : (void *) __gettimeofday_syscall)
> diff --git a/sysdeps/unix/sysv/linux/init-first.c b/sysdeps/unix/sysv/linux/init-first.c
> deleted file mode 100644
> index d005d13322..0000000000
> --- a/sysdeps/unix/sysv/linux/init-first.c
> +++ /dev/null
> @@ -1,90 +0,0 @@
> -/* vDSO internal symbols.  Linux generic 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
> -   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
> -   <http://www.gnu.org/licenses/>.  */
> -
> -#include <dl-vdso.h>
> -#include <libc-vdso.h>
> -
> -/* vDSO symbol used on clock_gettime implementation.  */
> -#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
> -int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
> -  attribute_hidden;
> -#endif
> -/* vDSO symbol used on clock_gettime64 implementation.  */
> -#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
> -int (*VDSO_SYMBOL(clock_gettime64)) (clockid_t, struct __timespec64 *)
> -  attribute_hidden;
> -#endif
> -/* vDSO symbol used on clock_getres implementation.  */
> -#ifdef HAVE_CLOCK_GETRES_VSYSCALL
> -int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
> -  attribute_hidden;
> -#endif
> -/* vDSO symbol used on gettimeofday implementation.  */
> -#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
> -int (*VDSO_SYMBOL (gettimeofday)) (struct timeval *, void *)
> -  attribute_hidden;
> -#endif
> -/* vDSO symbol used on GNU extension getcpu implementation.  */
> -#ifdef HAVE_GETCPU_VSYSCALL
> -long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
> -   attribute_hidden;
> -#endif
> -/* vDSO symbol used on time implementation.  */
> -#ifdef HAVE_TIME_VSYSCALL
> -time_t (*VDSO_SYMBOL(time)) (time_t *) attribute_hidden;
> -#endif
> -
> -static inline void
> -__libc_vdso_platform_setup (void)
> -{
> -#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
> -  VDSO_SYMBOL(clock_gettime)
> -    = get_vdso_mangle_symbol (HAVE_CLOCK_GETTIME_VSYSCALL);
> -#endif
> -
> -#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
> -  VDSO_SYMBOL(clock_gettime64)
> -    = get_vdso_mangle_symbol (HAVE_CLOCK_GETTIME64_VSYSCALL);
> -#endif
> -
> -#ifdef HAVE_CLOCK_GETRES_VSYSCALL
> -  VDSO_SYMBOL(clock_getres)
> -    = get_vdso_mangle_symbol (HAVE_CLOCK_GETRES_VSYSCALL);
> -#endif
> -
> -#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
> -  VDSO_SYMBOL(gettimeofday)
> -    = get_vdso_mangle_symbol (HAVE_GETTIMEOFDAY_VSYSCALL);
> -#endif
> -
> -#ifdef HAVE_GETCPU_VSYSCALL
> -  VDSO_SYMBOL(getcpu) = get_vdso_mangle_symbol (HAVE_GETCPU_VSYSCALL);
> -#endif
> -
> -#ifdef HAVE_TIME_VSYSCALL
> -  VDSO_SYMBOL(time) = get_vdso_mangle_symbol (HAVE_TIME_VSYSCALL);
> -#endif
> -
> -#ifdef VDSO_SETUP_ARCH
> -  VDSO_SETUP_ARCH ();
> -#endif
> -}
> -
> -#define VDSO_SETUP __libc_vdso_platform_setup
> -
> -#include <csu/init-first.c>
> diff --git a/sysdeps/unix/sysv/linux/libc-vdso.h b/sysdeps/unix/sysv/linux/libc-vdso.h
> index c6d505bab3..004faf0a97 100644
> --- a/sysdeps/unix/sysv/linux/libc-vdso.h
> +++ b/sysdeps/unix/sysv/linux/libc-vdso.h
> @@ -19,37 +19,9 @@
>  #ifndef _LIBC_VDSO_H
>  #define _LIBC_VDSO_H
>  
> -#define VDSO_SYMBOL(__name) __vdso_##__name
> -
>  /* Adjust the return IFUNC value from a vDSO symbol accordingly required
>     by the ELFv1 ABI.  It is used by the architecture to create an ODP
>     entry since the kernel vDSO does not provide it.  */
> -#ifndef VDSO_IFUNC_RET
> -# define VDSO_IFUNC_RET(__value) (__value)
> -#endif
> +#define VDSO_IFUNC_RET(__value) (__value)
>  
> -#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
> -extern int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
> -  attribute_hidden;
> -#endif
> -#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
> -extern int (*VDSO_SYMBOL(clock_gettime64)) (clockid_t, struct __timespec64 *)
> -  attribute_hidden;
> -#endif
> -#ifdef HAVE_CLOCK_GETRES_VSYSCALL
> -extern int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
> -  attribute_hidden;
>  #endif
> -#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
> -extern int (*VDSO_SYMBOL (gettimeofday)) (struct timeval *, void *)
> -  attribute_hidden;
> -#endif
> -#ifdef HAVE_GETCPU_VSYSCALL
> -extern long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
> -  attribute_hidden;
> -#endif
> -#ifdef HAVE_TIME_VSYSCALL
> -extern time_t (*VDSO_SYMBOL(time)) (time_t *) attribute_hidden;
> -#endif
> -
> -#endif /* _LIBC_VDSO_H */
> diff --git a/sysdeps/unix/sysv/linux/mips/Makefile b/sysdeps/unix/sysv/linux/mips/Makefile
> index 03044e7365..026ba242cf 100644
> --- a/sysdeps/unix/sysv/linux/mips/Makefile
> +++ b/sysdeps/unix/sysv/linux/mips/Makefile
> @@ -60,8 +60,6 @@ ifeq ($(subdir),elf)
>  ifeq ($(build-shared),yes)
>  # This is needed for DSO loading from static binaries.
>  sysdep-dl-routines += dl-static
> -
> -sysdep_routines += dl-vdso
>  endif
>  # If the compiler doesn't use GNU.stack note,
>  # this test is expected to fail.
> diff --git a/sysdeps/unix/sysv/linux/powerpc/Makefile b/sysdeps/unix/sysv/linux/powerpc/Makefile
> index 1596238afa..cc2f804d86 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/Makefile
> +++ b/sysdeps/unix/sysv/linux/powerpc/Makefile
> @@ -13,7 +13,6 @@ gen-as-const-headers += ucontext_i.sym
>  endif
>  
>  ifeq ($(subdir),elf)
> -sysdep_routines += dl-vdso
>  ifeq ($(build-shared),yes)
>  # This is needed for DSO loading from static binaries.
>  sysdep-dl-routines += dl-static
> diff --git a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
> index 29b6624b9a..11eb2b126d 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
> +++ b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
> @@ -21,7 +21,7 @@
>  
>  #include <libc-internal.h>
>  #include <not-cancel.h>
> -#include <libc-vdso.h>
> +#include <sysdep-vdso.h>
>  
>  static uint64_t
>  get_timebase_freq_fallback (void)
> @@ -101,8 +101,7 @@ uint64_t
>  __get_timebase_freq (void)
>  {
>    /* The vDSO does not have a fallback mechanism (such calling a syscall).  */
> -  __typeof (VDSO_SYMBOL (get_tbfreq)) vdsop = VDSO_SYMBOL (get_tbfreq);
> -  PTR_DEMANGLE (vdsop);
> +  uint64_t (*vdsop)(void) = GLRO(dl_vdso_get_tbfreq);
>    if (vdsop == NULL)
>      return get_timebase_freq_fallback ();
>  
> diff --git a/sysdeps/unix/sysv/linux/powerpc/init-first.c b/sysdeps/unix/sysv/linux/powerpc/init-first.c
> deleted file mode 100644
> index 92a4af83af..0000000000
> --- a/sysdeps/unix/sysv/linux/powerpc/init-first.c
> +++ /dev/null
> @@ -1,50 +0,0 @@
> -/* Initialization code run first thing by the ELF startup code.  Linux/PowerPC.
> -   Copyright (C) 2007-2019 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 <dl-vdso.h>
> -#include <libc-vdso.h>
> -
> -unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void) attribute_hidden;
> -#if defined(__PPC64__) || defined(__powerpc64__)
> -void *VDSO_SYMBOL(sigtramp_rt64) attribute_hidden;
> -#else
> -void *VDSO_SYMBOL(sigtramp32) attribute_hidden;
> -void *VDSO_SYMBOL(sigtramp_rt32) attribute_hidden;
> -#endif
> -
> -static inline void
> -__libc_vdso_platform_setup_arch (void)
> -{
> -  VDSO_SYMBOL (get_tbfreq) = get_vdso_mangle_symbol (HAVE_GET_TBFREQ);
> -
> -  /* PPC64 uses only one signal trampoline symbol, while PPC32 will use
> -     two depending if SA_SIGINFO is used (__kernel_sigtramp_rt32) or not
> -     (__kernel_sigtramp32).
> -     There is no need to pointer mangle these symbol because they will
> -     used only for pointer comparison.  */
> -#if defined(__PPC64__) || defined(__powerpc64__)
> -  VDSO_SYMBOL(sigtramp_rt64) =  get_vdso_symbol (HAVE_SIGTRAMP_RT64);
> -#else
> -  VDSO_SYMBOL(sigtramp32) = get_vdso_symbol (HAVE_SIGTRAMP_32);
> -  VDSO_SYMBOL(sigtramp_rt32) = get_vdso_symbol (HAVE_SIGTRAMP_RT32);
> -#endif
> -}
> -
> -#define VDSO_SETUP_ARCH __libc_vdso_platform_setup_arch
> -
> -#include <sysdeps/unix/sysv/linux/init-first.c>
> diff --git a/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
> index cb7da3b289..adc06d48b0 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
> +++ b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
> @@ -54,14 +54,4 @@
>  # define VDSO_IFUNC_RET(value)  ((void *) (value))
>  #endif
>  
> -#include_next <libc-vdso.h>
> -
> -extern unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void);
> -#if defined(__PPC64__) || defined(__powerpc64__)
> -extern void *VDSO_SYMBOL(sigtramp_rt64);
> -#else
> -extern void *VDSO_SYMBOL(sigtramp32);
> -extern void *VDSO_SYMBOL(sigtramp_rt32);
> -#endif
> -
>  #endif /* _LIBC_VDSO_H */
> diff --git a/sysdeps/unix/sysv/linux/riscv/Makefile b/sysdeps/unix/sysv/linux/riscv/Makefile
> index b7ad31885c..301b082398 100644
> --- a/sysdeps/unix/sysv/linux/riscv/Makefile
> +++ b/sysdeps/unix/sysv/linux/riscv/Makefile
> @@ -1,7 +1,3 @@
> -ifeq ($(subdir),elf)
> -sysdep_routines	+= dl-vdso
> -endif
> -
>  ifeq ($(subdir),misc)
>  sysdep_headers += sys/cachectl.h
>  sysdep_routines += flush-icache
> diff --git a/sysdeps/unix/sysv/linux/riscv/flush-icache.c b/sysdeps/unix/sysv/linux/riscv/flush-icache.c
> index c5bd60d9c2..e967e40deb 100644
> --- a/sysdeps/unix/sysv/linux/riscv/flush-icache.c
> +++ b/sysdeps/unix/sysv/linux/riscv/flush-icache.c
> @@ -38,7 +38,7 @@ __riscv_flush_icache_syscall (void *start, void *end, unsigned long int flags)
>  static func_type
>  __lookup_riscv_flush_icache (void)
>  {
> -  func_type func = get_vdso_symbol ("__vdso_flush_icache");
> +  func_type func = dl_vdso_vsym ("__vdso_flush_icache");
>  
>    /* If there is no vDSO entry then call the system call directly.  All Linux
>       versions provide the vDSO entry, but QEMU's user-mode emulation doesn't
> diff --git a/sysdeps/unix/sysv/linux/s390/Makefile b/sysdeps/unix/sysv/linux/s390/Makefile
> index 77f38523b5..d9db1b5422 100644
> --- a/sysdeps/unix/sysv/linux/s390/Makefile
> +++ b/sysdeps/unix/sysv/linux/s390/Makefile
> @@ -11,10 +11,6 @@ ifeq ($(subdir),stdlib)
>  gen-as-const-headers += ucontext_i.sym
>  endif
>  
> -ifeq ($(subdir),elf)
> -sysdep_routines += dl-vdso
> -endif
> -
>  ifeq ($(subdir),nptl)
>  libpthread-sysdep_routines += elision-lock elision-unlock elision-timed \
>  			      elision-trylock
> diff --git a/sysdeps/unix/sysv/linux/sparc/Makefile b/sysdeps/unix/sysv/linux/sparc/Makefile
> index fb3ee5b8a1..b0d182a439 100644
> --- a/sysdeps/unix/sysv/linux/sparc/Makefile
> +++ b/sysdeps/unix/sysv/linux/sparc/Makefile
> @@ -7,10 +7,6 @@ librt-routines += rt-sysdep
>  librt-shared-only-routines += rt-sysdep
>  endif
>  
> -ifeq ($(subdir),elf)
> -sysdep_routines += dl-vdso
> -endif
> -
>  ifeq ($(subdir),sysvipc)
>  sysdep_routines += getshmlba
>  endif
> diff --git a/sysdeps/unix/sysv/linux/sysdep-vdso.h b/sysdeps/unix/sysv/linux/sysdep-vdso.h
> index 76a211e39b..772313f97e 100644
> --- a/sysdeps/unix/sysv/linux/sysdep-vdso.h
> +++ b/sysdeps/unix/sysv/linux/sysdep-vdso.h
> @@ -19,8 +19,7 @@
>  #ifndef SYSDEP_VDSO_LINUX_H
>  # define SYSDEP_VDSO_LINUX_H
>  
> -#include <dl-vdso.h>
> -#include <libc-vdso.h>
> +#include <ldsodefs.h>
>  
>  #ifndef INTERNAL_VSYSCALL_CALL
>  # define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...)		      \
> @@ -34,8 +33,7 @@
>      INTERNAL_SYSCALL_DECL (sc_err);					      \
>      long int sc_ret;							      \
>  									      \
> -    __typeof (__vdso_##name) vdsop = __vdso_##name;			      \
> -    PTR_DEMANGLE (vdsop);						      \
> +    __typeof (GLRO(dl_vdso_##name)) vdsop = GLRO(dl_vdso_##name);	      \
>      if (vdsop != NULL)							      \
>        {									      \
>  	sc_ret = INTERNAL_VSYSCALL_CALL (vdsop, sc_err, nr, ##args);	      \
> diff --git a/sysdeps/unix/sysv/linux/time.c b/sysdeps/unix/sysv/linux/time.c
> index 0598958c9c..a7e4cbeb96 100644
> --- a/sysdeps/unix/sysv/linux/time.c
> +++ b/sysdeps/unix/sysv/linux/time.c
> @@ -25,6 +25,7 @@
>  
>  #ifdef SHARED
>  # include <dl-vdso.h>
> +# include <libc-vdso.h>
>  
>  static time_t
>  time_syscall (time_t *t)
> @@ -34,7 +35,7 @@ time_syscall (time_t *t)
>  
>  # undef INIT_ARCH
>  # define INIT_ARCH() \
> -  void *vdso_time = get_vdso_symbol (HAVE_TIME_VSYSCALL);
> +  void *vdso_time = dl_vdso_vsym (HAVE_TIME_VSYSCALL);
>  libc_ifunc (time,
>  	    vdso_time ? VDSO_IFUNC_RET (vdso_time)
>  		      : (void *) time_syscall);
> diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
> index 02ca36c6d2..b23b532590 100644
> --- a/sysdeps/unix/sysv/linux/x86/Makefile
> +++ b/sysdeps/unix/sysv/linux/x86/Makefile
> @@ -20,10 +20,6 @@ CFLAGS-elision-timed.c += -mrtm
>  CFLAGS-elision-trylock.c += -mrtm
>  endif
>  
> -ifeq ($(subdir),elf)
> -sysdep_routines += dl-vdso
> -endif
> -
>  ifeq ($(subdir),setjmp)
>  tests += tst-saved_mask-1
>  endif
>
Adhemerval Zanella Jan. 2, 2020, 1 p.m. UTC | #2
On 02/01/2020 09:55, Siddhesh Poyarekar wrote:
> On 18/12/19 3:17 am, Adhemerval Zanella wrote:
>> Changes from previous version:
>>
>>   - Do not GLRO access on ifunc resolver, ut rather call the vDSO
>>     resolve function instead (dl_vdso_vsym).
>>
>> --
>>
>> This patch moves the vDSO setup from libc to loader code, just after
>> the vDSO link_map setup.  For static case the initialization
>> is moved to _dl_non_dynamic_init instead.
>>
>> Instead of using the mangled pointer, the vDSO data is set as
>> attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for
>> static).  It is read-only even with partial relro.
>>
>> It fixes BZ#24967 now that the vDSO pointer is setup earlier than
>> malloc interposition is called.
>>
>> Also, vDSO calls should not be a problem for static dlopen as
>> indicated by BZ#20802.  The vDSO pointer would be zero-initialized
>> and the syscall will be issued instead.
>>
>> Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
>> arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu,
>> powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and
>> sparcv9-linux-gnu.  I also run some tests on mips.
>> ---
>>  csu/init-first.c                              |  4 -
>>  elf/dl-support.c                              |  7 ++
>>  elf/rtld.c                                    |  7 +-
>>  malloc/tst-interpose-aux.c                    |  5 ++
>>  sysdeps/generic/dl-vdso-setup.c               |  1 +
>>  sysdeps/generic/dl-vdso-setup.h               | 28 ++++++
>>  sysdeps/generic/dl-vdso.h                     | 30 +++++++
>>  sysdeps/generic/ldsodefs.h                    |  6 ++
>>  sysdeps/powerpc/powerpc32/backtrace.c         | 16 ++--
>>  sysdeps/powerpc/powerpc64/backtrace.c         |  8 +-
>>  sysdeps/unix/sysv/linux/aarch64/Makefile      |  1 -
>>  sysdeps/unix/sysv/linux/arm/Makefile          |  1 -
>>  sysdeps/unix/sysv/linux/dl-vdso-setup.c       | 81 +++++++++++++++++
>>  sysdeps/unix/sysv/linux/dl-vdso-setup.h       | 55 ++++++++++++
>>  sysdeps/unix/sysv/linux/dl-vdso.c             | 48 ----------
>>  sysdeps/unix/sysv/linux/dl-vdso.h             | 30 ++++---
>>  sysdeps/unix/sysv/linux/gettimeofday.c        |  3 +-
>>  sysdeps/unix/sysv/linux/init-first.c          | 90 -------------------
>>  sysdeps/unix/sysv/linux/libc-vdso.h           | 30 +------
>>  sysdeps/unix/sysv/linux/mips/Makefile         |  2 -
>>  sysdeps/unix/sysv/linux/powerpc/Makefile      |  1 -
>>  .../sysv/linux/powerpc/get_timebase_freq.c    |  5 +-
>>  sysdeps/unix/sysv/linux/powerpc/init-first.c  | 50 -----------
>>  sysdeps/unix/sysv/linux/powerpc/libc-vdso.h   | 10 ---
>>  sysdeps/unix/sysv/linux/riscv/Makefile        |  4 -
>>  sysdeps/unix/sysv/linux/riscv/flush-icache.c  |  2 +-
>>  sysdeps/unix/sysv/linux/s390/Makefile         |  4 -
>>  sysdeps/unix/sysv/linux/sparc/Makefile        |  4 -
>>  sysdeps/unix/sysv/linux/sysdep-vdso.h         |  6 +-
>>  sysdeps/unix/sysv/linux/time.c                |  3 +-
>>  sysdeps/unix/sysv/linux/x86/Makefile          |  4 -
>>  31 files changed, 257 insertions(+), 289 deletions(-)
>>  create mode 100644 sysdeps/generic/dl-vdso-setup.c
>>  create mode 100644 sysdeps/generic/dl-vdso-setup.h
>>  create mode 100644 sysdeps/generic/dl-vdso.h
>>  create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.c
>>  create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.h
>>  delete mode 100644 sysdeps/unix/sysv/linux/dl-vdso.c
>>  delete mode 100644 sysdeps/unix/sysv/linux/init-first.c
>>  delete mode 100644 sysdeps/unix/sysv/linux/powerpc/init-first.c
>>
> 
> OK with some minor nits fixed, see below.
> 
> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

>> diff --git a/sysdeps/generic/dl-vdso-setup.h b/sysdeps/generic/dl-vdso-setup.h
>> new file mode 100644
>> index 0000000000..3d79bae317
>> --- /dev/null
>> +++ b/sysdeps/generic/dl-vdso-setup.h
>> @@ -0,0 +1,28 @@
>> +/* ELF symbol initialization functions for VDSO objects.
>> +   Copyright (C) 2019 Free Software Foundation, Inc.
> 
> Update copyright year.

Ack.

> 
>> +   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/>.  */
>> +
>> +#ifndef _DL_VDSO_INIT_H
>> +#define _DL_VDSO_INIT_H
>> +
>> +/* Initialize the VDSO functions pointers.  */
>> +static inline void __attribute__ ((always_inline))
>> +setup_vdso_pointers (void)
>> +{
>> +}
>> +
>> +#endif
>> diff --git a/sysdeps/generic/dl-vdso.h b/sysdeps/generic/dl-vdso.h
>> new file mode 100644
>> index 0000000000..5651f49a1a
>> --- /dev/null
>> +++ b/sysdeps/generic/dl-vdso.h
>> @@ -0,0 +1,30 @@
>> +/* ELF symbol resolve functions for VDSO objects.
>> +   Copyright (C) 2019 Free Software Foundation, Inc.
> 
> Update copyright year.

Ack.

>> diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.c b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
>> new file mode 100644
>> index 0000000000..1069879f1a
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
>> @@ -0,0 +1,81 @@
>> +/* Data for vDSO support.  Linux version.
>> +   Copyright (C) 2019 Free Software Foundation, Inc.
> 
> Update copyright year.

Ack.

> 
>> +   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/>.  */
>> +
>> +/* This file is included in three different modes for both static (libc.a)
>> +   and shared (rtld) modes:
>> +
>> +   1. PROCINFO_DECL is defined, meaning we are only interested in
>> +      declarations.  For static it requires use the extern keywork along with
>> +      the attribute_relro while for shared it will be embedded in the
>> +      rtld_global_ro.
>> +
>> +   2. PROCINFO_DECL and SHARED are not defined.  Nothing to do, the default
>> +      zero initializion is suffice.
>> +
>> +   3. PROCINFO_DECL is not defined while SHARED is.  Similar to 2., the zero
>> +      initialization of rtld_global_ro is suffice.  */
>> +
>> +#ifndef PROCINFO_CLASS
>> +# define PROCINFO_CLASS
>> +#endif
>> +
>> +#ifndef SHARED
>> +# define RELRO attribute_relro
>> +#else
>> +# define RELRO
>> +#endif
>> +
>> +#if defined PROCINFO_DECL || !defined SHARED
>> +# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
>> +PROCINFO_CLASS int (*_dl_vdso_clock_gettime) (clockid_t,
>> +					      struct timespec *) RELRO;
>> +#endif
> 
> Fix indentation.

Ack.

> 
>> +# ifdef HAVE_GETTIMEOFDAY_VSYSCALL
>> +PROCINFO_CLASS int (*_dl_vdso_gettimeofday) (struct timeval *, void *) RELRO;
>> +#endif
> 
> Fix indentation.

Ack.
Lukasz Majewski Jan. 7, 2020, 4:13 p.m. UTC | #3
Hi Adhemerval, Siddhesh

> On 02/01/2020 09:55, Siddhesh Poyarekar wrote:
> > On 18/12/19 3:17 am, Adhemerval Zanella wrote:  
> >> Changes from previous version:
> >>
> >>   - Do not GLRO access on ifunc resolver, ut rather call the vDSO
> >>     resolve function instead (dl_vdso_vsym).
> >>
> >> --
> >>
> >> This patch moves the vDSO setup from libc to loader code, just
> >> after the vDSO link_map setup.  For static case the initialization
> >> is moved to _dl_non_dynamic_init instead.
> >>
> >> Instead of using the mangled pointer, the vDSO data is set as
> >> attribute_relro (on _rtld_global_ro for shared or _dl_vdso_* for
> >> static).  It is read-only even with partial relro.
> >>
> >> It fixes BZ#24967 now that the vDSO pointer is setup earlier than
> >> malloc interposition is called.
> >>
> >> Also, vDSO calls should not be a problem for static dlopen as
> >> indicated by BZ#20802.  The vDSO pointer would be zero-initialized
> >> and the syscall will be issued instead.
> >>
> >> Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
> >> arm-linux-gnueabihf, powerpc64le-linux-gnu, powerpc64-linux-gnu,
> >> powerpc-linux-gnu, s390x-linux-gnu, sparc64-linux-gnu, and
> >> sparcv9-linux-gnu.  I also run some tests on mips.
> >> ---
> >>  csu/init-first.c                              |  4 -
> >>  elf/dl-support.c                              |  7 ++
> >>  elf/rtld.c                                    |  7 +-
> >>  malloc/tst-interpose-aux.c                    |  5 ++
> >>  sysdeps/generic/dl-vdso-setup.c               |  1 +
> >>  sysdeps/generic/dl-vdso-setup.h               | 28 ++++++
> >>  sysdeps/generic/dl-vdso.h                     | 30 +++++++
> >>  sysdeps/generic/ldsodefs.h                    |  6 ++
> >>  sysdeps/powerpc/powerpc32/backtrace.c         | 16 ++--
> >>  sysdeps/powerpc/powerpc64/backtrace.c         |  8 +-
> >>  sysdeps/unix/sysv/linux/aarch64/Makefile      |  1 -
> >>  sysdeps/unix/sysv/linux/arm/Makefile          |  1 -
> >>  sysdeps/unix/sysv/linux/dl-vdso-setup.c       | 81
> >> +++++++++++++++++ sysdeps/unix/sysv/linux/dl-vdso-setup.h       |
> >> 55 ++++++++++++ sysdeps/unix/sysv/linux/dl-vdso.c             | 48
> >> ---------- sysdeps/unix/sysv/linux/dl-vdso.h             | 30
> >> ++++--- sysdeps/unix/sysv/linux/gettimeofday.c        |  3 +-
> >>  sysdeps/unix/sysv/linux/init-first.c          | 90
> >> ------------------- sysdeps/unix/sysv/linux/libc-vdso.h
> >> | 30 +------ sysdeps/unix/sysv/linux/mips/Makefile         |  2 -
> >>  sysdeps/unix/sysv/linux/powerpc/Makefile      |  1 -
> >>  .../sysv/linux/powerpc/get_timebase_freq.c    |  5 +-
> >>  sysdeps/unix/sysv/linux/powerpc/init-first.c  | 50 -----------
> >>  sysdeps/unix/sysv/linux/powerpc/libc-vdso.h   | 10 ---
> >>  sysdeps/unix/sysv/linux/riscv/Makefile        |  4 -
> >>  sysdeps/unix/sysv/linux/riscv/flush-icache.c  |  2 +-
> >>  sysdeps/unix/sysv/linux/s390/Makefile         |  4 -
> >>  sysdeps/unix/sysv/linux/sparc/Makefile        |  4 -
> >>  sysdeps/unix/sysv/linux/sysdep-vdso.h         |  6 +-
> >>  sysdeps/unix/sysv/linux/time.c                |  3 +-
> >>  sysdeps/unix/sysv/linux/x86/Makefile          |  4 -
> >>  31 files changed, 257 insertions(+), 289 deletions(-)
> >>  create mode 100644 sysdeps/generic/dl-vdso-setup.c
> >>  create mode 100644 sysdeps/generic/dl-vdso-setup.h
> >>  create mode 100644 sysdeps/generic/dl-vdso.h
> >>  create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.c
> >>  create mode 100644 sysdeps/unix/sysv/linux/dl-vdso-setup.h
> >>  delete mode 100644 sysdeps/unix/sysv/linux/dl-vdso.c
> >>  delete mode 100644 sysdeps/unix/sysv/linux/init-first.c
> >>  delete mode 100644 sysdeps/unix/sysv/linux/powerpc/init-first.c
> >>  
> > 
> > OK with some minor nits fixed, see below.
> > 
> > Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>  
> 
> >> diff --git a/sysdeps/generic/dl-vdso-setup.h
> >> b/sysdeps/generic/dl-vdso-setup.h new file mode 100644
> >> index 0000000000..3d79bae317
> >> --- /dev/null
> >> +++ b/sysdeps/generic/dl-vdso-setup.h
> >> @@ -0,0 +1,28 @@
> >> +/* ELF symbol initialization functions for VDSO objects.
> >> +   Copyright (C) 2019 Free Software Foundation, Inc.  
> > 
> > Update copyright year.  
> 
> Ack.
> 
> >   
> >> +   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/>.  */
> >> +
> >> +#ifndef _DL_VDSO_INIT_H
> >> +#define _DL_VDSO_INIT_H
> >> +
> >> +/* Initialize the VDSO functions pointers.  */
> >> +static inline void __attribute__ ((always_inline))
> >> +setup_vdso_pointers (void)
> >> +{
> >> +}
> >> +
> >> +#endif
> >> diff --git a/sysdeps/generic/dl-vdso.h b/sysdeps/generic/dl-vdso.h
> >> new file mode 100644
> >> index 0000000000..5651f49a1a
> >> --- /dev/null
> >> +++ b/sysdeps/generic/dl-vdso.h
> >> @@ -0,0 +1,30 @@
> >> +/* ELF symbol resolve functions for VDSO objects.
> >> +   Copyright (C) 2019 Free Software Foundation, Inc.  
> > 
> > Update copyright year.  
> 
> Ack.
> 
> >> diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.c
> >> b/sysdeps/unix/sysv/linux/dl-vdso-setup.c new file mode 100644
> >> index 0000000000..1069879f1a
> >> --- /dev/null
> >> +++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
> >> @@ -0,0 +1,81 @@
> >> +/* Data for vDSO support.  Linux version.
> >> +   Copyright (C) 2019 Free Software Foundation, Inc.  
> > 
> > Update copyright year.  
> 
> Ack.
> 
> >   
> >> +   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/>.  */
> >> +
> >> +/* This file is included in three different modes for both static
> >> (libc.a)
> >> +   and shared (rtld) modes:
> >> +
> >> +   1. PROCINFO_DECL is defined, meaning we are only interested in
> >> +      declarations.  For static it requires use the extern
> >> keywork along with
> >> +      the attribute_relro while for shared it will be embedded in
> >> the
> >> +      rtld_global_ro.
> >> +
> >> +   2. PROCINFO_DECL and SHARED are not defined.  Nothing to do,
> >> the default
> >> +      zero initializion is suffice.
> >> +
> >> +   3. PROCINFO_DECL is not defined while SHARED is.  Similar to
> >> 2., the zero
> >> +      initialization of rtld_global_ro is suffice.  */
> >> +
> >> +#ifndef PROCINFO_CLASS
> >> +# define PROCINFO_CLASS
> >> +#endif
> >> +
> >> +#ifndef SHARED
> >> +# define RELRO attribute_relro
> >> +#else
> >> +# define RELRO
> >> +#endif
> >> +
> >> +#if defined PROCINFO_DECL || !defined SHARED
> >> +# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
> >> +PROCINFO_CLASS int (*_dl_vdso_clock_gettime) (clockid_t,
> >> +					      struct timespec *)
> >> RELRO; +#endif  
> > 
> > Fix indentation.  
> 
> Ack.
> 
> >   
> >> +# ifdef HAVE_GETTIMEOFDAY_VSYSCALL
> >> +PROCINFO_CLASS int (*_dl_vdso_gettimeofday) (struct timeval *,
> >> void *) RELRO; +#endif  
> > 
> > Fix indentation.  
> 
> Ack.

Unfortunately this patch caused regression on my ARMv7 32 bit setup.
Please find filled in bugzilla entry:

https://sourceware.org/bugzilla/show_bug.cgi?id=25352


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
Adhemerval Zanella Jan. 7, 2020, 7:40 p.m. UTC | #4
On 07/01/2020 13:13, Lukasz Majewski wrote:
> 
> Unfortunately this patch caused regression on my ARMv7 32 bit setup.
> Please find filled in bugzilla entry:
> 
> https://sourceware.org/bugzilla/show_bug.cgi?id=25352

Are you sure you are testing it properly? As indicated by Andreas, it
seems a mismatch between ld.so and libc.so.  I just setup a debian 9 
VM with both a 4.9 and 5.4 kernel and a simple test:

--
#include <time.h>

int main ()
{
  clock_gettime (CLOCK_REALTIME, &(struct timespec) {});
  clock_gettime (CLOCK_MONOTONIC, &(struct timespec) {});
  clock_gettime (CLOCK_BOOTTIME, &(struct timespec) {});

  return 0;
}
--

does show the expected results.  On 4.9 kernel I am seeing:

15:36:06 syscall_0x193(0, 0xbed9a3d8, 0xc8, 0, 0xbed9a3d8, 0) = -1 ENOSYS (Function not implemented)
15:36:06 clock_gettime(CLOCK_BOOTTIME, {tv_sec=1303, tv_nsec=570795799}) = 0
15:36:06 exit_group(0)                  = ?
15:36:06 +++ exited with 0 +++

While on a 5.4 kernel:

syscall_0x193(0, 0xbedfb3e8, 0xc8, 0, 0xbedfb3e8, 0) = 0
syscall_0x193(0x1, 0xbedfb3e8, 0xc8, 0, 0xbedfb3e8, 0x1) = 0
syscall_0x193(0x7, 0xbedfb3e8, 0xc8, 0, 0xbedfb3e8, 0x7) = 0

(arm clock_gettime64 vDSO was added on 5.5).
diff mbox

Patch

diff --git a/csu/init-first.c b/csu/init-first.c
index e0f489ee6d..891719a839 100644
--- a/csu/init-first.c
+++ b/csu/init-first.c
@@ -74,10 +74,6 @@  _init (int argc, char **argv, char **envp)
   _dl_non_dynamic_init ();
 #endif
 
-#ifdef VDSO_SETUP
-  VDSO_SETUP ();
-#endif
-
   __init_misc (argc, argv, envp);
 
   /* Initialize ctype data.  */
diff --git a/elf/dl-support.c b/elf/dl-support.c
index b2b1b12f6f..81d44b0343 100644
--- a/elf/dl-support.c
+++ b/elf/dl-support.c
@@ -34,6 +34,8 @@ 
 #include <unsecvars.h>
 #include <hp-timing.h>
 #include <stackinfo.h>
+#include <dl-vdso.h>
+#include <dl-vdso-setup.h>
 
 extern char *__progname;
 char **_dl_argv = &__progname;	/* This is checked for some error messages.  */
@@ -201,6 +203,8 @@  struct link_map *_dl_sysinfo_map;
 # include "get-dynamic-info.h"
 #endif
 #include "setup-vdso.h"
+/* Define the vDSO function pointers.  */
+#include <dl-vdso-setup.c>
 
 /* During the program run we must not modify the global data of
    loaded shared object simultanously in two threads.  Therefore we
@@ -315,6 +319,9 @@  _dl_non_dynamic_init (void)
      so they can influence _dl_init_paths.  */
   setup_vdso (NULL, NULL);
 
+  /* With vDSO setup we can initialize the function pointers.  */
+  setup_vdso_pointers ();
+
   /* Initialize the data structures for the search paths for shared
      objects.  */
   _dl_init_paths (getenv ("LD_LIBRARY_PATH"));
diff --git a/elf/rtld.c b/elf/rtld.c
index dd8fc5e6c6..a06e13c657 100644
--- a/elf/rtld.c
+++ b/elf/rtld.c
@@ -39,6 +39,8 @@ 
 #include <dl-osinfo.h>
 #include <dl-procinfo.h>
 #include <dl-prop.h>
+#include <dl-vdso.h>
+#include <dl-vdso-setup.h>
 #include <tls.h>
 #include <stap-probe.h>
 #include <stackinfo.h>
@@ -833,7 +835,7 @@  security_init (void)
   _dl_random = NULL;
 }
 
-#include "setup-vdso.h"
+#include <setup-vdso.h>
 
 /* The library search path.  */
 static const char *library_path attribute_relro;
@@ -1538,6 +1540,9 @@  ERROR: '%s': cannot process note segment.\n", _dl_argv[0]);
      so they can influence _dl_init_paths.  */
   setup_vdso (main_map, &first_preload);
 
+  /* With vDSO setup we can initialize the function pointers.  */
+  setup_vdso_pointers ();
+
 #ifdef DL_SYSDEP_OSCHECK
   DL_SYSDEP_OSCHECK (_dl_fatal_printf);
 #endif
diff --git a/malloc/tst-interpose-aux.c b/malloc/tst-interpose-aux.c
index bbe321e843..8cbc3e6fea 100644
--- a/malloc/tst-interpose-aux.c
+++ b/malloc/tst-interpose-aux.c
@@ -28,6 +28,7 @@ 
 #include <sys/mman.h>
 #include <sys/uio.h>
 #include <unistd.h>
+#include <time.h>
 
 #if INTERPOSE_THREADS
 #include <pthread.h>
@@ -96,6 +97,7 @@  struct __attribute__ ((aligned (__alignof__ (max_align_t)))) allocation_header
 {
   size_t allocation_index;
   size_t allocation_size;
+  struct timespec ts;
 };
 
 /* Array of known allocations, to track invalid frees.  */
@@ -166,6 +168,9 @@  malloc_internal (size_t size)
       .allocation_index = index,
       .allocation_size = allocation_size
     };
+  /* BZ#24967: Check if calling a symbol which may use the vDSO does not fail.
+     The CLOCK_REALTIME should be supported on all systems.  */
+  clock_gettime (CLOCK_REALTIME, &allocations[index]->ts);
   return allocations[index] + 1;
 }
 
diff --git a/sysdeps/generic/dl-vdso-setup.c b/sysdeps/generic/dl-vdso-setup.c
new file mode 100644
index 0000000000..6e25b021ab
--- /dev/null
+++ b/sysdeps/generic/dl-vdso-setup.c
@@ -0,0 +1 @@ 
+/* Empty.  */
diff --git a/sysdeps/generic/dl-vdso-setup.h b/sysdeps/generic/dl-vdso-setup.h
new file mode 100644
index 0000000000..3d79bae317
--- /dev/null
+++ b/sysdeps/generic/dl-vdso-setup.h
@@ -0,0 +1,28 @@ 
+/* ELF symbol initialization functions for VDSO objects.
+   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
+   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/>.  */
+
+#ifndef _DL_VDSO_INIT_H
+#define _DL_VDSO_INIT_H
+
+/* Initialize the VDSO functions pointers.  */
+static inline void __attribute__ ((always_inline))
+setup_vdso_pointers (void)
+{
+}
+
+#endif
diff --git a/sysdeps/generic/dl-vdso.h b/sysdeps/generic/dl-vdso.h
new file mode 100644
index 0000000000..5651f49a1a
--- /dev/null
+++ b/sysdeps/generic/dl-vdso.h
@@ -0,0 +1,30 @@ 
+/* ELF symbol resolve functions for VDSO objects.
+   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
+   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/>.  */
+
+#ifndef _DL_VDSO_H
+#define _DL_VDSO_H	1
+
+/* Function for resolving symbols in the VDSO link map.  Return the
+   address of the vdso symbol NAME. */
+static inline void *
+dl_vdso_vsym (const char *name)
+{
+  return NULL;
+}
+
+#endif
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index fc25a81e1c..8cbd0e87cc 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -608,6 +608,12 @@  struct rtld_global_ro
   /* At startup time we set up the normal DSO data structure for it,
      and this points to it.  */
   EXTERN struct link_map *_dl_sysinfo_map;
+
+# define PROCINFO_DECL
+# ifndef PROCINFO_CLASS
+#  define PROCINFO_CLASS EXTERN
+# endif
+# include <dl-vdso-setup.c>
 #endif
 
   /* Mask for more hardware capabilities that are available on some
diff --git a/sysdeps/powerpc/powerpc32/backtrace.c b/sysdeps/powerpc/powerpc32/backtrace.c
index 2e6a859d9f..f2a57480a5 100644
--- a/sysdeps/powerpc/powerpc32/backtrace.c
+++ b/sysdeps/powerpc/powerpc32/backtrace.c
@@ -51,14 +51,14 @@  struct signal_frame_32 {
   /* We don't care about the rest, since IP value is at 'mctx' field.  */
 };
 
-static inline int
+static inline bool
 is_sigtramp_address (void *nip)
 {
 #ifdef HAVE_SIGTRAMP_RT32
-  if (nip == VDSO_SYMBOL (sigtramp32))
-    return 1;
+  if (nip == GLRO (dl_vdso_sigtramp_32))
+    return true;
 #endif
-  return 0;
+  return false;
 }
 
 struct rt_signal_frame_32 {
@@ -68,14 +68,14 @@  struct rt_signal_frame_32 {
   /* We don't care about the rest, since IP value is at 'uc' field.  */
 };
 
-static inline int
+static inline bool
 is_sigtramp_address_rt (void * nip)
 {
 #ifdef HAVE_SIGTRAMP_32
-  if (nip == VDSO_SYMBOL (sigtramp_rt32))
-    return 1;
+  if (nip == GLRO (dl_vdso_sigtramp_rt32))
+    return true;
 #endif
-  return 0;
+  return false;
 }
 
 int
diff --git a/sysdeps/powerpc/powerpc64/backtrace.c b/sysdeps/powerpc/powerpc64/backtrace.c
index 234d9c00dc..8ed5bc1585 100644
--- a/sysdeps/powerpc/powerpc64/backtrace.c
+++ b/sysdeps/powerpc/powerpc64/backtrace.c
@@ -54,14 +54,14 @@  struct signal_frame_64 {
   /* We don't care about the rest, since the IP value is at 'uc' field.  */
 };
 
-static inline int
+static inline bool
 is_sigtramp_address (void *nip)
 {
 #ifdef HAVE_SIGTRAMP_RT64
-  if (nip == VDSO_SYMBOL (sigtramp_rt64))
-    return 1;
+  if (nip == GLRO (dl_vdso_sigtramp_rt64))
+    return true;
 #endif
-  return 0;
+  return false;
 }
 
 int
diff --git a/sysdeps/unix/sysv/linux/aarch64/Makefile b/sysdeps/unix/sysv/linux/aarch64/Makefile
index 57bbfeaac6..4bcae85bca 100644
--- a/sysdeps/unix/sysv/linux/aarch64/Makefile
+++ b/sysdeps/unix/sysv/linux/aarch64/Makefile
@@ -5,7 +5,6 @@  shared-only-routines += libc-__read_tp
 endif
 
 ifeq ($(subdir),elf)
-sysdep_routines	     += dl-vdso
 sysdep-rtld-routines += __read_tp
 ifeq ($(build-shared),yes)
 # This is needed for DSO loading from static binaries.
diff --git a/sysdeps/unix/sysv/linux/arm/Makefile b/sysdeps/unix/sysv/linux/arm/Makefile
index d7a2f6a8a7..abdf01f00c 100644
--- a/sysdeps/unix/sysv/linux/arm/Makefile
+++ b/sysdeps/unix/sysv/linux/arm/Makefile
@@ -1,5 +1,4 @@ 
 ifeq ($(subdir),elf)
-sysdep_routines += dl-vdso
 sysdep-rtld-routines += aeabi_read_tp libc-do-syscall
 endif
 
diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.c b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
new file mode 100644
index 0000000000..1069879f1a
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.c
@@ -0,0 +1,81 @@ 
+/* Data for vDSO support.  Linux 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
+   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/>.  */
+
+/* This file is included in three different modes for both static (libc.a)
+   and shared (rtld) modes:
+
+   1. PROCINFO_DECL is defined, meaning we are only interested in
+      declarations.  For static it requires use the extern keywork along with
+      the attribute_relro while for shared it will be embedded in the
+      rtld_global_ro.
+
+   2. PROCINFO_DECL and SHARED are not defined.  Nothing to do, the default
+      zero initializion is suffice.
+
+   3. PROCINFO_DECL is not defined while SHARED is.  Similar to 2., the zero
+      initialization of rtld_global_ro is suffice.  */
+
+#ifndef PROCINFO_CLASS
+# define PROCINFO_CLASS
+#endif
+
+#ifndef SHARED
+# define RELRO attribute_relro
+#else
+# define RELRO
+#endif
+
+#if defined PROCINFO_DECL || !defined SHARED
+# ifdef HAVE_CLOCK_GETTIME_VSYSCALL
+PROCINFO_CLASS int (*_dl_vdso_clock_gettime) (clockid_t,
+					      struct timespec *) RELRO;
+#endif
+# ifdef HAVE_GETTIMEOFDAY_VSYSCALL
+PROCINFO_CLASS int (*_dl_vdso_gettimeofday) (struct timeval *, void *) RELRO;
+#endif
+# ifdef HAVE_TIME_VSYSCALL
+PROCINFO_CLASS time_t (*_dl_vdso_time) (time_t *) RELRO;
+# endif
+# ifdef HAVE_GETCPU_VSYSCALL
+PROCINFO_CLASS int (*_dl_vdso_getcpu) (unsigned *, unsigned *, void *) RELRO;
+# endif
+# ifdef HAVE_CLOCK_GETRES_VSYSCALL
+PROCINFO_CLASS int (*_dl_vdso_clock_getres) (clockid_t,
+					     struct timespec *) RELRO;
+# endif
+
+/* PowerPC specific ones.  */
+# ifdef HAVE_GET_TBFREQ
+PROCINFO_CLASS uint64_t (*_dl_vdso_get_tbfreq)(void) RELRO;
+# endif
+/* The sigtramp are used on powerpc backtrace without using
+   INLINE_VSYSCALL, so there is no need to set their type.  */
+# ifdef HAVE_SIGTRAMP_RT64
+PROCINFO_CLASS void *_dl_vdso_sigtramp_rt64 RELRO;
+# endif
+# ifdef HAVE_SIGTRAMP_RT32
+PROCINFO_CLASS void *_dl_vdso_sigtramp_rt32 RELRO;
+# endif
+# ifdef HAVE_SIGTRAMP_32
+PROCINFO_CLASS void *_dl_vdso_sigtramp_32 RELRO;
+# endif
+#endif
+
+#undef RELRO
+#undef PROCINFO_DECL
+#undef PROCINFO_CLASS
diff --git a/sysdeps/unix/sysv/linux/dl-vdso-setup.h b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
new file mode 100644
index 0000000000..f4e76202fc
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/dl-vdso-setup.h
@@ -0,0 +1,55 @@ 
+/* ELF symbol initialization functions for VDSO objects.  Linux 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
+   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/>.  */
+
+#ifndef _DL_VDSO_INIT_H
+#define _DL_VDSO_INIT_H
+
+/* Initialize the VDSO functions pointers.  */
+static inline void __attribute__ ((always_inline))
+setup_vdso_pointers (void)
+{
+#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
+  GLRO(dl_vdso_clock_gettime) = dl_vdso_vsym (HAVE_CLOCK_GETTIME_VSYSCALL);
+#endif
+#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
+  GLRO(dl_vdso_gettimeofday) = dl_vdso_vsym (HAVE_GETTIMEOFDAY_VSYSCALL);
+#endif
+#ifdef HAVE_TIME_VSYSCALL
+  GLRO(dl_vdso_time) = dl_vdso_vsym (HAVE_TIME_VSYSCALL);
+#endif
+#ifdef HAVE_GETCPU_VSYSCALL
+  GLRO(dl_vdso_getcpu) = dl_vdso_vsym (HAVE_GETCPU_VSYSCALL);
+#endif
+#ifdef HAVE_CLOCK_GETRES_VSYSCALL
+  GLRO(dl_vdso_clock_getres) = dl_vdso_vsym (HAVE_CLOCK_GETRES_VSYSCALL);
+#endif
+#ifdef HAVE_GET_TBFREQ
+  GLRO(dl_vdso_get_tbfreq) = dl_vdso_vsym (HAVE_GET_TBFREQ);
+#endif
+#ifdef HAVE_SIGTRAMP_RT64
+  GLRO(dl_vdso_sigtramp_rt64) = dl_vdso_vsym (HAVE_SIGTRAMP_RT64);
+#endif
+#ifdef HAVE_SIGTRAMP_RT32
+  GLRO(dl_vdso_sigtramp_rt32) = dl_vdso_vsym (HAVE_SIGTRAMP_RT32);
+#endif
+#ifdef HAVE_SIGTRAMP_32
+  GLRO(dl_vdso_sigtramp_32) = dl_vdso_vsym (HAVE_SIGTRAMP_32);
+#endif
+}
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/dl-vdso.c b/sysdeps/unix/sysv/linux/dl-vdso.c
deleted file mode 100644
index 5577f2103c..0000000000
--- a/sysdeps/unix/sysv/linux/dl-vdso.c
+++ /dev/null
@@ -1,48 +0,0 @@ 
-/* ELF symbol resolve functions for VDSO objects.
-   Copyright (C) 2005-2019 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 "config.h"
-#include <ldsodefs.h>
-
-
-void *
-_dl_vdso_vsym (const char *name, const struct r_found_version *vers)
-{
-  struct link_map *map = GLRO (dl_sysinfo_map);
-  void *value = NULL;
-
-
-  if (map != NULL)
-    {
-      /* Use a WEAK REF so we don't error out if the symbol is not found.  */
-      ElfW (Sym) wsym;
-      memset (&wsym, 0, sizeof (ElfW (Sym)));
-      wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
-
-      /* Search the scope of the vdso map.  */
-      const ElfW (Sym) *ref = &wsym;
-      lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref,
-						   map->l_local_scope,
-						   vers, 0, 0, NULL);
-
-      if (ref != NULL)
-	value = DL_SYMBOL_ADDRESS (result, ref);
-    }
-
-  return value;
-}
diff --git a/sysdeps/unix/sysv/linux/dl-vdso.h b/sysdeps/unix/sysv/linux/dl-vdso.h
index 19ffd30c7e..d1e782b81f 100644
--- a/sysdeps/unix/sysv/linux/dl-vdso.h
+++ b/sysdeps/unix/sysv/linux/dl-vdso.h
@@ -22,11 +22,6 @@ 
 #include <ldsodefs.h>
 #include <dl-hash.h>
 
-/* Functions for resolving symbols in the VDSO link map.  */
-extern void *_dl_vdso_vsym (const char *name,
-			    const struct r_found_version *version)
-      attribute_hidden;
-
 /* If the architecture support vDSO it should define which is the expected
    kernel version and hash value through both VDSO_NAME and VDSO_HASH
    (usually defined at architecture sysdep.h).  */
@@ -38,19 +33,26 @@  extern void *_dl_vdso_vsym (const char *name,
 # define VDSO_HASH 0
 #endif
 
+/* Functions for resolving symbols in the VDSO link map.  */
 static inline void *
-get_vdso_symbol (const char *symbol)
+dl_vdso_vsym (const char *name)
 {
+  struct link_map *map = GLRO (dl_sysinfo_map);
+  if (map == NULL)
+    return NULL;
+
+  /* Use a WEAK REF so we don't error out if the symbol is not found.  */
+  ElfW (Sym) wsym = { 0 };
+  wsym.st_info = (unsigned char) ELFW (ST_INFO (STB_WEAK, STT_NOTYPE));
+
   struct r_found_version rfv = { VDSO_NAME, VDSO_HASH, 1, NULL };
-  return _dl_vdso_vsym (symbol, &rfv);
-}
 
-static inline void *
-get_vdso_mangle_symbol (const char *symbol)
-{
-  void *vdsop = get_vdso_symbol (symbol);
-  PTR_MANGLE (vdsop);
-  return vdsop;
+  /* Search the scope of the vdso map.  */
+  const ElfW (Sym) *ref = &wsym;
+  lookup_t result = GLRO (dl_lookup_symbol_x) (name, map, &ref,
+					       map->l_local_scope,
+					       &rfv, 0, 0, NULL);
+  return ref != NULL ? DL_SYMBOL_ADDRESS (result, ref) : NULL;
 }
 
 #endif /* dl-vdso.h */
diff --git a/sysdeps/unix/sysv/linux/gettimeofday.c b/sysdeps/unix/sysv/linux/gettimeofday.c
index 600da6b468..6945be269c 100644
--- a/sysdeps/unix/sysv/linux/gettimeofday.c
+++ b/sysdeps/unix/sysv/linux/gettimeofday.c
@@ -25,6 +25,7 @@ 
 
 # ifdef SHARED
 #  include <dl-vdso.h>
+# include <libc-vdso.h>
 
 static int
 __gettimeofday_syscall (struct timeval *restrict tv, void *restrict tz)
@@ -36,7 +37,7 @@  __gettimeofday_syscall (struct timeval *restrict tv, void *restrict tz)
 
 # undef INIT_ARCH
 # define INIT_ARCH() \
-  void *vdso_gettimeofday = get_vdso_symbol (HAVE_GETTIMEOFDAY_VSYSCALL)
+  void *vdso_gettimeofday = dl_vdso_vsym (HAVE_GETTIMEOFDAY_VSYSCALL)
 libc_ifunc (__gettimeofday,
 	    vdso_gettimeofday ? VDSO_IFUNC_RET (vdso_gettimeofday)
 			      : (void *) __gettimeofday_syscall)
diff --git a/sysdeps/unix/sysv/linux/init-first.c b/sysdeps/unix/sysv/linux/init-first.c
deleted file mode 100644
index d005d13322..0000000000
--- a/sysdeps/unix/sysv/linux/init-first.c
+++ /dev/null
@@ -1,90 +0,0 @@ 
-/* vDSO internal symbols.  Linux generic 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
-   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
-   <http://www.gnu.org/licenses/>.  */
-
-#include <dl-vdso.h>
-#include <libc-vdso.h>
-
-/* vDSO symbol used on clock_gettime implementation.  */
-#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
-int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on clock_gettime64 implementation.  */
-#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
-int (*VDSO_SYMBOL(clock_gettime64)) (clockid_t, struct __timespec64 *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on clock_getres implementation.  */
-#ifdef HAVE_CLOCK_GETRES_VSYSCALL
-int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on gettimeofday implementation.  */
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-int (*VDSO_SYMBOL (gettimeofday)) (struct timeval *, void *)
-  attribute_hidden;
-#endif
-/* vDSO symbol used on GNU extension getcpu implementation.  */
-#ifdef HAVE_GETCPU_VSYSCALL
-long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
-   attribute_hidden;
-#endif
-/* vDSO symbol used on time implementation.  */
-#ifdef HAVE_TIME_VSYSCALL
-time_t (*VDSO_SYMBOL(time)) (time_t *) attribute_hidden;
-#endif
-
-static inline void
-__libc_vdso_platform_setup (void)
-{
-#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
-  VDSO_SYMBOL(clock_gettime)
-    = get_vdso_mangle_symbol (HAVE_CLOCK_GETTIME_VSYSCALL);
-#endif
-
-#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
-  VDSO_SYMBOL(clock_gettime64)
-    = get_vdso_mangle_symbol (HAVE_CLOCK_GETTIME64_VSYSCALL);
-#endif
-
-#ifdef HAVE_CLOCK_GETRES_VSYSCALL
-  VDSO_SYMBOL(clock_getres)
-    = get_vdso_mangle_symbol (HAVE_CLOCK_GETRES_VSYSCALL);
-#endif
-
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-  VDSO_SYMBOL(gettimeofday)
-    = get_vdso_mangle_symbol (HAVE_GETTIMEOFDAY_VSYSCALL);
-#endif
-
-#ifdef HAVE_GETCPU_VSYSCALL
-  VDSO_SYMBOL(getcpu) = get_vdso_mangle_symbol (HAVE_GETCPU_VSYSCALL);
-#endif
-
-#ifdef HAVE_TIME_VSYSCALL
-  VDSO_SYMBOL(time) = get_vdso_mangle_symbol (HAVE_TIME_VSYSCALL);
-#endif
-
-#ifdef VDSO_SETUP_ARCH
-  VDSO_SETUP_ARCH ();
-#endif
-}
-
-#define VDSO_SETUP __libc_vdso_platform_setup
-
-#include <csu/init-first.c>
diff --git a/sysdeps/unix/sysv/linux/libc-vdso.h b/sysdeps/unix/sysv/linux/libc-vdso.h
index c6d505bab3..004faf0a97 100644
--- a/sysdeps/unix/sysv/linux/libc-vdso.h
+++ b/sysdeps/unix/sysv/linux/libc-vdso.h
@@ -19,37 +19,9 @@ 
 #ifndef _LIBC_VDSO_H
 #define _LIBC_VDSO_H
 
-#define VDSO_SYMBOL(__name) __vdso_##__name
-
 /* Adjust the return IFUNC value from a vDSO symbol accordingly required
    by the ELFv1 ABI.  It is used by the architecture to create an ODP
    entry since the kernel vDSO does not provide it.  */
-#ifndef VDSO_IFUNC_RET
-# define VDSO_IFUNC_RET(__value) (__value)
-#endif
+#define VDSO_IFUNC_RET(__value) (__value)
 
-#ifdef HAVE_CLOCK_GETTIME_VSYSCALL
-extern int (*VDSO_SYMBOL(clock_gettime)) (clockid_t, struct timespec *)
-  attribute_hidden;
-#endif
-#ifdef HAVE_CLOCK_GETTIME64_VSYSCALL
-extern int (*VDSO_SYMBOL(clock_gettime64)) (clockid_t, struct __timespec64 *)
-  attribute_hidden;
-#endif
-#ifdef HAVE_CLOCK_GETRES_VSYSCALL
-extern int (*VDSO_SYMBOL(clock_getres)) (clockid_t, struct timespec *)
-  attribute_hidden;
 #endif
-#ifdef HAVE_GETTIMEOFDAY_VSYSCALL
-extern int (*VDSO_SYMBOL (gettimeofday)) (struct timeval *, void *)
-  attribute_hidden;
-#endif
-#ifdef HAVE_GETCPU_VSYSCALL
-extern long int (*VDSO_SYMBOL(getcpu)) (unsigned *, unsigned *, void *)
-  attribute_hidden;
-#endif
-#ifdef HAVE_TIME_VSYSCALL
-extern time_t (*VDSO_SYMBOL(time)) (time_t *) attribute_hidden;
-#endif
-
-#endif /* _LIBC_VDSO_H */
diff --git a/sysdeps/unix/sysv/linux/mips/Makefile b/sysdeps/unix/sysv/linux/mips/Makefile
index 03044e7365..026ba242cf 100644
--- a/sysdeps/unix/sysv/linux/mips/Makefile
+++ b/sysdeps/unix/sysv/linux/mips/Makefile
@@ -60,8 +60,6 @@  ifeq ($(subdir),elf)
 ifeq ($(build-shared),yes)
 # This is needed for DSO loading from static binaries.
 sysdep-dl-routines += dl-static
-
-sysdep_routines += dl-vdso
 endif
 # If the compiler doesn't use GNU.stack note,
 # this test is expected to fail.
diff --git a/sysdeps/unix/sysv/linux/powerpc/Makefile b/sysdeps/unix/sysv/linux/powerpc/Makefile
index 1596238afa..cc2f804d86 100644
--- a/sysdeps/unix/sysv/linux/powerpc/Makefile
+++ b/sysdeps/unix/sysv/linux/powerpc/Makefile
@@ -13,7 +13,6 @@  gen-as-const-headers += ucontext_i.sym
 endif
 
 ifeq ($(subdir),elf)
-sysdep_routines += dl-vdso
 ifeq ($(build-shared),yes)
 # This is needed for DSO loading from static binaries.
 sysdep-dl-routines += dl-static
diff --git a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
index 29b6624b9a..11eb2b126d 100644
--- a/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
+++ b/sysdeps/unix/sysv/linux/powerpc/get_timebase_freq.c
@@ -21,7 +21,7 @@ 
 
 #include <libc-internal.h>
 #include <not-cancel.h>
-#include <libc-vdso.h>
+#include <sysdep-vdso.h>
 
 static uint64_t
 get_timebase_freq_fallback (void)
@@ -101,8 +101,7 @@  uint64_t
 __get_timebase_freq (void)
 {
   /* The vDSO does not have a fallback mechanism (such calling a syscall).  */
-  __typeof (VDSO_SYMBOL (get_tbfreq)) vdsop = VDSO_SYMBOL (get_tbfreq);
-  PTR_DEMANGLE (vdsop);
+  uint64_t (*vdsop)(void) = GLRO(dl_vdso_get_tbfreq);
   if (vdsop == NULL)
     return get_timebase_freq_fallback ();
 
diff --git a/sysdeps/unix/sysv/linux/powerpc/init-first.c b/sysdeps/unix/sysv/linux/powerpc/init-first.c
deleted file mode 100644
index 92a4af83af..0000000000
--- a/sysdeps/unix/sysv/linux/powerpc/init-first.c
+++ /dev/null
@@ -1,50 +0,0 @@ 
-/* Initialization code run first thing by the ELF startup code.  Linux/PowerPC.
-   Copyright (C) 2007-2019 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 <dl-vdso.h>
-#include <libc-vdso.h>
-
-unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void) attribute_hidden;
-#if defined(__PPC64__) || defined(__powerpc64__)
-void *VDSO_SYMBOL(sigtramp_rt64) attribute_hidden;
-#else
-void *VDSO_SYMBOL(sigtramp32) attribute_hidden;
-void *VDSO_SYMBOL(sigtramp_rt32) attribute_hidden;
-#endif
-
-static inline void
-__libc_vdso_platform_setup_arch (void)
-{
-  VDSO_SYMBOL (get_tbfreq) = get_vdso_mangle_symbol (HAVE_GET_TBFREQ);
-
-  /* PPC64 uses only one signal trampoline symbol, while PPC32 will use
-     two depending if SA_SIGINFO is used (__kernel_sigtramp_rt32) or not
-     (__kernel_sigtramp32).
-     There is no need to pointer mangle these symbol because they will
-     used only for pointer comparison.  */
-#if defined(__PPC64__) || defined(__powerpc64__)
-  VDSO_SYMBOL(sigtramp_rt64) =  get_vdso_symbol (HAVE_SIGTRAMP_RT64);
-#else
-  VDSO_SYMBOL(sigtramp32) = get_vdso_symbol (HAVE_SIGTRAMP_32);
-  VDSO_SYMBOL(sigtramp_rt32) = get_vdso_symbol (HAVE_SIGTRAMP_RT32);
-#endif
-}
-
-#define VDSO_SETUP_ARCH __libc_vdso_platform_setup_arch
-
-#include <sysdeps/unix/sysv/linux/init-first.c>
diff --git a/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
index cb7da3b289..adc06d48b0 100644
--- a/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
+++ b/sysdeps/unix/sysv/linux/powerpc/libc-vdso.h
@@ -54,14 +54,4 @@ 
 # define VDSO_IFUNC_RET(value)  ((void *) (value))
 #endif
 
-#include_next <libc-vdso.h>
-
-extern unsigned long long (*VDSO_SYMBOL(get_tbfreq)) (void);
-#if defined(__PPC64__) || defined(__powerpc64__)
-extern void *VDSO_SYMBOL(sigtramp_rt64);
-#else
-extern void *VDSO_SYMBOL(sigtramp32);
-extern void *VDSO_SYMBOL(sigtramp_rt32);
-#endif
-
 #endif /* _LIBC_VDSO_H */
diff --git a/sysdeps/unix/sysv/linux/riscv/Makefile b/sysdeps/unix/sysv/linux/riscv/Makefile
index b7ad31885c..301b082398 100644
--- a/sysdeps/unix/sysv/linux/riscv/Makefile
+++ b/sysdeps/unix/sysv/linux/riscv/Makefile
@@ -1,7 +1,3 @@ 
-ifeq ($(subdir),elf)
-sysdep_routines	+= dl-vdso
-endif
-
 ifeq ($(subdir),misc)
 sysdep_headers += sys/cachectl.h
 sysdep_routines += flush-icache
diff --git a/sysdeps/unix/sysv/linux/riscv/flush-icache.c b/sysdeps/unix/sysv/linux/riscv/flush-icache.c
index c5bd60d9c2..e967e40deb 100644
--- a/sysdeps/unix/sysv/linux/riscv/flush-icache.c
+++ b/sysdeps/unix/sysv/linux/riscv/flush-icache.c
@@ -38,7 +38,7 @@  __riscv_flush_icache_syscall (void *start, void *end, unsigned long int flags)
 static func_type
 __lookup_riscv_flush_icache (void)
 {
-  func_type func = get_vdso_symbol ("__vdso_flush_icache");
+  func_type func = dl_vdso_vsym ("__vdso_flush_icache");
 
   /* If there is no vDSO entry then call the system call directly.  All Linux
      versions provide the vDSO entry, but QEMU's user-mode emulation doesn't
diff --git a/sysdeps/unix/sysv/linux/s390/Makefile b/sysdeps/unix/sysv/linux/s390/Makefile
index 77f38523b5..d9db1b5422 100644
--- a/sysdeps/unix/sysv/linux/s390/Makefile
+++ b/sysdeps/unix/sysv/linux/s390/Makefile
@@ -11,10 +11,6 @@  ifeq ($(subdir),stdlib)
 gen-as-const-headers += ucontext_i.sym
 endif
 
-ifeq ($(subdir),elf)
-sysdep_routines += dl-vdso
-endif
-
 ifeq ($(subdir),nptl)
 libpthread-sysdep_routines += elision-lock elision-unlock elision-timed \
 			      elision-trylock
diff --git a/sysdeps/unix/sysv/linux/sparc/Makefile b/sysdeps/unix/sysv/linux/sparc/Makefile
index fb3ee5b8a1..b0d182a439 100644
--- a/sysdeps/unix/sysv/linux/sparc/Makefile
+++ b/sysdeps/unix/sysv/linux/sparc/Makefile
@@ -7,10 +7,6 @@  librt-routines += rt-sysdep
 librt-shared-only-routines += rt-sysdep
 endif
 
-ifeq ($(subdir),elf)
-sysdep_routines += dl-vdso
-endif
-
 ifeq ($(subdir),sysvipc)
 sysdep_routines += getshmlba
 endif
diff --git a/sysdeps/unix/sysv/linux/sysdep-vdso.h b/sysdeps/unix/sysv/linux/sysdep-vdso.h
index 76a211e39b..772313f97e 100644
--- a/sysdeps/unix/sysv/linux/sysdep-vdso.h
+++ b/sysdeps/unix/sysv/linux/sysdep-vdso.h
@@ -19,8 +19,7 @@ 
 #ifndef SYSDEP_VDSO_LINUX_H
 # define SYSDEP_VDSO_LINUX_H
 
-#include <dl-vdso.h>
-#include <libc-vdso.h>
+#include <ldsodefs.h>
 
 #ifndef INTERNAL_VSYSCALL_CALL
 # define INTERNAL_VSYSCALL_CALL(funcptr, err, nr, args...)		      \
@@ -34,8 +33,7 @@ 
     INTERNAL_SYSCALL_DECL (sc_err);					      \
     long int sc_ret;							      \
 									      \
-    __typeof (__vdso_##name) vdsop = __vdso_##name;			      \
-    PTR_DEMANGLE (vdsop);						      \
+    __typeof (GLRO(dl_vdso_##name)) vdsop = GLRO(dl_vdso_##name);	      \
     if (vdsop != NULL)							      \
       {									      \
 	sc_ret = INTERNAL_VSYSCALL_CALL (vdsop, sc_err, nr, ##args);	      \
diff --git a/sysdeps/unix/sysv/linux/time.c b/sysdeps/unix/sysv/linux/time.c
index 0598958c9c..a7e4cbeb96 100644
--- a/sysdeps/unix/sysv/linux/time.c
+++ b/sysdeps/unix/sysv/linux/time.c
@@ -25,6 +25,7 @@ 
 
 #ifdef SHARED
 # include <dl-vdso.h>
+# include <libc-vdso.h>
 
 static time_t
 time_syscall (time_t *t)
@@ -34,7 +35,7 @@  time_syscall (time_t *t)
 
 # undef INIT_ARCH
 # define INIT_ARCH() \
-  void *vdso_time = get_vdso_symbol (HAVE_TIME_VSYSCALL);
+  void *vdso_time = dl_vdso_vsym (HAVE_TIME_VSYSCALL);
 libc_ifunc (time,
 	    vdso_time ? VDSO_IFUNC_RET (vdso_time)
 		      : (void *) time_syscall);
diff --git a/sysdeps/unix/sysv/linux/x86/Makefile b/sysdeps/unix/sysv/linux/x86/Makefile
index 02ca36c6d2..b23b532590 100644
--- a/sysdeps/unix/sysv/linux/x86/Makefile
+++ b/sysdeps/unix/sysv/linux/x86/Makefile
@@ -20,10 +20,6 @@  CFLAGS-elision-timed.c += -mrtm
 CFLAGS-elision-trylock.c += -mrtm
 endif
 
-ifeq ($(subdir),elf)
-sysdep_routines += dl-vdso
-endif
-
 ifeq ($(subdir),setjmp)
 tests += tst-saved_mask-1
 endif