diff mbox series

V2 [PATCH 2/2] Add C wrappers for prctl/process_vm_readv/process_vm_writev [BZ #25810]

Message ID 20200429152017.GA3811691@gmail.com
State New
Headers show
Series V2 [PATCH 2/2] Add C wrappers for prctl/process_vm_readv/process_vm_writev [BZ #25810] | expand

Commit Message

H.J. Lu April 29, 2020, 3:20 p.m. UTC 
On Wed, Apr 29, 2020 at 04:55:43PM +0200, Florian Weimer wrote:
> * H. J. Lu:
> 
> > diff --git a/sysdeps/unix/sysv/linux/prctl.c b/sysdeps/unix/sysv/linux/prctl.c
> > new file mode 100644
> > index 0000000000..e0e5ef4e47
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/prctl.c
> > @@ -0,0 +1,39 @@
> > +/* prctl - Linux specific syscall.
> > +   Copyright (C) 2020 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 <unistd.h>
> > +#include <sysdep.h>
> > +#include <errno.h>
> > +
> > +extern int prctl (int, unsigned long, unsigned long, unsigned long,
> > +		  unsigned long);
> > +hidden_proto (prctl)
> > +extern int __prctl (int, unsigned long, unsigned long, unsigned long,
> > +		    unsigned long);
> > +hidden_proto (__prctl)
> > +
> > +int
> > +__prctl (int option, unsigned long arg2, unsigned long arg3,
> > +	 unsigned long arg4, unsigned long arg5)
> 
> unsigned long int everywhere.

Fixed.

> 
> > +{
> > +  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
> > +}
> > +
> > +hidden_def (__prctl)
> > +weak_alias (__prctl, prctl)
> > +hidden_weak (prctl)
> 
> Can't you use libc_hidden_proto in include/sys/prctl.h and
> libc_hidden_proto here?
> 

Since include/sys/prctl.h has

extern int __prctl (int __option, ...);

it can't be used.

> 
> > diff --git a/sysdeps/unix/sysv/linux/process_vm_readv.c b/sysdeps/unix/sysv/linux/process_vm_readv.c
> > new file mode 100644
> > index 0000000000..1e711abe43
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/process_vm_readv.c
> > @@ -0,0 +1,32 @@
> > +/* process_vm_readv - Linux specific syscall.
> > +   Copyright (C) 2020 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 <unistd.h>
> > +#include <sysdep.h>
> > +#include <errno.h>
> > +#include <sys/uio.h>
> > +
> > +ssize_t
> > +process_vm_readv (pid_t pid, const struct iovec *local_iov,
> > +		  unsigned long liovcnt, const struct iovec *remote_iov,
> > +		  unsigned long riovcnt, unsigned long flags)
> > +{
> > +  return INLINE_SYSCALL_CALL (process_vm_readv, pid, local_iov,
> > +			      liovcnt, remote_iov, riovcnt, flags);
> > +}
> 
> Likewise, unsigned long int.

Fixed.
 
> > +
> > diff --git a/sysdeps/unix/sysv/linux/process_vm_writev.c b/sysdeps/unix/sysv/linux/process_vm_writev.c
> > new file mode 100644
> > index 0000000000..e41058750b
> > --- /dev/null
> > +++ b/sysdeps/unix/sysv/linux/process_vm_writev.c
> > @@ -0,0 +1,32 @@
> > +/* process_vm_writev - Linux specific syscall.
> > +   Copyright (C) 2020 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 <unistd.h>
> > +#include <sysdep.h>
> > +#include <errno.h>
> > +#include <sys/uio.h>
> > +
> > +ssize_t
> > +process_vm_writev (pid_t pid, const struct iovec *local_iov,
> > +		   unsigned long liovcnt, const struct iovec *remote_iov,
> > +		   unsigned long riovcnt, unsigned long flags)
> > +{
> > +  return INLINE_SYSCALL_CALL (process_vm_writev, pid, local_iov,
> > +			      liovcnt, remote_iov, riovcnt, flags);
> > +}
> 
> Likewise.

Fixed.

> 
> (I trust the indentation is only wrong in the patch, it's okay when
> applied.)
> 

It is due to spaces vs tab.  The indentation is OK.

Ok for master?

Thanks.

H.J.
---
Since the the U marker can only be applied to 2 unsigned long arguments,
add a C wrapper for prctl, process_vm_readv and process_vm_writev syscals
which have more than 2 unsigned long arguments.
---
 sysdeps/unix/sysv/linux/Makefile            |  3 +-
 sysdeps/unix/sysv/linux/prctl.c             | 39 +++++++++++++++++++++
 sysdeps/unix/sysv/linux/process_vm_readv.c  | 33 +++++++++++++++++
 sysdeps/unix/sysv/linux/process_vm_writev.c | 33 +++++++++++++++++
 sysdeps/unix/sysv/linux/syscalls.list       |  3 --
 5 files changed, 107 insertions(+), 4 deletions(-)
 create mode 100644 sysdeps/unix/sysv/linux/prctl.c
 create mode 100644 sysdeps/unix/sysv/linux/process_vm_readv.c
 create mode 100644 sysdeps/unix/sysv/linux/process_vm_writev.c

Comments

Florian Weimer April 29, 2020, 3:22 p.m. UTC | #1 
* H. J. Lu:

>> > +{
>> > +  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
>> > +}
>> > +
>> > +hidden_def (__prctl)
>> > +weak_alias (__prctl, prctl)
>> > +hidden_weak (prctl)
>> 
>> Can't you use libc_hidden_proto in include/sys/prctl.h and
>> libc_hidden_proto here?
>> 
>
> Since include/sys/prctl.h has
>
> extern int __prctl (int __option, ...);
>
> it can't be used.

I still don't get it.  What happens if you use libc_hidden_proto and
libc_hidden_def?

> Since the the U marker can only be applied to 2 unsigned long arguments,
> add a C wrapper for prctl, process_vm_readv and process_vm_writev syscals
> which have more than 2 unsigned long arguments.

Please add that syscalls.list reference.  Thanks.

Florian
H.J. Lu April 29, 2020, 3:29 p.m. UTC | #2 
On Wed, Apr 29, 2020 at 8:22 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> >> > +{
> >> > +  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
> >> > +}
> >> > +
> >> > +hidden_def (__prctl)
> >> > +weak_alias (__prctl, prctl)
> >> > +hidden_weak (prctl)
> >>
> >> Can't you use libc_hidden_proto in include/sys/prctl.h and
> >> libc_hidden_proto here?
> >>
> >
> > Since include/sys/prctl.h has
> >
> > extern int __prctl (int __option, ...);
> >
> > it can't be used.
>
> I still don't get it.  What happens if you use libc_hidden_proto and
> libc_hidden_def?

With

extern int __prctl (int __option, ...);
libc_hidden_proto (__prctl)
libc_hidden_proto (prctl)

and

#include <unistd.h>
#include <sysdep.h>
#include <errno.h>
#include <sys/prctl.h>

int
__prctl (int option, unsigned long int arg2, unsigned long int arg3,
unsigned long int arg4, unsigned long int arg5)
{
  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
}

libc_hidden_def (__prctl)
weak_alias (__prctl, prctl)
hidden_weak (prctl)

I got

../sysdeps/unix/sysv/linux/prctl.c:25:1: error: conflicting types for ‘__prctl’
   25 | __prctl (int option, unsigned long int arg2, unsigned long int arg3,
      | ^~~~~~~
In file included from <command-line>:
../include/sys/prctl.h:7:20: note: previous declaration of ‘__prctl’ was here
    7 | libc_hidden_proto (__prctl)
      |                    ^~~~~~~
./../include/libc-symbols.h:541:33: note: in definition of macro
‘__hidden_proto’
  541 |   extern thread __typeof (name) name __asm__ (__hidden_asmname
(#internal)) \
      |                                 ^~~~
./../include/libc-symbols.h:624:44: note: in expansion of macro ‘hidden_proto’
  624 | # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
      |                                            ^~~~~~~~~~~~
../include/sys/prctl.h:7:1: note: in expansion of macro ‘libc_hidden_proto’
    7 | libc_hidden_proto (__prctl)
      | ^~~~~~~~~~~~~~~~~
../sysdeps/unix/sysv/linux/prctl.c:32:22: error: conflicting types for ‘prctl’
   32 | weak_alias (__prctl, prctl)
      |                      ^~~~~
./../include/libc-symbols.h:152:26: note: in definition of macro ‘_weak_alias’
  152 |   extern __typeof (name) aliasname __attribute__ ((weak, alias
(#name))) \
      |                          ^~~~~~~~~
../sysdeps/unix/sysv/linux/prctl.c:32:1: note: in expansion of macro
‘weak_alias’
   32 | weak_alias (__prctl, prctl)
      | ^~~~~~~~~~
../include/sys/prctl.h:8:20: note: previous declaration of ‘prctl’ was here
    8 | libc_hidden_proto (prctl)
      |                    ^~~~~
./../include/libc-symbols.h:541:33: note: in definition of macro
‘__hidden_proto’
  541 |   extern thread __typeof (name) name __asm__ (__hidden_asmname
(#internal)) \
      |                                 ^~~~
./../include/libc-symbols.h:624:44: note: in expansion of macro ‘hidden_proto’
  624 | # define libc_hidden_proto(name, attrs...) hidden_proto (name, ##attrs)
      |                                            ^~~~~~~~~~~~
../include/sys/prctl.h:8:1: note: in expansion of macro ‘libc_hidden_proto’
    8 | libc_hidden_proto (prctl)
      | ^~~~~~~~~~~~~~~~~
./../include/libc-symbols.h:552:33: error: ‘__EI___prctl’ aliased to
undefined symbol ‘__GI___prctl’
  552 |   extern thread __typeof (name) __EI_##name \
      |                                 ^~~~~
./../include/libc-symbols.h:548:3: note: in expansion of macro ‘__hidden_ver2’
  548 |   __hidden_ver2 (, local, internal, name)
      |   ^~~~~~~~~~~~~
./../include/libc-symbols.h:557:29: note: in expansion of macro ‘__hidden_ver1’
  557 | #  define hidden_def(name)  __hidden_ver1(__GI_##name, name, name);
      |                             ^~~~~~~~~~~~~
./../include/libc-symbols.h:626:32: note: in expansion of macro ‘hidden_def’
  626 | # define libc_hidden_def(name) hidden_def (name)
      |                                ^~~~~~~~~~
../sysdeps/unix/sysv/linux/prctl.c:31:1: note: in expansion of macro
‘libc_hidden_def’
   31 | libc_hidden_def (__prctl)
      | ^~~~~~~~~~~~~~~
./../include/libc-symbols.h:552:33: error: ‘__EI_prctl’ aliased to
undefined symbol ‘__GI_prctl’
  552 |   extern thread __typeof (name) __EI_##name \
      |                                 ^~~~~
./../include/libc-symbols.h:548:3: note: in expansion of macro ‘__hidden_ver2’
  548 |   __hidden_ver2 (, local, internal, name)
      |   ^~~~~~~~~~~~~
./../include/libc-symbols.h:562:2: note: in expansion of macro ‘__hidden_ver1’
  562 |  __hidden_ver1(__GI_##name, name, name) __attribute__((weak));
      |  ^~~~~~~~~~~~~
../sysdeps/unix/sysv/linux/prctl.c:33:1: note: in expansion of macro
‘hidden_weak’
   33 | hidden_weak (prctl)
      | ^~~~~~~~~~~

> > Since the the U marker can only be applied to 2 unsigned long arguments,
> > add a C wrapper for prctl, process_vm_readv and process_vm_writev syscals
> > which have more than 2 unsigned long arguments.
>
> Please add that syscalls.list reference.  Thanks.
>

I have

---
Since the the U marker can only be applied to 2 unsigned long arguments
in syscalls.list files, add a C wrapper for prctl, process_vm_readv and
process_vm_writev syscals which have more than 2 unsigned long arguments.
---
Andreas Schwab April 29, 2020, 3:32 p.m. UTC | #3 
On Apr 29 2020, H.J. Lu via Libc-alpha wrote:

>> > +int
>> > +__prctl (int option, unsigned long arg2, unsigned long arg3,
>> > +	 unsigned long arg4, unsigned long arg5)
>> 
>> unsigned long int everywhere.
>
> Fixed.
>
>> 
>> > +{
>> > +  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
>> > +}
>> > +
>> > +hidden_def (__prctl)
>> > +weak_alias (__prctl, prctl)
>> > +hidden_weak (prctl)
>> 
>> Can't you use libc_hidden_proto in include/sys/prctl.h and
>> libc_hidden_proto here?
>> 
>
> Since include/sys/prctl.h has
>
> extern int __prctl (int __option, ...);
>
> it can't be used.

You cannot implement a function declared as varargs with a non-varargs
definition.

Andreas.
Florian Weimer April 29, 2020, 3:35 p.m. UTC | #4 
* H. J. Lu:

> With
>
> extern int __prctl (int __option, ...);
> libc_hidden_proto (__prctl)
> libc_hidden_proto (prctl)
>
> and
>
> #include <unistd.h>
> #include <sysdep.h>
> #include <errno.h>
> #include <sys/prctl.h>
>
> int
> __prctl (int option, unsigned long int arg2, unsigned long int arg3,
> unsigned long int arg4, unsigned long int arg5)
> {
>   return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
> }
>
> libc_hidden_def (__prctl)
> weak_alias (__prctl, prctl)
> hidden_weak (prctl)

Please try:

extern int __prctl (int __option, ...);
libc_hidden_proto (__prctl)

And:

int
__prctl (int option, unsigned long int arg2, unsigned long int arg3,
unsigned long int arg4, unsigned long int arg5)
{
  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
}
libc_hidden_def (__prctl)
strong_alias (__prctl, prctl)

Internal users should always use __prctl to avoid linknamespace
failures, so there are no callers of prctl and we don't need a hidden
alias for it.

>> > Since the the U marker can only be applied to 2 unsigned long arguments,
>> > add a C wrapper for prctl, process_vm_readv and process_vm_writev syscals
>> > which have more than 2 unsigned long arguments.
>>
>> Please add that syscalls.list reference.  Thanks.
>>
>
> I have
>
> ---
> Since the the U marker can only be applied to 2 unsigned long arguments
> in syscalls.list files, add a C wrapper for prctl, process_vm_readv and
> process_vm_writev syscals which have more than 2 unsigned long arguments.
> ---

Nice.

Thanks,
Florian
H.J. Lu April 29, 2020, 3:36 p.m. UTC | #5 
On Wed, Apr 29, 2020 at 8:32 AM Andreas Schwab <schwab@linux-m68k.org> wrote:
>
> On Apr 29 2020, H.J. Lu via Libc-alpha wrote:
>
> >> > +int
> >> > +__prctl (int option, unsigned long arg2, unsigned long arg3,
> >> > +   unsigned long arg4, unsigned long arg5)
> >>
> >> unsigned long int everywhere.
> >
> > Fixed.
> >
> >>
> >> > +{
> >> > +  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
> >> > +}
> >> > +
> >> > +hidden_def (__prctl)
> >> > +weak_alias (__prctl, prctl)
> >> > +hidden_weak (prctl)
> >>
> >> Can't you use libc_hidden_proto in include/sys/prctl.h and
> >> libc_hidden_proto here?
> >>
> >
> > Since include/sys/prctl.h has
> >
> > extern int __prctl (int __option, ...);
> >
> > it can't be used.
>
> You cannot implement a function declared as varargs with a non-varargs
> definition.

True.  There is a separate bug:

https://sourceware.org/bugzilla/show_bug.cgi?id=25896
Florian Weimer April 29, 2020, 3:41 p.m. UTC | #6 
* Florian Weimer:

>> extern int __prctl (int __option, ...);
>> libc_hidden_proto (__prctl)
>> libc_hidden_proto (prctl)
>>
>> and
>>
>> #include <unistd.h>
>> #include <sysdep.h>
>> #include <errno.h>
>> #include <sys/prctl.h>
>>
>> int
>> __prctl (int option, unsigned long int arg2, unsigned long int arg3,
>> unsigned long int arg4, unsigned long int arg5)
>> {
>>   return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
>> }
>>
>> libc_hidden_def (__prctl)
>> weak_alias (__prctl, prctl)
>> hidden_weak (prctl)
>
> Please try:
>
> extern int __prctl (int __option, ...);
> libc_hidden_proto (__prctl)
>
> And:
>
> int
> __prctl (int option, unsigned long int arg2, unsigned long int arg3,
> unsigned long int arg4, unsigned long int arg5)
> {
>   return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
> }
> libc_hidden_def (__prctl)
> strong_alias (__prctl, prctl)
>
> Internal users should always use __prctl to avoid linknamespace
> failures, so there are no callers of prctl and we don't need a hidden
> alias for it.

My bad.  I see it know.  It's the variadic/non-variadic mismatch.

For the open family of functions, we actually use <stdarg.h> and try to
match the actual argument list.  This has caused bugs, so I don't
recommend it.

For fcntl, we unconditionally access the optional arguments, also with
<stdarg.h>.  This avoids the bug.  Likewise for ptrace.

I think it's safe for the ABIs we support to implement a variadic
function with a non-variadic one.  It's needed for implicit function
declaration support.  (The converse is definitely unsafe and causes
stack corruption on some targets.)

So perhaps use <stdarg.h> for prctl as well?

Thanks,
Florian
Florian Weimer April 29, 2020, 3:43 p.m. UTC | #7 
* H. J. Lu:

> On Wed, Apr 29, 2020 at 8:32 AM Andreas Schwab <schwab@linux-m68k.org> wrote:
>>
>> On Apr 29 2020, H.J. Lu via Libc-alpha wrote:
>>
>> >> > +int
>> >> > +__prctl (int option, unsigned long arg2, unsigned long arg3,
>> >> > +   unsigned long arg4, unsigned long arg5)
>> >>
>> >> unsigned long int everywhere.
>> >
>> > Fixed.
>> >
>> >>
>> >> > +{
>> >> > +  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
>> >> > +}
>> >> > +
>> >> > +hidden_def (__prctl)
>> >> > +weak_alias (__prctl, prctl)
>> >> > +hidden_weak (prctl)
>> >>
>> >> Can't you use libc_hidden_proto in include/sys/prctl.h and
>> >> libc_hidden_proto here?
>> >>
>> >
>> > Since include/sys/prctl.h has
>> >
>> > extern int __prctl (int __option, ...);
>> >
>> > it can't be used.
>>
>> You cannot implement a function declared as varargs with a non-varargs
>> definition.
>
> True.  There is a separate bug:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=25896

I suggest to drop prctl from process_vm_*v fix and commit only the
latter now.

Thanks,
Florian
H.J. Lu April 29, 2020, 3:52 p.m. UTC | #8 
On Wed, Apr 29, 2020 at 8:43 AM Florian Weimer <fweimer@redhat.com> wrote:
>
> * H. J. Lu:
>
> > On Wed, Apr 29, 2020 at 8:32 AM Andreas Schwab <schwab@linux-m68k.org> wrote:
> >>
> >> On Apr 29 2020, H.J. Lu via Libc-alpha wrote:
> >>
> >> >> > +int
> >> >> > +__prctl (int option, unsigned long arg2, unsigned long arg3,
> >> >> > +   unsigned long arg4, unsigned long arg5)
> >> >>
> >> >> unsigned long int everywhere.
> >> >
> >> > Fixed.
> >> >
> >> >>
> >> >> > +{
> >> >> > +  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
> >> >> > +}
> >> >> > +
> >> >> > +hidden_def (__prctl)
> >> >> > +weak_alias (__prctl, prctl)
> >> >> > +hidden_weak (prctl)
> >> >>
> >> >> Can't you use libc_hidden_proto in include/sys/prctl.h and
> >> >> libc_hidden_proto here?
> >> >>
> >> >
> >> > Since include/sys/prctl.h has
> >> >
> >> > extern int __prctl (int __option, ...);
> >> >
> >> > it can't be used.
> >>
> >> You cannot implement a function declared as varargs with a non-varargs
> >> definition.
> >
> > True.  There is a separate bug:
> >
> > https://sourceware.org/bugzilla/show_bug.cgi?id=25896
>
> I suggest to drop prctl from process_vm_*v fix and commit only the
> latter now.
>
> Thanks,
> Florian
>

Sounds good.  I will submit a separate patch for prctl later.

This is I am going to check in.

Thanks.
Florian Weimer April 29, 2020, 3:55 p.m. UTC | #9 
* H. J. Lu:

> Sounds good.  I will submit a separate patch for prctl later.
>
> This is I am going to check in.

Yes, looks good, thanks.

Florian
diff mbox series

Patch

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 089a4899d5..1d9a8d3cdb 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -59,7 +59,8 @@  sysdep_routines += adjtimex clone umount umount2 readahead sysctl \
 		   eventfd eventfd_read eventfd_write prlimit \
 		   personality epoll_wait tee vmsplice splice \
 		   open_by_handle_at mlock2 pkey_mprotect pkey_set pkey_get \
-		   timerfd_gettime timerfd_settime
+		   timerfd_gettime timerfd_settime prctl \
+		   process_vm_readv process_vm_writev
 
 CFLAGS-gethostid.c = -fexceptions
 CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables
diff --git a/sysdeps/unix/sysv/linux/prctl.c b/sysdeps/unix/sysv/linux/prctl.c
new file mode 100644
index 0000000000..6a9c1a8fbf
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/prctl.c
@@ -0,0 +1,39 @@ 
+/* prctl - Linux specific syscall.
+   Copyright (C) 2020 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 <unistd.h>
+#include <sysdep.h>
+#include <errno.h>
+
+extern int prctl (int, unsigned long int, unsigned long int,
+		  unsigned long int, unsigned long int);
+hidden_proto (prctl)
+extern int __prctl (int, unsigned long int, unsigned long int,
+		    unsigned long int, unsigned long int);
+hidden_proto (__prctl)
+
+int
+__prctl (int option, unsigned long int arg2, unsigned long int arg3,
+	 unsigned long int arg4, unsigned long int arg5)
+{
+  return INLINE_SYSCALL_CALL (prctl, option, arg2, arg3, arg4, arg5);
+}
+
+hidden_def (__prctl)
+weak_alias (__prctl, prctl)
+hidden_weak (prctl)
diff --git a/sysdeps/unix/sysv/linux/process_vm_readv.c b/sysdeps/unix/sysv/linux/process_vm_readv.c
new file mode 100644
index 0000000000..dca826b679
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/process_vm_readv.c
@@ -0,0 +1,33 @@ 
+/* process_vm_readv - Linux specific syscall.
+   Copyright (C) 2020 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 <unistd.h>
+#include <sysdep.h>
+#include <errno.h>
+#include <sys/uio.h>
+
+ssize_t
+process_vm_readv (pid_t pid, const struct iovec *local_iov,
+		  unsigned long int liovcnt,
+		  const struct iovec *remote_iov,
+		  unsigned long int riovcnt, unsigned long int flags)
+{
+  return INLINE_SYSCALL_CALL (process_vm_readv, pid, local_iov,
+			      liovcnt, remote_iov, riovcnt, flags);
+}
+
diff --git a/sysdeps/unix/sysv/linux/process_vm_writev.c b/sysdeps/unix/sysv/linux/process_vm_writev.c
new file mode 100644
index 0000000000..15748451aa
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/process_vm_writev.c
@@ -0,0 +1,33 @@ 
+/* process_vm_writev - Linux specific syscall.
+   Copyright (C) 2020 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 <unistd.h>
+#include <sysdep.h>
+#include <errno.h>
+#include <sys/uio.h>
+
+ssize_t
+process_vm_writev (pid_t pid, const struct iovec *local_iov,
+		   unsigned long int liovcnt,
+		   const struct iovec *remote_iov,
+		   unsigned long int riovcnt, unsigned long int flags)
+{
+  return INLINE_SYSCALL_CALL (process_vm_writev, pid, local_iov,
+			      liovcnt, remote_iov, riovcnt, flags);
+}
+
diff --git a/sysdeps/unix/sysv/linux/syscalls.list b/sysdeps/unix/sysv/linux/syscalls.list
index 5b4e205934..1d8893d1b8 100644
--- a/sysdeps/unix/sysv/linux/syscalls.list
+++ b/sysdeps/unix/sysv/linux/syscalls.list
@@ -43,7 +43,6 @@  nfsservctl	EXTRA	nfsservctl	i:ipp	__compat_nfsservctl	nfsservctl@GLIBC_2.0:GLIBC
 pipe		-	pipe		i:f	__pipe		pipe
 pipe2		-	pipe2		i:fi	__pipe2		pipe2
 pivot_root	EXTRA	pivot_root	i:ss	pivot_root
-prctl		EXTRA	prctl		i:iiiii	__prctl		prctl
 query_module	EXTRA	query_module	i:sipip	__compat_query_module	query_module@GLIBC_2.0:GLIBC_2.23
 quotactl	EXTRA	quotactl	i:isip	quotactl
 remap_file_pages -	remap_file_pages i:pUiUi	__remap_file_pages remap_file_pages
@@ -98,8 +97,6 @@  name_to_handle_at EXTRA	name_to_handle_at i:isppi name_to_handle_at
 
 setns		EXTRA	setns		i:ii	setns
 
-process_vm_readv EXTRA	process_vm_readv i:ipipii process_vm_readv
-process_vm_writev EXTRA	process_vm_writev i:ipipii process_vm_writev
 memfd_create    EXTRA	memfd_create	i:si    memfd_create
 pkey_alloc	EXTRA	pkey_alloc	i:ii	pkey_alloc
 pkey_free	EXTRA	pkey_free	i:i	pkey_free