diff mbox

[3/4] Consolidate pread/pread64 implementations

Message ID 1456240627-18774-4-git-send-email-adhemerval.zanella@linaro.org
State New
Headers show

Commit Message

Adhemerval Zanella Netto Feb. 23, 2016, 3:17 p.m. UTC
From: Adhemerval Zanella <adhemerval.zanella@linaro.com>

This patch consolidates all the pread/pread64 implementation for Linux
in only one (sysdeps/unix/sysv/linux/pread.c).  It also removes the
syscall from the auto-generation using assembly macros.

For pread{64} offset argument placement the new SYSCALL_LL{64} macro
is used.  For pread ports that do not define __NR_pread will use
__NR_pread64 and for pread64 ports that dot define __NR_pread64 will
use __NR_pread for the syscall.

Checked on x86_64, x32, i386, aarch64, and ppc64le.

	* sysdeps/unix/sysv/linux/arm/pread.c: Remove file.
	* sysdeps/unix/sysv/linux/arm/pread64.c: Likewise.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/pread.c: Likewise.
	* sysdeps/unix/sysv/linux/generic/wordsize-32/pread64.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c: Likewise,
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/pread64.c: Likewise.
	* sysdeps/unix/sysv/linux/wordsize-64/pread64.c: Likewise.
	* sysdeps/unix/sysv/linux/wordsize-64/syscalls.list (pread): Remove
	syscall generation.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
	[__NR_pread64] (__NR_pread): Remove define.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h:
	[__NR_pread64] (__NR_pread): Likewise.
	* sysdeps/unix/sysv/linux/pread.c [__NR_pread64] (__NR_pread): Remove
	define.
	(__libc_pread): Use SYSCALL_LL macro on offset argument.
	* sysdeps/unix/sysv/linux/pread64.c [__NR_pread64] (__NR_pread):
	Remove define.
	(__libc_pread64): Use SYSCALL_LL64 macro on offset argument.
	* sysdeps/unix/sysv/linux/sh/pread.c: Rewrite using default
	Linux implementation as base.
	* sysdeps/unix/sysv/linux/sh/pread64.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/pread.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/pread64.c: Likewise.
---
 sysdeps/unix/sysv/linux/arm/pread.c                | 36 --------------------
 sysdeps/unix/sysv/linux/arm/pread64.c              | 37 ---------------------
 .../unix/sysv/linux/generic/wordsize-32/pread.c    | 37 ---------------------
 .../unix/sysv/linux/generic/wordsize-32/pread64.c  | 34 -------------------
 sysdeps/unix/sysv/linux/mips/pread.c               | 38 ++++------------------
 sysdeps/unix/sysv/linux/mips/pread64.c             | 34 ++++---------------
 sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c  | 34 -------------------
 .../unix/sysv/linux/powerpc/powerpc32/pread64.c    | 35 --------------------
 sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h |  7 ----
 sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h |  7 ----
 sysdeps/unix/sysv/linux/pread.c                    | 25 ++++----------
 sysdeps/unix/sysv/linux/pread64.c                  | 23 ++++++-------
 sysdeps/unix/sysv/linux/sh/pread.c                 | 30 +++--------------
 sysdeps/unix/sysv/linux/sh/pread64.c               | 30 +++--------------
 sysdeps/unix/sysv/linux/wordsize-64/pread64.c      |  1 -
 sysdeps/unix/sysv/linux/wordsize-64/syscalls.list  |  1 -
 17 files changed, 64 insertions(+), 370 deletions(-)
 delete mode 100644 sysdeps/unix/sysv/linux/arm/pread.c
 delete mode 100644 sysdeps/unix/sysv/linux/arm/pread64.c
 delete mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/pread.c
 delete mode 100644 sysdeps/unix/sysv/linux/generic/wordsize-32/pread64.c
 delete mode 100644 sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c
 delete mode 100644 sysdeps/unix/sysv/linux/powerpc/powerpc32/pread64.c
 delete mode 100644 sysdeps/unix/sysv/linux/wordsize-64/pread64.c

Comments

Joseph Myers Feb. 23, 2016, 5:57 p.m. UTC | #1
On Tue, 23 Feb 2016, Adhemerval Zanella wrote:

> +/* The n32 have sizeof(off_t) != sizeof(off64_t) so we can't strong/weak
> +   alias the pread to pread64.  We undefine the __ASSUME_WORDSIZE64_ILP32
> +   so two implementation are built.  */
> +#if _MIPS_SIM == _ABIN32
> +# undef __ASSUME_WORDSIZE64_ILP32
>  #endif

I don't see how this will work, since you still need 64-bit arguments 
passed in a single register, and __ASSUME_WORDSIZE64_ILP32 controls 
SYSCALL_LL* in your patch.

Also, you're including sysdeps/unix/sysv/linux/generic/sysdep.h for 
architectures that don't use the generic ABI.  If that's safe, that 
suggests it should just be merged into sysdeps/unix/sysv/linux/sysdep.h 
(in a separate patch with a careful argument for why the merge is safe) 
rather than keeping the headers separate.

The n32 ABI is that 32-bit arguments must be sign-extended to 64-bit when 
passed in registers (even if the arguments are of an unsigned type).  So I 
think it should be safe for pread to be aliased to pread64 for n32 (it 
does have to be that way round, the function being defined with the 64-bit 
argument type) - though aliasing functions with incompatible C types may 
be tricky.
Adhemerval Zanella Netto Feb. 23, 2016, 6:42 p.m. UTC | #2
On 23-02-2016 14:57, Joseph Myers wrote:
> On Tue, 23 Feb 2016, Adhemerval Zanella wrote:
> 
>> +/* The n32 have sizeof(off_t) != sizeof(off64_t) so we can't strong/weak
>> +   alias the pread to pread64.  We undefine the __ASSUME_WORDSIZE64_ILP32
>> +   so two implementation are built.  */
>> +#if _MIPS_SIM == _ABIN32
>> +# undef __ASSUME_WORDSIZE64_ILP32
>>  #endif
> 
> I don't see how this will work, since you still need 64-bit arguments 
> passed in a single register, and __ASSUME_WORDSIZE64_ILP32 controls 
> SYSCALL_LL* in your patch.

It will since mips p{read,write}.c implementation first include sysdep-cancel.h
and by that it will get the correct SYSCALL_LL{64} definition for the ABI.
The undefine and later include on generic p{read,write} will just block the
build symbol and create the alias for p{read,write}64.


> 
> Also, you're including sysdeps/unix/sysv/linux/generic/sysdep.h for 
> architectures that don't use the generic ABI.  If that's safe, that 
> suggests it should just be merged into sysdeps/unix/sysv/linux/sysdep.h 
> (in a separate patch with a careful argument for why the merge is safe) 
> rather than keeping the headers separate.

I decided to add it on generic sysdep.h because it is where port will get
the definition of __ALIGNMENT_ARG.  However I can split the second path
in two, one to include generic sysdep.h and another to define SYSCALL_LL{64}.


> 
> The n32 ABI is that 32-bit arguments must be sign-extended to 64-bit when 
> passed in registers (even if the arguments are of an unsigned type).  So I 
> think it should be safe for pread to be aliased to pread64 for n32 (it 
> does have to be that way round, the function being defined with the 64-bit 
> argument type) - though aliasing functions with incompatible C types may 
> be tricky.

The patch is doing what current implementation for pread{64}.c does for mips.
This alias could be a following cleanup patch (which is not the intention
of this patch).
Mike Frysinger Feb. 24, 2016, 9:41 p.m. UTC | #3
On 23 Feb 2016 15:42, Adhemerval Zanella wrote:
> On 23-02-2016 14:57, Joseph Myers wrote:
> > Also, you're including sysdeps/unix/sysv/linux/generic/sysdep.h for 
> > architectures that don't use the generic ABI.  If that's safe, that 
> > suggests it should just be merged into sysdeps/unix/sysv/linux/sysdep.h 
> > (in a separate patch with a careful argument for why the merge is safe) 
> > rather than keeping the headers separate.
> 
> I decided to add it on generic sysdep.h because it is where port will get
> the definition of __ALIGNMENT_ARG.  However I can split the second path
> in two, one to include generic sysdep.h and another to define SYSCALL_LL{64}.

i don't think splitting the path addresses the contention.  Joseph's
point (which i agree with) is that linux/generic/ is for the "generic
ABI" which the kernel is trying to push for new arches.  if you have
stuff which works across all linux ABI's, then instead of being in
linux/generic/xxx, it should be in linux/xxx.

if that means some things get hoisted out of linux/generic/xxx and
into linux/xxx, then that's OK.
-mike
Adhemerval Zanella Netto Feb. 24, 2016, 10:12 p.m. UTC | #4
On 24-02-2016 18:41, Mike Frysinger wrote:
> On 23 Feb 2016 15:42, Adhemerval Zanella wrote:
>> On 23-02-2016 14:57, Joseph Myers wrote:
>>> Also, you're including sysdeps/unix/sysv/linux/generic/sysdep.h for 
>>> architectures that don't use the generic ABI.  If that's safe, that 
>>> suggests it should just be merged into sysdeps/unix/sysv/linux/sysdep.h 
>>> (in a separate patch with a careful argument for why the merge is safe) 
>>> rather than keeping the headers separate.
>>
>> I decided to add it on generic sysdep.h because it is where port will get
>> the definition of __ALIGNMENT_ARG.  However I can split the second path
>> in two, one to include generic sysdep.h and another to define SYSCALL_LL{64}.
> 
> i don't think splitting the path addresses the contention.  Joseph's
> point (which i agree with) is that linux/generic/ is for the "generic
> ABI" which the kernel is trying to push for new arches.  if you have
> stuff which works across all linux ABI's, then instead of being in
> linux/generic/xxx, it should be in linux/xxx.
> 
> if that means some things get hoisted out of linux/generic/xxx and
> into linux/xxx, then that's OK.
> -mike
> 

I think then best approach would be move __ALIGNMENT_{ARG,COUNT} from generic
to linux/xxx and add the new SYSCALL_LL on linux/xxx as well.  What you think?
Mike Frysinger Feb. 24, 2016, 10:25 p.m. UTC | #5
On 24 Feb 2016 19:12, Adhemerval Zanella wrote:
> On 24-02-2016 18:41, Mike Frysinger wrote:
> > On 23 Feb 2016 15:42, Adhemerval Zanella wrote:
> >> On 23-02-2016 14:57, Joseph Myers wrote:
> >>> Also, you're including sysdeps/unix/sysv/linux/generic/sysdep.h for 
> >>> architectures that don't use the generic ABI.  If that's safe, that 
> >>> suggests it should just be merged into sysdeps/unix/sysv/linux/sysdep.h 
> >>> (in a separate patch with a careful argument for why the merge is safe) 
> >>> rather than keeping the headers separate.
> >>
> >> I decided to add it on generic sysdep.h because it is where port will get
> >> the definition of __ALIGNMENT_ARG.  However I can split the second path
> >> in two, one to include generic sysdep.h and another to define SYSCALL_LL{64}.
> > 
> > i don't think splitting the path addresses the contention.  Joseph's
> > point (which i agree with) is that linux/generic/ is for the "generic
> > ABI" which the kernel is trying to push for new arches.  if you have
> > stuff which works across all linux ABI's, then instead of being in
> > linux/generic/xxx, it should be in linux/xxx.
> > 
> > if that means some things get hoisted out of linux/generic/xxx and
> > into linux/xxx, then that's OK.
> 
> I think then best approach would be move __ALIGNMENT_{ARG,COUNT} from generic
> to linux/xxx and add the new SYSCALL_LL on linux/xxx as well.  What you think?

sgtm.  seems like many of the users in linux/generic/wordsize-32/ could
also be merged back if you're feeling proactive :).
-mike
Adhemerval Zanella Netto Feb. 24, 2016, 10:29 p.m. UTC | #6
On 24-02-2016 19:25, Mike Frysinger wrote:
> On 24 Feb 2016 19:12, Adhemerval Zanella wrote:
>> On 24-02-2016 18:41, Mike Frysinger wrote:
>>> On 23 Feb 2016 15:42, Adhemerval Zanella wrote:
>>>> On 23-02-2016 14:57, Joseph Myers wrote:
>>>>> Also, you're including sysdeps/unix/sysv/linux/generic/sysdep.h for 
>>>>> architectures that don't use the generic ABI.  If that's safe, that 
>>>>> suggests it should just be merged into sysdeps/unix/sysv/linux/sysdep.h 
>>>>> (in a separate patch with a careful argument for why the merge is safe) 
>>>>> rather than keeping the headers separate.
>>>>
>>>> I decided to add it on generic sysdep.h because it is where port will get
>>>> the definition of __ALIGNMENT_ARG.  However I can split the second path
>>>> in two, one to include generic sysdep.h and another to define SYSCALL_LL{64}.
>>>
>>> i don't think splitting the path addresses the contention.  Joseph's
>>> point (which i agree with) is that linux/generic/ is for the "generic
>>> ABI" which the kernel is trying to push for new arches.  if you have
>>> stuff which works across all linux ABI's, then instead of being in
>>> linux/generic/xxx, it should be in linux/xxx.
>>>
>>> if that means some things get hoisted out of linux/generic/xxx and
>>> into linux/xxx, then that's OK.
>>
>> I think then best approach would be move __ALIGNMENT_{ARG,COUNT} from generic
>> to linux/xxx and add the new SYSCALL_LL on linux/xxx as well.  What you think?
> 
> sgtm.  seems like many of the users in linux/generic/wordsize-32/ could
> also be merged back if you're feeling proactive :).
> -mike
> 

Yeap, this is in my plan.
Chris Metcalf Feb. 24, 2016, 11:20 p.m. UTC | #7
On 2/24/2016 5:25 PM, Mike Frysinger wrote:
> On 24 Feb 2016 19:12, Adhemerval Zanella wrote:
>> On 24-02-2016 18:41, Mike Frysinger wrote:
>>> On 23 Feb 2016 15:42, Adhemerval Zanella wrote:
>>>> On 23-02-2016 14:57, Joseph Myers wrote:
>>>>> Also, you're including sysdeps/unix/sysv/linux/generic/sysdep.h for
>>>>> architectures that don't use the generic ABI.  If that's safe, that
>>>>> suggests it should just be merged into sysdeps/unix/sysv/linux/sysdep.h
>>>>> (in a separate patch with a careful argument for why the merge is safe)
>>>>> rather than keeping the headers separate.
>>>> I decided to add it on generic sysdep.h because it is where port will get
>>>> the definition of __ALIGNMENT_ARG.  However I can split the second path
>>>> in two, one to include generic sysdep.h and another to define SYSCALL_LL{64}.
>>> i don't think splitting the path addresses the contention.  Joseph's
>>> point (which i agree with) is that linux/generic/ is for the "generic
>>> ABI" which the kernel is trying to push for new arches.  if you have
>>> stuff which works across all linux ABI's, then instead of being in
>>> linux/generic/xxx, it should be in linux/xxx.
>>>
>>> if that means some things get hoisted out of linux/generic/xxx and
>>> into linux/xxx, then that's OK.
>> I think then best approach would be move __ALIGNMENT_{ARG,COUNT} from generic
>> to linux/xxx and add the new SYSCALL_LL on linux/xxx as well.  What you think?
> sgtm.  seems like many of the users in linux/generic/wordsize-32/ could
> also be merged back if you're feeling proactive :).
> -mike

Agreed, sounds like the right direction.
diff mbox

Patch

diff --git a/sysdeps/unix/sysv/linux/arm/pread.c b/sysdeps/unix/sysv/linux/arm/pread.c
deleted file mode 100644
index 8c9b878..0000000
--- a/sysdeps/unix/sysv/linux/arm/pread.c
+++ /dev/null
@@ -1,36 +0,0 @@ 
-/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
-
-   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 <errno.h>
-#include <endian.h>
-#include <unistd.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-ssize_t
-__libc_pread (int fd, void *buf, size_t count, off_t offset)
-{
-  /* In the ARM EABI, 64-bit values are aligned to even/odd register
-     pairs for syscalls.  */
-  return SYSCALL_CANCEL (pread64, fd, buf, count, 0,
-			 __LONG_LONG_PAIR (offset >> 31, offset));
-}
-
-strong_alias (__libc_pread, __pread)
-weak_alias (__libc_pread, pread)
diff --git a/sysdeps/unix/sysv/linux/arm/pread64.c b/sysdeps/unix/sysv/linux/arm/pread64.c
deleted file mode 100644
index 3364b6a..0000000
--- a/sysdeps/unix/sysv/linux/arm/pread64.c
+++ /dev/null
@@ -1,37 +0,0 @@ 
-/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
-
-   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 <errno.h>
-#include <endian.h>
-#include <unistd.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-ssize_t
-__libc_pread64 (int fd, void *buf, size_t count, off64_t offset)
-{
-  /* In the ARM EABI, 64-bit values are aligned to even/odd register
-     pairs for syscalls.  */
-  return SYSCALL_CANCEL (pread64, fd, buf, count, 0,
-			 __LONG_LONG_PAIR ((off_t) (offset >> 32),
-					   (off_t) (offset & 0xffffffff)));
-}
-
-weak_alias (__libc_pread64, __pread64)
-weak_alias (__libc_pread64, pread64)
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/pread.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/pread.c
deleted file mode 100644
index 0dff648..0000000
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/pread.c
+++ /dev/null
@@ -1,37 +0,0 @@ 
-/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
-   Based on work contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
-
-   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 <assert.h>
-#include <errno.h>
-#include <endian.h>
-#include <unistd.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-ssize_t
-__libc_pread (int fd, void *buf, size_t count, off_t offset)
-{
-  assert (sizeof (offset) == 4);
-  return SYSCALL_CANCEL (pread64, fd,
-                         buf, count, __ALIGNMENT_ARG
-                         __LONG_LONG_PAIR (offset >> 31, offset));
-}
-strong_alias (__libc_pread, __pread)
-weak_alias (__libc_pread, pread)
diff --git a/sysdeps/unix/sysv/linux/generic/wordsize-32/pread64.c b/sysdeps/unix/sysv/linux/generic/wordsize-32/pread64.c
deleted file mode 100644
index 8931900..0000000
--- a/sysdeps/unix/sysv/linux/generic/wordsize-32/pread64.c
+++ /dev/null
@@ -1,34 +0,0 @@ 
-/* Copyright (C) 2011-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Chris Metcalf <cmetcalf@tilera.com>, 2011.
-   Based on work contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
-
-   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 <errno.h>
-#include <endian.h>
-#include <unistd.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-ssize_t
-__libc_pread64 (int fd, void *buf, size_t count, off64_t offset)
-{
-  return SYSCALL_CANCEL (pread64, fd, buf, count, __ALIGNMENT_ARG
-                         __LONG_LONG_PAIR ((off_t) (offset >> 32),
-                                           (off_t) (offset & 0xffffffff)));
-}
-weak_alias (__libc_pread64, __pread64) weak_alias (__libc_pread64, pread64)
diff --git a/sysdeps/unix/sysv/linux/mips/pread.c b/sysdeps/unix/sysv/linux/mips/pread.c
index 02755cb..3092f0b 100644
--- a/sysdeps/unix/sysv/linux/mips/pread.c
+++ b/sysdeps/unix/sysv/linux/mips/pread.c
@@ -16,39 +16,13 @@ 
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <assert.h>
-#include <errno.h>
-#ifndef NO_SGIDEFS_H
-#include <sgidefs.h>
-#endif
-#include <unistd.h>
-#include <endian.h>
-
 #include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-#ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
-#endif
-
-
-ssize_t
-__libc_pread (int fd, void *buf, size_t count, off_t offset)
-{
-#if _MIPS_SIM != _ABI64
-  assert (sizeof (offset) == 4);
-#endif
 
-#if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64
-  return SYSCALL_CANCEL (pread, fd, buf, count, offset);
-#else
-  return SYSCALL_CANCEL (pread, fd, buf, count, 0,
-			 __LONG_LONG_PAIR (offset >> 31, offset));
+/* The n32 have sizeof(off_t) != sizeof(off64_t) so we can't strong/weak
+   alias the pread to pread64.  We undefine the __ASSUME_WORDSIZE64_ILP32
+   so two implementation are built.  */
+#if _MIPS_SIM == _ABIN32
+# undef __ASSUME_WORDSIZE64_ILP32
 #endif
-}
 
-strong_alias (__libc_pread, __pread)
-weak_alias (__libc_pread, pread)
+#include <sysdeps/unix/sysv/linux/pread.c>
diff --git a/sysdeps/unix/sysv/linux/mips/pread64.c b/sysdeps/unix/sysv/linux/mips/pread64.c
index ed0e91c..cd3b5fd 100644
--- a/sysdeps/unix/sysv/linux/mips/pread64.c
+++ b/sysdeps/unix/sysv/linux/mips/pread64.c
@@ -16,35 +16,13 @@ 
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#ifndef NO_SGIDEFS_H
-#include <sgidefs.h>
-#endif
-#include <unistd.h>
-#include <endian.h>
-
 #include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-#ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
-#endif
-
 
-ssize_t
-__libc_pread64 (int fd, void *buf, size_t count, off64_t offset)
-{
-#if _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64
-  return SYSCALL_CANCEL (pread, fd, buf, count, offset);
-#else
-  return SYSCALL_CANCEL (pread, fd, buf, count, 0,
-			 __LONG_LONG_PAIR ((off_t) (offset >> 32),
-					   (off_t) (offset & 0xffffffff)));
+/* The n32 have sizeof(off_t) != sizeof(off64_t) so we can't strong/weak
+   alias the pread to pread64.  We undefine the __ASSUME_WORDSIZE64_ILP32
+   so two implementation are built.  */
+#if _MIPS_SIM == _ABIN32
+# undef __ASSUME_WORDSIZE64_ILP32
 #endif
-}
 
-weak_alias (__libc_pread64, __pread64)
-weak_alias (__libc_pread64, pread64)
+#include <sysdeps/unix/sysv/linux/pread64.c>
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c b/sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c
deleted file mode 100644
index 2d67013..0000000
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/pread.c
+++ /dev/null
@@ -1,34 +0,0 @@ 
-/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
-
-   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 <assert.h>
-#include <errno.h>
-#include <unistd.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-ssize_t
-__libc_pread (int fd, void *buf, size_t count, off_t offset)
-{
-  /* On PPC32 64bit values are aligned in odd/even register pairs.  */
-  return SYSCALL_CANCEL (pread, fd, buf, count, 0, offset >> 31, offset);
-}
-
-strong_alias (__libc_pread, __pread)
-weak_alias (__libc_pread, pread)
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/pread64.c b/sysdeps/unix/sysv/linux/powerpc/powerpc32/pread64.c
deleted file mode 100644
index 712ab72..0000000
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/pread64.c
+++ /dev/null
@@ -1,35 +0,0 @@ 
-/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
-
-   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 <errno.h>
-#include <unistd.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-
-ssize_t
-__libc_pread64 (int fd, void *buf, size_t count, off64_t offset)
-{
-  /* On PPC32 64bit values are aligned in odd/even register pairs.  */
-  return SYSCALL_CANCEL (pread, fd, buf, count, 0, (long) (offset >> 32),
-			 (long) offset);
-}
-
-weak_alias (__libc_pread64, __pread64)
-weak_alias (__libc_pread64, pread64)
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
index 390ce24..c12fd7f 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/sysdep.h
@@ -27,13 +27,6 @@ 
    Handle them here so they can be catched by both C and assembler stubs in
    glibc.  */
 
-#ifdef __NR_pread64
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
-#endif
-
 #ifdef __NR_pwrite64
 # ifdef __NR_pwrite
 #  error "__NR_pwrite and __NR_pwrite64 both defined???"
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
index 761f3ea..c39a0f2 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/sysdep.h
@@ -34,13 +34,6 @@ 
    Handle them here so they can be catched by both C and assembler stubs in
    glibc.  */
 
-#ifdef __NR_pread64
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
-#endif
-
 #ifdef __NR_pwrite64
 # ifdef __NR_pwrite
 #  error "__NR_pwrite and __NR_pwrite64 both defined???"
diff --git a/sysdeps/unix/sysv/linux/pread.c b/sysdeps/unix/sysv/linux/pread.c
index 4aa3c67..a088423 100644
--- a/sysdeps/unix/sysv/linux/pread.c
+++ b/sysdeps/unix/sysv/linux/pread.c
@@ -16,33 +16,22 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <assert.h>
-#include <errno.h>
-#include <endian.h>
 #include <unistd.h>
-
 #include <sysdep-cancel.h>
-#include <sys/syscall.h>
 
-#ifdef __NR_pread64		/* Newer kernels renamed but it's the same.  */
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
-#endif
+#if __WORDSIZE != 64 && !defined(__ASSUME_WORDSIZE64_ILP32)
 
+# ifndef __NR_pread
+#  define __NR_pread __NR_pread64
+# endif
 
 ssize_t
 __libc_pread (int fd, void *buf, size_t count, off_t offset)
 {
-  ssize_t result;
-
-  assert (sizeof (offset) == 4);
-  result = SYSCALL_CANCEL (pread, fd, buf, count,
-			   __LONG_LONG_PAIR (offset >> 31, offset));
-
-  return result;
+  return SYSCALL_CANCEL (pread, fd, buf, count,
+			 __ALIGNMENT_ARG SYSCALL_LL (offset));
 }
 
 strong_alias (__libc_pread, __pread)
 weak_alias (__libc_pread, pread)
+#endif
diff --git a/sysdeps/unix/sysv/linux/pread64.c b/sysdeps/unix/sysv/linux/pread64.c
index 7b5019a..56a1de0 100644
--- a/sysdeps/unix/sysv/linux/pread64.c
+++ b/sysdeps/unix/sysv/linux/pread64.c
@@ -16,28 +16,25 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <endian.h>
 #include <unistd.h>
-
 #include <sysdep-cancel.h>
-#include <sys/syscall.h>
 
-#ifdef __NR_pread64		/* Newer kernels renamed but it's the same.  */
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
+#ifndef __NR_pread64
+# define __NR_pread64 __NR_pread
 #endif
 
-
 ssize_t
 __libc_pread64 (int fd, void *buf, size_t count, off64_t offset)
 {
-  return SYSCALL_CANCEL (pread, fd, buf, count,
-			 __LONG_LONG_PAIR ((off_t) (offset >> 32),
-					   (off_t) (offset & 0xffffffff)));
+  return SYSCALL_CANCEL (pread64, fd, buf, count,
+			 __ALIGNMENT_ARG SYSCALL_LL64 (offset));
 }
 
 weak_alias (__libc_pread64, __pread64)
 weak_alias (__libc_pread64, pread64)
+
+#if __WORDSIZE == 64 || defined __ASSUME_WORDSIZE64_ILP32
+strong_alias (__libc_pread64, __libc_pread)
+weak_alias (__libc_pread64, __pread)
+weak_alias (__libc_pread64, pread)
+#endif
diff --git a/sysdeps/unix/sysv/linux/sh/pread.c b/sysdeps/unix/sysv/linux/sh/pread.c
index 8afada5..d3f99f3 100644
--- a/sysdeps/unix/sysv/linux/sh/pread.c
+++ b/sysdeps/unix/sysv/linux/sh/pread.c
@@ -16,28 +16,8 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <assert.h>
-#include <errno.h>
-#include <unistd.h>
-#include <endian.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-#ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
-#endif
-
-
-ssize_t
-__libc_pread (int fd, void *buf, size_t count, off_t offset)
-{
-  return SYSCALL_CANCEL (pread, fd, buf, count, 0,
-			 __LONG_LONG_PAIR (offset >> 31, offset));
-}
-
-strong_alias (__libc_pread, __pread)
-weak_alias (__libc_pread, pread)
+/* SH4 ABI does not really require argument alignment for 64-bits, but
+   the kernel interface for pread adds a dummy long argument before the
+   offset.  */
+#define __ALIGNMENT_ARG
+#include <sysdeps/unix/sysv/linux/pread.c>
diff --git a/sysdeps/unix/sysv/linux/sh/pread64.c b/sysdeps/unix/sysv/linux/sh/pread64.c
index cfc751d..b2e8a25 100644
--- a/sysdeps/unix/sysv/linux/sh/pread64.c
+++ b/sysdeps/unix/sysv/linux/sh/pread64.c
@@ -16,28 +16,8 @@ 
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#include <errno.h>
-#include <unistd.h>
-#include <endian.h>
-
-#include <sysdep-cancel.h>
-#include <sys/syscall.h>
-
-#ifdef __NR_pread64             /* Newer kernels renamed but it's the same.  */
-# ifdef __NR_pread
-#  error "__NR_pread and __NR_pread64 both defined???"
-# endif
-# define __NR_pread __NR_pread64
-#endif
-
-
-ssize_t
-__libc_pread64 (int fd, void *buf, size_t count, off64_t offset)
-{
-  return SYSCALL_CANCEL (pread, fd, buf, count, 0,
-			 __LONG_LONG_PAIR ((off_t) (offset >> 32),
-					   (off_t) (offset & 0xffffffff)));
-}
-
-weak_alias (__libc_pread64, __pread64)
-weak_alias (__libc_pread64, pread64)
+/* SH4 ABI does not really require argument alignment for 64-bits, but
+   the kernel interface for pread adds a dummy long argument before the
+   offset.  */
+#define __ALIGNMENT_ARG
+#include <sysdeps/unix/sysv/linux/pread64.c>
diff --git a/sysdeps/unix/sysv/linux/wordsize-64/pread64.c b/sysdeps/unix/sysv/linux/wordsize-64/pread64.c
deleted file mode 100644
index b7f298d..0000000
--- a/sysdeps/unix/sysv/linux/wordsize-64/pread64.c
+++ /dev/null
@@ -1 +0,0 @@ 
-/* Empty since the pread syscall is equivalent.  */
diff --git a/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list b/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
index 19cc6d9..7d5f6a5 100644
--- a/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
+++ b/sysdeps/unix/sysv/linux/wordsize-64/syscalls.list
@@ -3,7 +3,6 @@ 
 # Whee! 64-bit systems naturally implement llseek.
 llseek		EXTRA	lseek		i:iii	__libc_lseek	__lseek lseek __libc_lseek64 __llseek llseek __lseek64 lseek64
 lseek		llseek	-
-pread		-	pread		Ci:ibni	__libc_pread	__libc_pread64 __pread pread __pread64 pread64
 pwrite		-	pwrite		Ci:ibni	__libc_pwrite	__libc_pwrite64 __pwrite pwrite __pwrite64 pwrite64
 fstatfs		-	fstatfs		i:ip	__fstatfs	fstatfs fstatfs64 __fstatfs64
 statfs		-	statfs		i:sp	__statfs	statfs statfs64