diff --git a/nptl/Makefile b/nptl/Makefile
index f7e3766e3c..240f35802f 100644
--- a/nptl/Makefile
+++ b/nptl/Makefile
@@ -23,7 +23,7 @@ subdir	:= nptl
 include ../Makeconfig
 
 headers := pthread.h semaphore.h bits/semaphore.h threads.h \
-	   bits/mutex-internal.h
+	   bits/mutex-internal.h bits/rwlock-internal.h
 
 extra-libs := libpthread
 extra-libs-others := $(extra-libs)
diff --git a/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h b/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
index 78abd6960b..33c7928bf2 100644
--- a/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/aarch64/nptl/bits/pthreadtypes-arch.h
@@ -44,19 +44,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  unsigned int __flags;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/aarch64/nptl/bits/rwlock-internal.h b/sysdeps/aarch64/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..c5ea2b2469
--- /dev/null
+++ b/sysdeps/aarch64/nptl/bits/rwlock-internal.h
@@ -0,0 +1,41 @@
+/* AArch64 internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+  int __cur_writer;
+  int __shared;
+  unsigned long int __pad1;
+  unsigned long int __pad2;
+  unsigned int __flags;
+};
+
+#define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags
+
+#endif
diff --git a/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h b/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
index b832590d82..09692ab4aa 100644
--- a/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/alpha/nptl/bits/pthreadtypes-arch.h
@@ -32,21 +32,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned int __flags;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/alpha/nptl/bits/rwlock-internal.h b/sysdeps/alpha/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..32e18a4a4e
--- /dev/null
+++ b/sysdeps/alpha/nptl/bits/rwlock-internal.h
@@ -0,0 +1,43 @@
+/* Alpha internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+  int __cur_writer;
+  int __shared;
+  unsigned long int __pad1;
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+};
+
+#define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags
+
+#endif
diff --git a/sysdeps/arm/nptl/bits/pthreadtypes-arch.h b/sysdeps/arm/nptl/bits/pthreadtypes-arch.h
index 5ae7d0d721..339956cfa2 100644
--- a/sysdeps/arm/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/arm/nptl/bits/pthreadtypes-arch.h
@@ -33,30 +33,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if __BYTE_ORDER == __BIG_ENDIAN
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-#else
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  unsigned char __shared;
-  unsigned char __pad1;
-  unsigned char __pad2;
-#endif
-  int __cur_writer;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/csky/nptl/bits/pthreadtypes-arch.h b/sysdeps/csky/nptl/bits/pthreadtypes-arch.h
index 685515724f..4bcc8d7d5b 100644
--- a/sysdeps/csky/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/csky/nptl/bits/pthreadtypes-arch.h
@@ -34,28 +34,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-/* Paddings in this structure are not strictly necessary on C-SKY.
-   They are left for extensibility as most other architecture do so.  */
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if __BYTE_ORDER == __BIG_ENDIAN
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  unsigned char __flags;
-#else
-  unsigned char __flags;
-  unsigned char __shared;
-  unsigned char __pad1;
-  unsigned char __pad2;
-#endif
-  int __cur_writer;
-};
-
-#endif
+#endif /* bits/pthreadtypes.h */
diff --git a/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h b/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
index c11add1af8..58e077cb4e 100644
--- a/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
@@ -43,36 +43,4 @@
 #define __LOCK_ALIGNMENT __attribute__ ((__aligned__(16)))
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  /* In the old Linuxthreads pthread_rwlock_t, this is the
-     start of the 4-word 16-byte aligned lock structure. The
-     next four words are all set to 1 by the Linuxthreads
-     PTHREAD_RWLOCK_INITIALIZER. We ignore them in NPTL.  */
-  int __compat_padding[4] __attribute__ ((__aligned__(16)));
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-  int __cur_writer;
-  /* An unused word, reserved for future use. It was added
-     to maintain the location of the flags from the Linuxthreads
-     layout of this structure.  */
-  int __reserved1;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __pad2;
-  unsigned char __pad1;
-  unsigned char __shared;
-  unsigned char __flags;
-  /* The NPTL pthread_rwlock_t is 4 words smaller than the
-     Linuxthreads version. One word is in the middle of the
-     structure, the other three are at the end.  */
-  int __reserved2;
-  int __reserved3;
-  int __reserved4;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/hppa/nptl/bits/rwlock-internal.h b/sysdeps/hppa/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..5370c7c3bb
--- /dev/null
+++ b/sysdeps/hppa/nptl/bits/rwlock-internal.h
@@ -0,0 +1,58 @@
+/* HPPA  internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  /* In the old Linuxthreads pthread_rwlock_t, this is the
+     start of the 4-word 16-byte aligned lock structure. The
+     next four words are all set to 1 by the Linuxthreads
+     PTHREAD_RWLOCK_INITIALIZER. We ignore them in NPTL.  */
+  int __compat_padding[4] __attribute__ ((__aligned__(16)));
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+  int __cur_writer;
+  /* An unused word, reserved for future use. It was added
+     to maintain the location of the flags from the Linuxthreads
+     layout of this structure.  */
+  int __reserved1;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __pad2;
+  unsigned char __pad1;
+  unsigned char __shared;
+  unsigned char __flags;
+  /* The NPTL pthread_rwlock_t is 4 words smaller than the
+     Linuxthreads version. One word is in the middle of the
+     structure, the other three are at the end.  */
+  int __reserved2;
+  int __reserved3;
+  int __reserved4;
+};
+
+#define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  { 0, 0, 0, 0 }, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags, 0, 0, 0
+
+#endif
diff --git a/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h b/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
index 7a1fd3ed28..e3b8175ea0 100644
--- a/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/ia64/nptl/bits/pthreadtypes-arch.h
@@ -32,23 +32,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-/* Data structure for reader-write lock variable handling.  The
-   structure of the attribute type is not exposed on purpose.  */
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned int __flags;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/ia64/nptl/bits/rwlock-internal.h b/sysdeps/ia64/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..de991c8dd4
--- /dev/null
+++ b/sysdeps/ia64/nptl/bits/rwlock-internal.h
@@ -0,0 +1,43 @@
+/* IA64 internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+  int __cur_writer;
+  int __shared;
+  unsigned long int __pad1;
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+};
+
+#define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags
+
+#endif
diff --git a/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h b/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
index 0647c48b5a..fe3ac611f8 100644
--- a/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/m68k/nptl/bits/pthreadtypes-arch.h
@@ -34,21 +34,4 @@
 #define __LOCK_ALIGNMENT __attribute__ ((__aligned__ (4)))
 #define __ONCE_ALIGNMENT __attribute__ ((__aligned__ (4)))
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers  __attribute__ ((__aligned__ (4)));
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  int __cur_writer;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h b/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
index 21b090aaf6..ed2852a018 100644
--- a/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/microblaze/nptl/bits/pthreadtypes-arch.h
@@ -34,30 +34,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#  if __BYTE_ORDER == __BIG_ENDIAN
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-#  else
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  unsigned char __shared;
-  unsigned char __pad1;
-  unsigned char __pad2;
-#  endif
-  int __cur_writer;
-};
-
 #endif	/* bits/pthreadtypes.h.  */
diff --git a/sysdeps/mips/nptl/bits/pthreadtypes-arch.h b/sysdeps/mips/nptl/bits/pthreadtypes-arch.h
index 5bcc90a7fe..f0f9133df4 100644
--- a/sysdeps/mips/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/mips/nptl/bits/pthreadtypes-arch.h
@@ -41,40 +41,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if _MIPS_SIM == _ABI64
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned int __flags;
-# else
-# if __BYTE_ORDER == __BIG_ENDIAN
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-# else
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  unsigned char __shared;
-  unsigned char __pad1;
-  unsigned char __pad2;
-# endif
-  int __cur_writer;
-#endif
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/mips/nptl/bits/rwlock-internal.h b/sysdeps/mips/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..93bf7cd442
--- /dev/null
+++ b/sysdeps/mips/nptl/bits/rwlock-internal.h
@@ -0,0 +1,71 @@
+/* MIPS internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+#if _MIPS_SIM == _ABI64
+  int __cur_writer;
+  int __shared;
+  unsigned long int __pad1;
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+# else
+# if __BYTE_ORDER == __BIG_ENDIAN
+  unsigned char __pad1;
+  unsigned char __pad2;
+  unsigned char __shared;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+# else
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+  unsigned char __shared;
+  unsigned char __pad1;
+  unsigned char __pad2;
+# endif
+  int __cur_writer;
+#endif
+};
+
+#if _MIPS_SIM == _ABI64
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags
+#else
+# if __BYTE_ORDER == __BIG_ENDIAN
+#  define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, __flags, 0
+# else
+#  define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, __flags, 0, 0, 0, 0
+# endif
+#endif
+
+#endif
diff --git a/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h b/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
index 7e71f723d0..28d1d84ad8 100644
--- a/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/nios2/nptl/bits/pthreadtypes-arch.h
@@ -34,30 +34,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if __BYTE_ORDER == __BIG_ENDIAN
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-#else
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  unsigned char __shared;
-  unsigned char __pad1;
-  unsigned char __pad2;
-#endif
-  int __cur_writer;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/nptl/bits/rwlock-internal.h b/sysdeps/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..98ec18db47
--- /dev/null
+++ b/sysdeps/nptl/bits/rwlock-internal.h
@@ -0,0 +1,62 @@
+/* Default internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef __RWLOCK_INTERNAL_H
+#define __RWLOCK_INTERNAL_H
+
+#include <bits/endian.h>
+
+/* Generic struct for both POSIX read-write lock.  New ports are expected
+   to use the default layout, however archictetures can redefine it to add
+   arch-specific extensions (such as lock-elision).  The struct have a size
+   of 32 bytes on both LP32 and LP64 architectures.  */
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+  /* FLAGS must stay at its position in the structure to maintain
+     binary compatibility.  */
+#if __BYTE_ORDER == __BIG_ENDIAN
+  unsigned char __pad1;
+  unsigned char __pad2;
+  unsigned char __shared;
+  unsigned char __flags;
+#else
+  unsigned char __flags;
+  unsigned char __shared;
+  unsigned char __pad1;
+  unsigned char __pad2;
+#endif
+  int __cur_writer;
+};
+
+#if __BYTE_ORDER == __BIG_ENDIAN
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, __flags, 0
+#else
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, __flags, 0, 0, 0, 0
+#endif
+
+#endif
diff --git a/sysdeps/nptl/bits/thread-shared-types.h b/sysdeps/nptl/bits/thread-shared-types.h
index 6bfaa79ca1..6e596d4528 100644
--- a/sysdeps/nptl/bits/thread-shared-types.h
+++ b/sysdeps/nptl/bits/thread-shared-types.h
@@ -39,10 +39,7 @@
 
    Same idea but for the once locking primitive:
 
-   __ONCE_ALIGNMENT - for pthread_once_t/once_flag definition.
-
-   And finally the internal pthread_rwlock_t (struct __pthread_rwlock_arch_t)
-   must be defined.  */
+   __ONCE_ALIGNMENT - for pthread_once_t/once_flag definition.  */
 
 #include <bits/pthreadtypes-arch.h>
 
@@ -83,6 +80,19 @@ typedef struct __pthread_internal_slist
 
 #include <bits/mutex-internal.h>
 
+/* Arch-sepecific read-write lock definitions.  A generic implementation is
+   provided by sysdeps/nptl/bits/rwlock-internal.h.  If required, an
+   architecture can override it by defining:
+
+   1. struct __pthread_rwlock_arch_t (used on pthread_rwlock_t definition).
+      It should contain at least the internal members defined in the
+      generic version.
+
+   2. The macro __PTHREAD_RWLOCK_INITIALIZER used for static initialization.
+      It should initialize the rwlock internal type.  */
+
+#include <bits/rwlock-internal.h>
+
 
 /* Common definition of pthread_cond_t. */
 
diff --git a/sysdeps/nptl/pthread.h b/sysdeps/nptl/pthread.h
index e673e3f4fc..a503b09993 100644
--- a/sysdeps/nptl/pthread.h
+++ b/sysdeps/nptl/pthread.h
@@ -105,34 +105,13 @@ enum
   PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP
 };
 
-/* Define __PTHREAD_RWLOCK_INT_FLAGS_SHARED to 1 if pthread_rwlock_t
-   has the shared field.  All 64-bit architectures have the shared field
-   in pthread_rwlock_t.  */
-#ifndef __PTHREAD_RWLOCK_INT_FLAGS_SHARED
-# if __WORDSIZE == 64
-#  define __PTHREAD_RWLOCK_INT_FLAGS_SHARED 1
-# endif
-#endif
 
 /* Read-write lock initializers.  */
 # define PTHREAD_RWLOCK_INITIALIZER \
-  { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }
+  { { __PTHREAD_RWLOCK_INITIALIZER (PTHREAD_RWLOCK_DEFAULT_NP) } }
 # ifdef __USE_GNU
-#  ifdef __PTHREAD_RWLOCK_INT_FLAGS_SHARED
-#   define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
-  { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,					      \
-	PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP } }
-#  else
-#   if __BYTE_ORDER == __LITTLE_ENDIAN
-#    define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
-  { { 0, 0, 0, 0, 0, 0, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP, \
-      0, 0, 0, 0 } }
-#   else
-#    define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
-  { { 0, 0, 0, 0, 0, 0, 0, 0, 0, PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP,\
-      0 } }
-#   endif
-#  endif
+#  define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
+  { { __PTHREAD_RWLOCK_INITIALIZER (PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP) } }
 # endif
 #endif  /* Unix98 or XOpen2K */
 
diff --git a/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h b/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
index 429d42d77d..eff60d6306 100644
--- a/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/powerpc/nptl/bits/pthreadtypes-arch.h
@@ -41,31 +41,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if __WORDSIZE == 64
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned int __flags;
-#else
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  int __cur_writer;
-#endif
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/powerpc/nptl/bits/rwlock-internal.h b/sysdeps/powerpc/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..ee457b0bfa
--- /dev/null
+++ b/sysdeps/powerpc/nptl/bits/rwlock-internal.h
@@ -0,0 +1,61 @@
+/* PowerPC internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+#if __WORDSIZE == 64
+  int __cur_writer;
+  int __shared;
+  unsigned char __rwelision;
+  unsigned char __pad1[7];
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+# define __PTHREAD_RWLOCK_ELISION_EXTRA 0, {0, 0, 0, 0, 0, 0, 0 }
+#else
+  unsigned char __rwelision;
+  unsigned char __pad2;
+  unsigned char __shared;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+  int __cur_writer;
+# define __PTHREAD_RWLOCK_ELISION_EXTRA 0
+#endif
+};
+
+#if __WORDSIZE == 64
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, __PTHREAD_RWLOCK_ELISION_EXTRA, 0, __flags
+#else
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, __PTHREAD_RWLOCK_ELISION_EXTRA, 0, 0, __flags, 0
+#endif
+
+#endif
diff --git a/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h b/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h
index 31f46ecbde..330c302fd2 100644
--- a/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/riscv/nptl/bits/pthreadtypes-arch.h
@@ -38,23 +38,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-/* There is a lot of padding in this structure.  While it's not strictly
-   necessary on RISC-V, we're going to leave it in to be on the safe side in
-   case it's needed in the future.  Most other architectures have the padding,
-   so this gives us the same extensibility as everyone else has.  */
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  unsigned int __flags;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/riscv/nptl/bits/rwlock-internal.h b/sysdeps/riscv/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..65a094eedc
--- /dev/null
+++ b/sysdeps/riscv/nptl/bits/rwlock-internal.h
@@ -0,0 +1,45 @@
+/* RISC-V internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+/* There is a lot of padding in this structure.  While it's not strictly
+   necessary on RISC-V, we're going to leave it in to be on the safe side in
+   case it's needed in the future.  Most other architectures have the padding,
+   so this gives us the same extensibility as everyone else has.  */
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+  int __cur_writer;
+  int __shared;
+  unsigned long int __pad1;
+  unsigned long int __pad2;
+  unsigned int __flags;
+};
+
+#define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags
+
+#endif
diff --git a/sysdeps/s390/nptl/bits/pthreadtypes-arch.h b/sysdeps/s390/nptl/bits/pthreadtypes-arch.h
index 5fd32ba756..99f27d3fd0 100644
--- a/sysdeps/s390/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/s390/nptl/bits/pthreadtypes-arch.h
@@ -40,31 +40,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if __WORDSIZE == 64
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned int __flags;
-# else
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  int __cur_writer;
-#endif
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/s390/nptl/bits/rwlock-internal.h b/sysdeps/s390/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..5adad874a3
--- /dev/null
+++ b/sysdeps/s390/nptl/bits/rwlock-internal.h
@@ -0,0 +1,58 @@
+/* S390 internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+#if __WORDSIZE == 64
+  int __cur_writer;
+  int __shared;
+  unsigned long int __pad1;
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+# else
+  unsigned char __pad1;
+  unsigned char __pad2;
+  unsigned char __shared;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+  int __cur_writer;
+#endif
+};
+
+#if __WORDSIZE == 64
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags
+#else
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, __flags, 0
+#endif
+
+#endif
diff --git a/sysdeps/sh/nptl/bits/pthreadtypes-arch.h b/sysdeps/sh/nptl/bits/pthreadtypes-arch.h
index ec861133ca..dd70a5d4fd 100644
--- a/sysdeps/sh/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/sh/nptl/bits/pthreadtypes-arch.h
@@ -33,30 +33,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if __BYTE_ORDER == __BIG_ENDIAN
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-#else
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  unsigned char __shared;
-  unsigned char __pad1;
-  unsigned char __pad2;
-#endif
-  unsigned long int __cur_writer;
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h b/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
index 4cda2376d2..8ea295d0a0 100644
--- a/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/sparc/nptl/bits/pthreadtypes-arch.h
@@ -42,31 +42,4 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#if __WORDSIZE == 64
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned int __flags;
-#else
-  unsigned char __pad1;
-  unsigned char __pad2;
-  unsigned char __shared;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  int __cur_writer;
-#endif
-};
-
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/sparc/nptl/bits/rwlock-internal.h b/sysdeps/sparc/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..8d3e799f46
--- /dev/null
+++ b/sysdeps/sparc/nptl/bits/rwlock-internal.h
@@ -0,0 +1,58 @@
+/* SPARC internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+#if __WORDSIZE == 64
+  int __cur_writer;
+  int __shared;
+  unsigned long int __pad1;
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+#else
+  unsigned char __pad1;
+  unsigned char __pad2;
+  unsigned char __shared;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+  int __cur_writer;
+#endif
+};
+
+#if __WORDSIZE == 64
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, __flags
+#else
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, 0, __flags, 0
+#endif
+
+#endif
diff --git a/sysdeps/unix/sysv/linux/hppa/pthread.h b/sysdeps/unix/sysv/linux/hppa/pthread.h
index 3d1e7f3a45..61e5426712 100644
--- a/sysdeps/unix/sysv/linux/hppa/pthread.h
+++ b/sysdeps/unix/sysv/linux/hppa/pthread.h
@@ -104,23 +104,13 @@ enum
   PTHREAD_RWLOCK_DEFAULT_NP = PTHREAD_RWLOCK_PREFER_READER_NP
 };
 
-/* Define __PTHREAD_RWLOCK_INT_FLAGS_SHARED to 1 if pthread_rwlock_t
-   has the shared field.  All 64-bit architectures have the shared field
-   in pthread_rwlock_t.  */
-#ifndef __PTHREAD_RWLOCK_INT_FLAGS_SHARED
-# if __WORDSIZE == 64
-#  define __PTHREAD_RWLOCK_INT_FLAGS_SHARED 1
-# endif
-#endif
-
 
 /* Read-write lock initializers.  */
 # define PTHREAD_RWLOCK_INITIALIZER \
-  { { { 0, 0, 0, 0 }, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 } }
+  { { __PTHREAD_RWLOCK_INITIALIZER (PTHREAD_RWLOCK_DEFAULT_NP) } }
 # ifdef __USE_GNU
 #  define PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP \
-   { { { 0, 0, 0, 0 }, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \
-       PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP, 0, 0, 0 } }
+  { { __PTHREAD_RWLOCK_INITIALIZER (PTHREAD_RWLOCK_PREFER_WRITER_NONRECURSIVE_NP) } }
 # endif
 #endif  /* Unix98 or XOpen2K */
 
diff --git a/sysdeps/x86/nptl/bits/pthreadtypes-arch.h b/sysdeps/x86/nptl/bits/pthreadtypes-arch.h
index 668ec4a5d5..426a20751d 100644
--- a/sysdeps/x86/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/x86/nptl/bits/pthreadtypes-arch.h
@@ -50,34 +50,6 @@
 #define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
-struct __pthread_rwlock_arch_t
-{
-  unsigned int __readers;
-  unsigned int __writers;
-  unsigned int __wrphase_futex;
-  unsigned int __writers_futex;
-  unsigned int __pad3;
-  unsigned int __pad4;
-#ifdef __x86_64__
-  int __cur_writer;
-  int __shared;
-  unsigned long int __pad1;
-  unsigned long int __pad2;
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned int __flags;
-# define __PTHREAD_RWLOCK_INT_FLAGS_SHARED	1
-#else
-  /* FLAGS must stay at this position in the structure to maintain
-     binary compatibility.  */
-  unsigned char __flags;
-  unsigned char __shared;
-  unsigned char __pad1;
-  unsigned char __pad2;
-  int __cur_writer;
-#endif
-};
-
 #ifndef __x86_64__
 /* Extra attributes for the cleanup functions.  */
 # define __cleanup_fct_attribute __attribute__ ((__regparm__ (1)))
diff --git a/sysdeps/x86/nptl/bits/rwlock-internal.h b/sysdeps/x86/nptl/bits/rwlock-internal.h
new file mode 100644
index 0000000000..7f4728ec84
--- /dev/null
+++ b/sysdeps/x86/nptl/bits/rwlock-internal.h
@@ -0,0 +1,65 @@
+/* x86 internal rwlock struct definitions.
+   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/>.  */
+
+#ifndef _RWLOCK_INTERNAL_H
+#define _RWLOCK_INTERNAL_H
+
+struct __pthread_rwlock_arch_t
+{
+  unsigned int __readers;
+  unsigned int __writers;
+  unsigned int __wrphase_futex;
+  unsigned int __writers_futex;
+  unsigned int __pad3;
+  unsigned int __pad4;
+#ifdef __x86_64__
+  int __cur_writer;
+  int __shared;
+  signed char __rwelision;
+# ifdef  __ILP32__
+  unsigned char __pad1[3];
+#  define __PTHREAD_RWLOCK_ELISION_EXTRA 0, { 0, 0, 0 }
+# else
+  unsigned char __pad1[7];
+#  define __PTHREAD_RWLOCK_ELISION_EXTRA 0, { 0, 0, 0, 0, 0, 0, 0 }
+# endif
+  unsigned long int __pad2;
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned int __flags;
+#else /* __x86_64__  */
+  /* FLAGS must stay at this position in the structure to maintain
+     binary compatibility.  */
+  unsigned char __flags;
+  unsigned char __shared;
+  signed char __rwelision;
+  unsigned char __pad2;
+  int __cur_writer;
+#endif
+};
+
+#ifdef __x86_64__
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, 0, 0, __PTHREAD_RWLOCK_ELISION_EXTRA, 0, __flags
+#else
+# define __PTHREAD_RWLOCK_INITIALIZER(__flags) \
+  0, 0, 0, 0, 0, 0, __flags, 0, 0, 0, 0
+#endif
+
+#endif
