S390: Refactor strncpy ifunc handling.

The ifunc handling for strncpy is adjusted in order to omit ifunc
variants if those will never be used as the minimum architecture level
already supports newer CPUs by default.
Glibc internal calls will then also use the "newer" ifunc variant.

Note: The fallback s390-32/s390-64 ifunc variants are now moved to
the strncpy-z900.S files. The s390-32/s390-64 files multiarch/strncpy.c
and strncpy.S are deleted.

ChangeLog:

	* sysdeps/s390/multiarch/Makefile
	(sysdep_routines): Remove strncpy variants.
	* sysdeps/s390/Makefile (sysdep_routines): Add strncpy variants.
	* sysdeps/s390/multiarch/ifunc-impl-list.c
	(__libc_ifunc_impl_list): Refactor ifunc handling for strncpy.
	* sysdeps/s390/multiarch/strncpy-vx.S: Move to ...
	* sysdeps/s390/strncpy-vx.S: ... here and adjust ifunc handling.
	* sysdeps/s390/multiarch/strncpy.c: Move to ...
	* sysdeps/s390/strncpy.c: ... here and adjust ifunc handling.
	* sysdeps/s390/ifunc-strncpy.h: New file.
	* sysdeps/s390/s390-64/strncpy.S: Move to ...
	* sysdeps/s390/s390-64/strncpy-z900.S: ... here
	and adjust ifunc handling.
	* sysdeps/s390/s390-32/strncpy.S: Move to ...
	* sysdeps/s390/s390-32/strncpy-z900.S: ... here
	and adjust ifunc handling.
	* sysdeps/s390/s390-32/multiarch/strncpy.c: Delete file.
	* sysdeps/s390/s390-64/multiarch/strncpy.c: Likewise.

2 files changed, 13 insertions, 24 deletions

diff --git a/sysdeps/s390/s390-32/multiarch/strncpy.c b/sysdeps/s390/s390-32/multiarch/strncpy.c
deleted file mode 100644
index 57f9df18d1..0000000000
--- a/sysdeps/s390/s390-32/multiarch/strncpy.c
+++ /dev/null
@@ -1,21 +0,0 @@
-/* Multiple versions of strncpy.
-   Copyright (C) 2015-2018 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/>.  */
-
-/* This wrapper-file is needed, because otherwise file
-   sysdeps/s390/s390-[32|64]/strncpy.S will be used.  */
-#include <sysdeps/s390/multiarch/strncpy.c>
diff --git a/sysdeps/s390/s390-32/strncpy.S b/sysdeps/s390/s390-32/strncpy-z900.S
index 9086eb1c70..ebdaba0152 100644
--- a/sysdeps/s390/s390-32/strncpy.S
+++ b/sysdeps/s390/s390-32/strncpy-z900.S
@@ -24,10 +24,12 @@
  * R4 = max of bytes to copy
  */
 
+#include <ifunc-strncpy.h>
 #include "sysdep.h"
 #include "asm-syntax.h"
 
-ENTRY(strncpy)
+#if HAVE_STRNCPY_Z900_G5
+ENTRY(STRNCPY_Z900_G5)
 	.text
 	st    %r2,24(%r15)          # save dst pointer
 	slr   %r2,%r3               # %r3 points to src, %r2+%r3 to dst
@@ -75,5 +77,13 @@ ENTRY(strncpy)
 	jo    .L9
 .Lexit: l     %r2,24(%r15)          # return dst pointer
 	br    %r14
-END(strncpy)
-libc_hidden_builtin_def (strncpy)
+END(STRNCPY_Z900_G5)
+
+# if ! HAVE_STRNCPY_IFUNC
+strong_alias (STRNCPY_Z900_G5, strncpy)
+# endif
+
+# if defined SHARED && IS_IN (libc)
+strong_alias (STRNCPY_Z900_G5, __GI_strncpy)
+# endif
+#endif