7 files changed, 110 insertions, 20 deletions
diff --git a/sysdeps/s390/Makefile b/sysdeps/s390/Makefile
index 9e7d5625c9..3aaf5a0d40 100644
--- a/sysdeps/s390/Makefile
+++ b/sysdeps/s390/Makefile
@@ -68,5 +68,6 @@ sysdep_routines += bzero memset memset-z900 \
 		   stpncpy stpncpy-vx stpncpy-c \
 		   strcat strcat-vx strcat-c \
 		   strncat strncat-vx strncat-c \
-		   strcmp strcmp-vx strcmp-z900
+		   strcmp strcmp-vx strcmp-z900 \
+		   strncmp strncmp-vx strncmp-c
 endif
diff --git a/sysdeps/s390/ifunc-strncmp.h b/sysdeps/s390/ifunc-strncmp.h
new file mode 100644
index 0000000000..511b3e9720
--- /dev/null
+++ b/sysdeps/s390/ifunc-strncmp.h
@@ -0,0 +1,52 @@
+/* strncmp variant information on S/390 version.
+   Copyright (C) 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/>.  */
+
+#if defined USE_MULTIARCH && IS_IN (libc)		\
+  && ! defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define HAVE_STRNCMP_IFUNC	1
+#else
+# define HAVE_STRNCMP_IFUNC	0
+#endif
+
+#ifdef HAVE_S390_VX_ASM_SUPPORT
+# define HAVE_STRNCMP_IFUNC_AND_VX_SUPPORT HAVE_STRNCMP_IFUNC
+#else
+# define HAVE_STRNCMP_IFUNC_AND_VX_SUPPORT 0
+#endif
+
+#if defined HAVE_S390_MIN_Z13_ZARCH_ASM_SUPPORT
+# define STRNCMP_DEFAULT	STRNCMP_Z13
+# define HAVE_STRNCMP_C		0
+# define HAVE_STRNCMP_Z13	1
+#else
+# define STRNCMP_DEFAULT	STRNCMP_C
+# define HAVE_STRNCMP_C		1
+# define HAVE_STRNCMP_Z13	HAVE_STRNCMP_IFUNC_AND_VX_SUPPORT
+#endif
+
+#if HAVE_STRNCMP_C
+# define STRNCMP_C		__strncmp_c
+#else
+# define STRNCMP_C		NULL
+#endif
+
+#if HAVE_STRNCMP_Z13
+# define STRNCMP_Z13		__strncmp_vx
+#else
+# define STRNCMP_Z13		NULL
+#endif
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 97421a4996..381376bf9f 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -1,6 +1,5 @@
 ifeq ($(subdir),string)
-sysdep_routines += strncmp strncmp-vx strncmp-c \
-		   strchr strchr-vx strchr-c \
+sysdep_routines += strchr strchr-vx strchr-c \
 		   strchrnul strchrnul-vx strchrnul-c \
 		   strrchr strrchr-vx strrchr-c \
 		   strspn strspn-vx strspn-c \
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index 44637c431b..d982de5788 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -35,6 +35,7 @@
 #include <ifunc-strcat.h>
 #include <ifunc-strncat.h>
 #include <ifunc-strcmp.h>
+#include <ifunc-strncmp.h>
 
 /* Maximum number of IFUNC implementations.  */
 #define MAX_IFUNC	3
@@ -281,6 +282,18 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 		)
 #endif /* HAVE_STRCMP_IFUNC  */
 
+#if HAVE_STRNCMP_IFUNC
+    IFUNC_IMPL (i, name, strncmp,
+# if HAVE_STRNCMP_Z13
+		IFUNC_IMPL_ADD (array, i, strncmp,
+				dl_hwcap & HWCAP_S390_VX, STRNCMP_Z13)
+# endif
+# if HAVE_STRNCMP_C
+		IFUNC_IMPL_ADD (array, i, strncmp, 1, STRNCMP_C)
+# endif
+		)
+#endif /* HAVE_STRNCMP_IFUNC  */
+
 #ifdef HAVE_S390_VX_ASM_SUPPORT
 
 # define IFUNC_VX_IMPL(FUNC)						\
@@ -307,7 +320,6 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
 
   IFUNC_VX_IMPL (wcscmp);
 
-  IFUNC_VX_IMPL (strncmp);
   IFUNC_VX_IMPL (wcsncmp);
 
   IFUNC_VX_IMPL (strchr);
diff --git a/sysdeps/s390/multiarch/strncmp-c.c b/sysdeps/s390/strncmp-c.c
index e54277ec1b..c7ffdb03e3 100644
--- a/sysdeps/s390/multiarch/strncmp-c.c
+++ b/sysdeps/s390/strncmp-c.c
@@ -16,13 +16,17 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
-# define STRNCMP  __strncmp_c
-# ifdef SHARED
-#  undef libc_hidden_builtin_def
-#  define libc_hidden_builtin_def(name)			\
+#include <ifunc-strncmp.h>
+
+#if HAVE_STRNCMP_C
+# if HAVE_STRNCMP_IFUNC
+#  define STRNCMP STRNCMP_C
+#  if defined SHARED && IS_IN (libc)
+#   undef libc_hidden_builtin_def
+#   define libc_hidden_builtin_def(name)			\
   __hidden_ver1 (__strncmp_c, __GI_strncmp, __strncmp_c);
-# endif /* SHARED */
+#  endif
+# endif
 
 # include <string/strncmp.c>
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+#endif
diff --git a/sysdeps/s390/multiarch/strncmp-vx.S b/sysdeps/s390/strncmp-vx.S
index 168fd657da..f557afb336 100644
--- a/sysdeps/s390/multiarch/strncmp-vx.S
+++ b/sysdeps/s390/strncmp-vx.S
@@ -16,7 +16,9 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+#include <ifunc-strncmp.h>
+
+#if HAVE_STRNCMP_Z13
 
 # include "sysdep.h"
 # include "asm-syntax.h"
@@ -37,7 +39,7 @@
    -v17=part of s2
    -v18=index of unequal
 */
-ENTRY(__strncmp_vx)
+ENTRY(STRNCMP_Z13)
 	.machine "z13"
 	.machinemode "zarch_nohighgprs"
 
@@ -133,5 +135,14 @@ ENTRY(__strncmp_vx)
 .Lend_equal:
 	lghi	%r2,0
 	br	%r14
-END(__strncmp_vx)
-#endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */
+END(STRNCMP_Z13)
+
+# if ! HAVE_STRNCMP_IFUNC
+strong_alias (STRNCMP_Z13, strncmp)
+# endif
+
+# if ! HAVE_STRNCMP_C && defined SHARED && IS_IN (libc)
+strong_alias (STRNCMP_Z13, __GI_strncmp)
+# endif
+
+#endif /* HAVE_STRNCMP_Z13  */
diff --git a/sysdeps/s390/multiarch/strncmp.c b/sysdeps/s390/strncmp.c
index 0ec472c3b0..71351273c4 100644
--- a/sysdeps/s390/multiarch/strncmp.c
+++ b/sysdeps/s390/strncmp.c
@@ -16,7 +16,9 @@
    License along with the GNU C Library; if not, see
    <http://www.gnu.org/licenses/>.  */
 
-#if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)
+#include <ifunc-strncmp.h>
+
+#if HAVE_STRNCMP_IFUNC
 # define strncmp __redirect_strncmp
 /* Omit the strncmp inline definitions because it would redefine strncmp.  */
 # define __NO_STRING_INLINES
@@ -24,8 +26,17 @@
 # undef strncmp
 # include <ifunc-resolve.h>
 
-s390_vx_libc_ifunc2_redirected (__redirect_strncmp, __strncmp, strncmp)
+# if HAVE_STRNCMP_C
+extern __typeof (__redirect_strncmp) STRNCMP_C attribute_hidden;
+# endif
+
+# if HAVE_STRNCMP_Z13
+extern __typeof (__redirect_strncmp) STRNCMP_Z13 attribute_hidden;
+# endif
 
-#else
-# include <string/strncmp.c>
-#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc)) */
+s390_libc_ifunc_expr (__redirect_strncmp, strncmp,
+		      (HAVE_STRNCMP_Z13 && (hwcap & HWCAP_S390_VX))
+		      ? STRNCMP_Z13
+		      : STRNCMP_DEFAULT
+		      )
+#endif /* HAVE_STRNCMP_IFUNC  */