S/390: Add support for STT_GNU_IFUNC symbols.

Add support for STT_GNU_IFUNC symbols and the new R_390_IRELATIVE
relocation.  Provide optimized version of memcpy, memset, and memcmp
for z10 and z196.

1 files changed, 74 insertions, 0 deletions

diff --git a/sysdeps/s390/s390-64/multiarch/ifunc-resolve.c b/sysdeps/s390/s390-64/multiarch/ifunc-resolve.c
new file mode 100644
index 0000000000..f980bc9390
--- /dev/null
+++ b/sysdeps/s390/s390-64/multiarch/ifunc-resolve.c
@@ -0,0 +1,74 @@
+/* IFUNC resolver function for CPU specific functions.
+   64 bit S/390 version.
+   Copyright (C) 2012 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/>.  */
+
+#include <unistd.h>
+#include <dl-procinfo.h>
+
+#define STFLE_BITS_Z10  34 /* General instructions extension */
+#define STFLE_BITS_Z196 45 /* Distinct operands, pop ... */
+
+#ifndef NOT_IN_libc
+
+#define IFUNC_RESOLVE(FUNC)						\
+  asm (".globl " #FUNC "\n\t"						\
+       ".type  " #FUNC ",@gnu_indirect_function\n\t"			\
+       ".set   " #FUNC ",resolve_" #FUNC "\n\t"				\
+       ".globl __GI_" #FUNC "\n\t"					\
+       ".set   __GI_" #FUNC "," #FUNC "\n");				\
+									\
+  extern void *FUNC##_z10;						\
+  extern void *FUNC##_z196;						\
+  extern void *FUNC##_z900;						\
+									\
+  void *resolve_##FUNC (unsigned long int dl_hwcap)			\
+  {									\
+    if (dl_hwcap & HWCAP_S390_STFLE)					\
+      {									\
+	/* We want just 1 double word to be returned.  */		\
+	register unsigned long reg0 asm("0") = 0;			\
+	unsigned long stfle_bits;					\
+									\
+	asm volatile(".machine push"        "\n\t"			\
+		     ".machine \"z9-109\""  "\n\t"			\
+		     "stfle %0"             "\n\t"			\
+		     ".machine pop"         "\n"			\
+		     : "=QS" (stfle_bits), "+d" (reg0)			\
+		     : : "cc");						\
+									\
+	if ((stfle_bits & (1UL << (63 - STFLE_BITS_Z196))) != 0)	\
+	  return &FUNC##_z196;						\
+	else if ((stfle_bits & (1UL << (63 - STFLE_BITS_Z10))) != 0)	\
+	  return &FUNC##_z10;						\
+	else								\
+	  return &FUNC##_z900;						\
+      }									\
+    else								\
+      return &FUNC##_z900;						\
+  }
+
+IFUNC_RESOLVE(memset)
+IFUNC_RESOLVE(memcmp)
+asm(".weak bcmp ; bcmp = memcmp");
+
+/* In the static lib memcpy is needed before the reloc is resolved.  */
+#ifdef SHARED
+IFUNC_RESOLVE(memcpy)
+#endif
+
+#endif