sysdeps/s390/s390-64/multiarch/ifunc-resolve.c

   1 /* IFUNC resolver function for CPU specific functions.
   2    64 bit S/390 version.
   3    Copyright (C) 2012-2014 Free Software Foundation, Inc.
   4    This file is part of the GNU C Library.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <unistd.h>
  21 #include <dl-procinfo.h>
  22
  23 #define STFLE_BITS_Z10  34 /* General instructions extension */
  24 #define STFLE_BITS_Z196 45 /* Distinct operands, pop ... */
  25
  26 #ifndef NOT_IN_libc
  27
  28 #define IFUNC_RESOLVE(FUNC)                                             \
  29   asm (".globl " #FUNC "\n\t"                                           \
  30        ".type  " #FUNC ",@gnu_indirect_function\n\t"                    \
  31        ".set   " #FUNC ",resolve_" #FUNC "\n\t"                         \
  32        ".globl __GI_" #FUNC "\n\t"                                      \
  33        ".set   __GI_" #FUNC "," #FUNC "\n");                            \
  34                                                                         \
  35   /* Make the declarations of the optimized functions hidden in order
  36      to prevent GOT slots being generated for them. */                  \
  37   extern void *FUNC##_z196 attribute_hidden;                            \
  38   extern void *FUNC##_z10 attribute_hidden;                             \
  39   extern void *FUNC##_z900 attribute_hidden;                            \
  40                                                                         \
  41   void *resolve_##FUNC (unsigned long int dl_hwcap)                     \
  42   {                                                                     \
  43     if (dl_hwcap & HWCAP_S390_STFLE)                                    \
  44       {                                                                 \
  45         /* We want just 1 double word to be returned.  */               \
  46         register unsigned long reg0 asm("0") = 0;                       \
  47         unsigned long stfle_bits;                                       \
  48                                                                         \
  49         asm volatile(".machine push"        "\n\t"                      \
  50                      ".machine \"z9-109\""  "\n\t"                      \
  51                      "stfle %0"             "\n\t"                      \
  52                      ".machine pop"         "\n"                        \
  53                      : "=QS" (stfle_bits), "+d" (reg0)                  \
  54                      : : "cc");                                         \
  55                                                                         \
  56         if ((stfle_bits & (1UL << (63 - STFLE_BITS_Z196))) != 0)        \
  57           return &FUNC##_z196;                                          \
  58         else if ((stfle_bits & (1UL << (63 - STFLE_BITS_Z10))) != 0)    \
  59           return &FUNC##_z10;                                           \
  60         else                                                            \
  61           return &FUNC##_z900;                                          \
  62       }                                                                 \
  63     else                                                                \
  64       return &FUNC##_z900;                                              \
  65   }
  66
  67 IFUNC_RESOLVE(memset)
  68 IFUNC_RESOLVE(memcmp)
  69 asm(".weak bcmp ; bcmp = memcmp");
  70
  71 /* In the static lib memcpy is needed before the reloc is resolved.  */
  72 #ifdef SHARED
  73 IFUNC_RESOLVE(memcpy)
  74 #endif
  75
  76 #endif