sysdeps/x86_64/multiarch/init-arch.c

   1 /* Initialize CPU feature data.
   2    This file is part of the GNU C Library.
   3    Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
   4    Contributed by Ulrich Drepper <drepper@redhat.com>.
   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, write to the Free
  18    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  19    02111-1307 USA.  */
  20
  21 #include <atomic.h>
  22 #include <cpuid.h>
  23 #include "init-arch.h"
  24
  25
  26 struct cpu_features __cpu_features attribute_hidden;
  27
  28
  29 static void
  30 get_common_indeces (unsigned int *family, unsigned int *model)
  31 {
  32   __cpuid (1, __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax,
  33            __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ebx,
  34            __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx,
  35            __cpu_features.cpuid[COMMON_CPUID_INDEX_1].edx);
  36
  37   unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax;
  38   *family = (eax >> 8) & 0x0f;
  39   *model = (eax >> 4) & 0x0f;
  40 }
  41
  42
  43 void
  44 __init_cpu_features (void)
  45 {
  46   unsigned int ebx;
  47   unsigned int ecx;
  48   unsigned int edx;
  49   unsigned int family = 0;
  50   unsigned int model = 0;
  51   enum cpu_features_kind kind;
  52
  53   __cpuid (0, __cpu_features.max_cpuid, ebx, ecx, edx);
  54
  55   /* This spells out "GenuineIntel".  */
  56   if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
  57     {
  58       kind = arch_kind_intel;
  59
  60       get_common_indeces (&family, &model);
  61
  62       unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax;
  63       unsigned int extended_family = (eax >> 20) & 0xff;
  64       unsigned int extended_model = (eax >> 12) & 0xf0;
  65       if (family == 0x0f)
  66         {
  67           family += extended_family;
  68           model += extended_model;
  69         }
  70       else if (family == 0x06)
  71         {
  72           model += extended_model;
  73           switch (model)
  74             {
  75             case 0x1a:
  76             case 0x1e:
  77             case 0x1f:
  78             case 0x25:
  79             case 0x2e:
  80             case 0x2f:
  81               /* Rep string instructions are fast on Intel Core i3, i5
  82                  and i7.  */
  83               __cpu_features.feature[index_Fast_Rep_String]
  84                 |= bit_Fast_Rep_String;
  85               break;
  86             }
  87         }
  88     }
  89   /* This spells out "AuthenticAMD".  */
  90   else if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
  91     {
  92       kind = arch_kind_amd;
  93
  94       get_common_indeces (&family, &model);
  95     }
  96   else
  97     kind = arch_kind_other;
  98
  99   __cpu_features.family = family;
 100   __cpu_features.model = model;
 101   atomic_write_barrier ();
 102   __cpu_features.kind = kind;
 103 }
 104
 105 #undef __get_cpu_features
 106
 107 const struct cpu_features *
 108 __get_cpu_features (void)
 109 {
 110   if (__cpu_features.kind == arch_kind_unknown)
 111     __init_cpu_features ();
 112
 113   return &__cpu_features;
 114 }