bfd/cpu-i386.c

   1 /* BFD support for the Intel 386 architecture.
   2    Copyright (C) 1992-2017 Free Software Foundation, Inc.
   3
   4    This file is part of BFD, the Binary File Descriptor library.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program 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
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  19    MA 02110-1301, USA.  */
  20
  21 #include "sysdep.h"
  22 #include "bfd.h"
  23 #include "libbfd.h"
  24 #include "libiberty.h"
  25
  26 extern void * bfd_arch_i386_short_nop_fill (bfd_size_type, bfd_boolean,
  27                                             bfd_boolean);
  28
  29 static const bfd_arch_info_type *
  30 bfd_i386_compatible (const bfd_arch_info_type *a,
  31                      const bfd_arch_info_type *b)
  32 {
  33   const bfd_arch_info_type *compat = bfd_default_compatible (a, b);
  34
  35   /* Don't allow mixing x64_32 with x86_64.  */
  36   if (compat
  37       && (a->mach & bfd_mach_x64_32) != (b->mach & bfd_mach_x64_32))
  38     compat = NULL;
  39
  40   return compat;
  41 }
  42
  43 /* Fill the buffer with zero or nop instruction if CODE is TRUE.  Use
  44    multi byte nop instructions if LONG_NOP is TRUE.  */
  45
  46 static void *
  47 bfd_arch_i386_fill (bfd_size_type count, bfd_boolean code,
  48                     bfd_boolean long_nop)
  49 {
  50   /* nop */
  51   static const char nop_1[] = { 0x90 };
  52   /* xchg %ax,%ax */
  53   static const char nop_2[] = { 0x66, 0x90 };
  54   /* nopl (%[re]ax) */
  55   static const char nop_3[] = { 0x0f, 0x1f, 0x00 };
  56   /* nopl 0(%[re]ax) */
  57   static const char nop_4[] = { 0x0f, 0x1f, 0x40, 0x00 };
  58   /* nopl 0(%[re]ax,%[re]ax,1) */
  59   static const char nop_5[] = { 0x0f, 0x1f, 0x44, 0x00, 0x00 };
  60   /* nopw 0(%[re]ax,%[re]ax,1) */
  61   static const char nop_6[] = { 0x66, 0x0f, 0x1f, 0x44, 0x00, 0x00 };
  62   /* nopl 0L(%[re]ax) */
  63   static const char nop_7[] = { 0x0f, 0x1f, 0x80, 0x00, 0x00, 0x00, 0x00 };
  64   /* nopl 0L(%[re]ax,%[re]ax,1) */
  65   static const char nop_8[] =
  66     { 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00};
  67   /* nopw 0L(%[re]ax,%[re]ax,1) */
  68   static const char nop_9[] =
  69     { 0x66, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
  70   /* nopw %cs:0L(%[re]ax,%[re]ax,1) */
  71   static const char nop_10[] =
  72     { 0x66, 0x2e, 0x0f, 0x1f, 0x84, 0x00, 0x00, 0x00, 0x00, 0x00 };
  73   static const char *const nops[] =
  74     { nop_1, nop_2, nop_3, nop_4, nop_5,
  75       nop_6, nop_7, nop_8, nop_9, nop_10 };
  76   bfd_size_type nop_size = long_nop ? ARRAY_SIZE (nops) : 2;
  77
  78   void *fill = bfd_malloc (count);
  79   if (fill == NULL)
  80     return fill;
  81
  82   if (code)
  83     {
  84       bfd_byte *p = fill;
  85       while (count >= nop_size)
  86         {
  87           memcpy (p, nops[nop_size - 1], nop_size);
  88           p += nop_size;
  89           count -= nop_size;
  90         }
  91       if (count != 0)
  92         memcpy (p, nops[count - 1], count);
  93     }
  94   else
  95     memset (fill, 0, count);
  96
  97   return fill;
  98 }
  99
 100 /* Fill the buffer with zero or short nop instruction if CODE is TRUE.  */
 101
 102 void *
 103 bfd_arch_i386_short_nop_fill (bfd_size_type count,
 104                               bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
 105                               bfd_boolean code)
 106 {
 107   return bfd_arch_i386_fill (count, code, FALSE);
 108 }
 109
 110 /* Fill the buffer with zero or long nop instruction if CODE is TRUE.  */
 111
 112 static void *
 113 bfd_arch_i386_long_nop_fill (bfd_size_type count,
 114                              bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
 115                              bfd_boolean code)
 116 {
 117   return bfd_arch_i386_fill (count, code, TRUE);
 118 }
 119
 120 /* Fill the buffer with zero, or one-byte nop instructions if CODE is TRUE.  */
 121
 122 static void *
 123 bfd_arch_i386_onebyte_nop_fill (bfd_size_type count,
 124                                 bfd_boolean is_bigendian ATTRIBUTE_UNUSED,
 125                                 bfd_boolean code)
 126 {
 127   void *fill = bfd_malloc (count);
 128   if (fill != NULL)
 129     memset (fill, code ? 0x90 : 0, count);
 130   return fill;
 131 }
 132
 133
 134 static const bfd_arch_info_type bfd_x64_32_nacl_arch =
 135 {
 136   64, /* 64 bits in a word */
 137   64, /* 64 bits in an address */
 138   8,  /* 8 bits in a byte */
 139   bfd_arch_i386,
 140   bfd_mach_x64_32_nacl,
 141   "i386",
 142   "i386:x64-32:nacl",
 143   3,
 144   FALSE,
 145   bfd_i386_compatible,
 146   bfd_default_scan,
 147   bfd_arch_i386_onebyte_nop_fill,
 148   NULL
 149 };
 150
 151 static const bfd_arch_info_type bfd_x86_64_nacl_arch =
 152 {
 153   64, /* 64 bits in a word */
 154   64, /* 64 bits in an address */
 155   8,  /* 8 bits in a byte */
 156   bfd_arch_i386,
 157   bfd_mach_x86_64_nacl,
 158   "i386",
 159   "i386:x86-64:nacl",
 160   3,
 161   FALSE,
 162   bfd_i386_compatible,
 163   bfd_default_scan,
 164   bfd_arch_i386_onebyte_nop_fill,
 165   &bfd_x64_32_nacl_arch
 166 };
 167
 168 const bfd_arch_info_type bfd_i386_nacl_arch =
 169 {
 170   32,   /* 32 bits in a word */
 171   32,   /* 32 bits in an address */
 172   8,    /* 8 bits in a byte */
 173   bfd_arch_i386,
 174   bfd_mach_i386_i386_nacl,
 175   "i386",
 176   "i386:nacl",
 177   3,
 178   TRUE,
 179   bfd_i386_compatible,
 180   bfd_default_scan,
 181   bfd_arch_i386_onebyte_nop_fill,
 182   &bfd_x86_64_nacl_arch
 183 };
 184
 185 static const bfd_arch_info_type bfd_x64_32_arch_intel_syntax =
 186 {
 187   64, /* 64 bits in a word */
 188   64, /* 64 bits in an address */
 189   8,  /* 8 bits in a byte */
 190   bfd_arch_i386,
 191   bfd_mach_x64_32_intel_syntax,
 192   "i386:intel",
 193   "i386:x64-32:intel",
 194   3,
 195   FALSE,
 196   bfd_i386_compatible,
 197   bfd_default_scan,
 198   bfd_arch_i386_long_nop_fill,
 199   &bfd_i386_nacl_arch
 200 };
 201
 202 static const bfd_arch_info_type bfd_x86_64_arch_intel_syntax =
 203 {
 204   64, /* 64 bits in a word */
 205   64, /* 64 bits in an address */
 206   8,  /* 8 bits in a byte */
 207   bfd_arch_i386,
 208   bfd_mach_x86_64_intel_syntax,
 209   "i386:intel",
 210   "i386:x86-64:intel",
 211   3,
 212   FALSE,
 213   bfd_i386_compatible,
 214   bfd_default_scan,
 215   bfd_arch_i386_long_nop_fill,
 216   &bfd_x64_32_arch_intel_syntax,
 217 };
 218
 219 static const bfd_arch_info_type bfd_i386_arch_intel_syntax =
 220 {
 221   32,   /* 32 bits in a word */
 222   32,   /* 32 bits in an address */
 223   8,    /* 8 bits in a byte */
 224   bfd_arch_i386,
 225   bfd_mach_i386_i386_intel_syntax,
 226   "i386:intel",
 227   "i386:intel",
 228   3,
 229   TRUE,
 230   bfd_i386_compatible,
 231   bfd_default_scan,
 232   bfd_arch_i386_short_nop_fill,
 233   &bfd_x86_64_arch_intel_syntax
 234 };
 235
 236 static const bfd_arch_info_type i8086_arch =
 237 {
 238   32,   /* 32 bits in a word */
 239   32,   /* 32 bits in an address (well, not really) */
 240   8,    /* 8 bits in a byte */
 241   bfd_arch_i386,
 242   bfd_mach_i386_i8086,
 243   "i8086",
 244   "i8086",
 245   3,
 246   FALSE,
 247   bfd_i386_compatible,
 248   bfd_default_scan,
 249   bfd_arch_i386_short_nop_fill,
 250   &bfd_i386_arch_intel_syntax
 251 };
 252
 253 static const bfd_arch_info_type bfd_x64_32_arch =
 254 {
 255   64, /* 64 bits in a word */
 256   64, /* 64 bits in an address */
 257   8,  /* 8 bits in a byte */
 258   bfd_arch_i386,
 259   bfd_mach_x64_32,
 260   "i386",
 261   "i386:x64-32",
 262   3,
 263   FALSE,
 264   bfd_i386_compatible,
 265   bfd_default_scan,
 266   bfd_arch_i386_long_nop_fill,
 267   &i8086_arch
 268 };
 269
 270 static const bfd_arch_info_type bfd_x86_64_arch =
 271 {
 272   64, /* 64 bits in a word */
 273   64, /* 64 bits in an address */
 274   8,  /* 8 bits in a byte */
 275   bfd_arch_i386,
 276   bfd_mach_x86_64,
 277   "i386",
 278   "i386:x86-64",
 279   3,
 280   FALSE,
 281   bfd_i386_compatible,
 282   bfd_default_scan,
 283   bfd_arch_i386_long_nop_fill,
 284   &bfd_x64_32_arch
 285 };
 286
 287 const bfd_arch_info_type bfd_i386_arch =
 288 {
 289   32,   /* 32 bits in a word */
 290   32,   /* 32 bits in an address */
 291   8,    /* 8 bits in a byte */
 292   bfd_arch_i386,
 293   bfd_mach_i386_i386,
 294   "i386",
 295   "i386",
 296   3,
 297   TRUE,
 298   bfd_i386_compatible,
 299   bfd_default_scan,
 300   bfd_arch_i386_short_nop_fill,
 301   &bfd_x86_64_arch
 302 };