arch/all-pc/boot/grub2-aros/grub-core/commands/i386/cpuid.c

   1 /* cpuid.c - test for CPU features */
   2 /*
   3  *  GRUB  --  GRand Unified Bootloader
   4  *  Copyright (C) 2006, 2007, 2009  Free Software Foundation, Inc.
   5  *  Based on gcc/gcc/config/i386/driver-i386.c
   6  *
   7  *  GRUB is free software: you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation, either version 3 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  GRUB is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include <grub/dl.h>
  22 #include <grub/misc.h>
  23 #include <grub/mm.h>
  24 #include <grub/env.h>
  25 #include <grub/command.h>
  26 #include <grub/extcmd.h>
  27 #include <grub/i386/cpuid.h>
  28 #include <grub/i18n.h>
  29
  30 GRUB_MOD_LICENSE ("GPLv3+");
  31
  32 static const struct grub_arg_option options[] =
  33   {
  34     /* TRANSLATORS: "(default)" at the end means that this option is used if
  35        no argument is specified.  */
  36     {"long-mode", 'l', 0, N_("Check if CPU supports 64-bit (long) mode (default)."), 0, 0},
  37     {"pae", 'p', 0, N_("Check if CPU supports Physical Address Extension."), 0, 0},
  38     {0, 0, 0, 0, 0, 0}
  39   };
  40
  41 enum
  42   {
  43     MODE_LM = 0,
  44     MODE_PAE = 1
  45   };
  46
  47 enum
  48   {
  49     bit_PAE = (1 << 6),
  50   };
  51 enum
  52   {
  53     bit_LM = (1 << 29)
  54   };
  55
  56 unsigned char grub_cpuid_has_longmode = 0, grub_cpuid_has_pae = 0;
  57
  58 static grub_err_t
  59 grub_cmd_cpuid (grub_extcmd_context_t ctxt,
  60                 int argc __attribute__ ((unused)),
  61                 char **args __attribute__ ((unused)))
  62 {
  63   int val = 0;
  64   if (ctxt->state[MODE_PAE].set)
  65     val = grub_cpuid_has_pae;
  66   else
  67     val = grub_cpuid_has_longmode;
  68   return val ? GRUB_ERR_NONE
  69     /* TRANSLATORS: it's a standalone boolean value,
  70        opposite of "true".  */
  71     : grub_error (GRUB_ERR_TEST_FAILURE, N_("false"));
  72 }
  73
  74 static grub_extcmd_t cmd;
  75
  76 GRUB_MOD_INIT(cpuid)
  77 {
  78 #ifdef __x86_64__
  79   /* grub-emu */
  80   grub_cpuid_has_longmode = 1;
  81   grub_cpuid_has_pae = 1;
  82 #else
  83   unsigned int eax, ebx, ecx, edx;
  84   unsigned int max_level;
  85   unsigned int ext_level;
  86
  87   /* See if we can use cpuid.  */
  88   asm volatile ("pushfl; pushfl; popl %0; movl %0,%1; xorl %2,%0;"
  89                 "pushl %0; popfl; pushfl; popl %0; popfl"
  90                 : "=&r" (eax), "=&r" (ebx)
  91                 : "i" (0x00200000));
  92   if (((eax ^ ebx) & 0x00200000) == 0)
  93     goto done;
  94
  95   /* Check the highest input value for eax.  */
  96   grub_cpuid (0, eax, ebx, ecx, edx);
  97   /* We only look at the first four characters.  */
  98   max_level = eax;
  99   if (max_level == 0)
 100     goto done;
 101
 102   if (max_level >= 1)
 103     {
 104       grub_cpuid (1, eax, ebx, ecx, edx);
 105       grub_cpuid_has_pae = !!(edx & bit_PAE);
 106     }
 107
 108   grub_cpuid (0x80000000, eax, ebx, ecx, edx);
 109   ext_level = eax;
 110   if (ext_level < 0x80000000)
 111     goto done;
 112
 113   grub_cpuid (0x80000001, eax, ebx, ecx, edx);
 114   grub_cpuid_has_longmode = !!(edx & bit_LM);
 115 done:
 116 #endif
 117
 118   cmd = grub_register_extcmd ("cpuid", grub_cmd_cpuid, 0,
 119                               "[-l]", N_("Check for CPU features."), options);
 120 }
 121
 122 GRUB_MOD_FINI(cpuid)
 123 {
 124   grub_unregister_extcmd (cmd);
 125 }