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			126 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			126 lines
		
	
	
		
			3.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* cpuid.c - test for CPU features */
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/*
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 *  GRUB  --  GRand Unified Bootloader
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 *  Copyright (C) 2006, 2007, 2009  Free Software Foundation, Inc.
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 *  Based on gcc/gcc/config/i386/driver-i386.c
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 *
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 *  GRUB is free software: you can redistribute it and/or modify
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 *  it under the terms of the GNU General Public License as published by
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 *  the Free Software Foundation, either version 3 of the License, or
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 *  (at your option) any later version.
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 *
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 *  GRUB is distributed in the hope that it will be useful,
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 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 *  GNU General Public License for more details.
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 *
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 *  You should have received a copy of the GNU General Public License
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 *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
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 */
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#include <grub/dl.h>
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#include <grub/misc.h>
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#include <grub/mm.h>
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#include <grub/env.h>
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#include <grub/command.h>
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#include <grub/extcmd.h>
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#include <grub/i386/cpuid.h>
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#include <grub/i18n.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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static const struct grub_arg_option options[] =
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  {
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    /* TRANSLATORS: "(default)" at the end means that this option is used if
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       no argument is specified.  */
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    {"long-mode", 'l', 0, N_("Check if CPU supports 64-bit (long) mode (default)."), 0, 0},
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    {"pae", 'p', 0, N_("Check if CPU supports Physical Address Extension."), 0, 0},
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    {0, 0, 0, 0, 0, 0}
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  };
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enum
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  {
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    MODE_LM = 0,
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    MODE_PAE = 1
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  };
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enum
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  {
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    bit_PAE = (1 << 6),
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  };
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enum
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  {
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    bit_LM = (1 << 29)
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  };
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unsigned char grub_cpuid_has_longmode = 0, grub_cpuid_has_pae = 0;
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static grub_err_t
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grub_cmd_cpuid (grub_extcmd_context_t ctxt,
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		int argc __attribute__ ((unused)),
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		char **args __attribute__ ((unused)))
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{
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  int val = 0;
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  if (ctxt->state[MODE_PAE].set)
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    val = grub_cpuid_has_pae;
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  else
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    val = grub_cpuid_has_longmode;
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  return val ? GRUB_ERR_NONE
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    /* TRANSLATORS: it's a standalone boolean value,
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       opposite of "true".  */
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    : grub_error (GRUB_ERR_TEST_FAILURE, N_("false"));
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}
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static grub_extcmd_t cmd;
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GRUB_MOD_INIT(cpuid)
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{
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#ifdef __x86_64__
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  /* grub-emu */
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  grub_cpuid_has_longmode = 1;
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  grub_cpuid_has_pae = 1;
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#else
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  unsigned int eax, ebx, ecx, edx;
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  unsigned int max_level;
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  unsigned int ext_level;
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  /* See if we can use cpuid.  */
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  asm volatile ("pushfl; pushfl; popl %0; movl %0,%1; xorl %2,%0;"
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		"pushl %0; popfl; pushfl; popl %0; popfl"
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		: "=&r" (eax), "=&r" (ebx)
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		: "i" (0x00200000));
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  if (((eax ^ ebx) & 0x00200000) == 0)
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    goto done;
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  /* Check the highest input value for eax.  */
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  grub_cpuid (0, eax, ebx, ecx, edx);
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  /* We only look at the first four characters.  */
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  max_level = eax;
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  if (max_level == 0)
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    goto done;
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  if (max_level >= 1)
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    {
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      grub_cpuid (1, eax, ebx, ecx, edx);
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      grub_cpuid_has_pae = !!(edx & bit_PAE);
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    }
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  grub_cpuid (0x80000000, eax, ebx, ecx, edx);
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  ext_level = eax;
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  if (ext_level < 0x80000000)
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    goto done;
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  grub_cpuid (0x80000001, eax, ebx, ecx, edx);
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  grub_cpuid_has_longmode = !!(edx & bit_LM);
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done:
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#endif
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  cmd = grub_register_extcmd ("cpuid", grub_cmd_cpuid, 0,
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			      "[-l]", N_("Check for CPU features."), options);
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}
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GRUB_MOD_FINI(cpuid)
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{
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  grub_unregister_extcmd (cmd);
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}
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