grub/grub-core/commands/i386/cpuid.c
Vladimir 'phcoder' Serbinenko ed80f7d586 * include/grub/command.h (GRUB_COMMAND_FLAG_CMDLINE): Removed. All
users updated.
	(GRUB_COMMAND_FLAG_MENU): Likewise.
	(GRUB_COMMAND_FLAG_BOTH): Likewise.
	(GRUB_COMMAND_FLAG_TITLE): Removed.
	(GRUB_COMMAND_FLAG_NO_ECHO): Likewise.
	(GRUB_COMMAND_FLAG_EXTCMD): Moved into enum.
	(GRUB_COMMAND_FLAG_DYNCMD): Likewise.
	(GRUB_COMMAND_FLAG_BLOCKS): Likewise.
	(grub_command_flags_t): New enum. All users updated.
2010-09-14 23:06:01 +02:00

98 lines
2.6 KiB
C

/* cpuid.c - test for CPU features */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2006, 2007, 2009 Free Software Foundation, Inc.
* Based on gcc/gcc/config/i386/driver-i386.c
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/dl.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/env.h>
#include <grub/command.h>
#include <grub/extcmd.h>
#include <grub/i386/cpuid.h>
#include <grub/i18n.h>
#define cpuid(num,a,b,c,d) \
asm volatile ("xchgl %%ebx, %1; cpuid; xchgl %%ebx, %1" \
: "=a" (a), "=r" (b), "=c" (c), "=d" (d) \
: "0" (num))
static const struct grub_arg_option options[] =
{
{"long-mode", 'l', 0, N_("Check for long mode flag (default)."), 0, 0},
{0, 0, 0, 0, 0, 0}
};
#define bit_LM (1 << 29)
unsigned char grub_cpuid_has_longmode = 0;
static grub_err_t
grub_cmd_cpuid (grub_extcmd_context_t ctxt __attribute__ ((unused)),
int argc __attribute__ ((unused)),
char **args __attribute__ ((unused)))
{
return grub_cpuid_has_longmode ? GRUB_ERR_NONE
: grub_error (GRUB_ERR_TEST_FAILURE, "false");
}
static grub_extcmd_t cmd;
GRUB_MOD_INIT(cpuid)
{
#ifdef __x86_64__
/* grub-emu */
grub_cpuid_has_longmode = 1;
#else
unsigned int eax, ebx, ecx, edx;
unsigned int max_level;
unsigned int ext_level;
/* See if we can use cpuid. */
asm volatile ("pushfl; pushfl; popl %0; movl %0,%1; xorl %2,%0;"
"pushl %0; popfl; pushfl; popl %0; popfl"
: "=&r" (eax), "=&r" (ebx)
: "i" (0x00200000));
if (((eax ^ ebx) & 0x00200000) == 0)
goto done;
/* Check the highest input value for eax. */
cpuid (0, eax, ebx, ecx, edx);
/* We only look at the first four characters. */
max_level = eax;
if (max_level == 0)
goto done;
cpuid (0x80000000, eax, ebx, ecx, edx);
ext_level = eax;
if (ext_level < 0x80000000)
goto done;
cpuid (0x80000001, eax, ebx, ecx, edx);
grub_cpuid_has_longmode = !!(edx & bit_LM);
done:
#endif
cmd = grub_register_extcmd ("cpuid", grub_cmd_cpuid, 0,
"[-l]", N_("Check for CPU features."), options);
}
GRUB_MOD_FINI(cpuid)
{
grub_unregister_extcmd (cmd);
}