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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2009 Free Software Foundation, Inc.
*
* 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/>.
*/
#ifndef GRUB_CPU_CPUID_HEADER
#define GRUB_CPU_CPUID_HEADER 1
extern unsigned char grub_cpuid_has_longmode;
extern unsigned char grub_cpuid_has_pae;
#ifdef __x86_64__
static __inline int
grub_cpu_is_cpuid_supported (void)
{
grub_uint64_t id_supported;
__asm__ ("pushfq\n\t"
"popq %%rax /* Get EFLAGS into EAX */\n\t"
"movq %%rax, %%rcx /* Save original flags in ECX */\n\t"
"xorq $0x200000, %%rax /* Flip ID bit in EFLAGS */\n\t"
"pushq %%rax /* Store modified EFLAGS on stack */\n\t"
"popfq /* Replace current EFLAGS */\n\t"
"pushfq /* Read back the EFLAGS */\n\t"
"popq %%rax /* Get EFLAGS into EAX */\n\t"
"xorq %%rcx, %%rax /* Check if flag could be modified */\n\t"
: "=a" (id_supported)
: /* No inputs. */
: /* Clobbered: */ "%rcx");
return id_supported != 0;
}
#else
static __inline int
grub_cpu_is_cpuid_supported (void)
{
grub_uint32_t id_supported;
__asm__ ("pushfl\n\t"
"popl %%eax /* Get EFLAGS into EAX */\n\t"
"movl %%eax, %%ecx /* Save original flags in ECX */\n\t"
"xorl $0x200000, %%eax /* Flip ID bit in EFLAGS */\n\t"
"pushl %%eax /* Store modified EFLAGS on stack */\n\t"
"popfl /* Replace current EFLAGS */\n\t"
"pushfl /* Read back the EFLAGS */\n\t"
"popl %%eax /* Get EFLAGS into EAX */\n\t"
"xorl %%ecx, %%eax /* Check if flag could be modified */\n\t"
: "=a" (id_supported)
: /* No inputs. */
: /* Clobbered: */ "%rcx");
return id_supported != 0;
}
#endif
#ifdef __PIC__
#define grub_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))
#else
#define grub_cpuid(num,a,b,c,d) \
asm volatile ("cpuid" \
: "=a" (a), "=b" (b), "=c" (c), "=d" (d) \
: "0" (num))
#endif
#endif
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