81 lines
2.8 KiB
C
81 lines
2.8 KiB
C
|
/*******************************************************************************
|
||
|
|
|
||
|
|
Copyright(C) Jonas 'Sortie' Termansen 2013.
|
||
|
|
|
||
|
|
This file is part of Sortix.
|
||
|
|
|
||
|
|
Sortix 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.
|
||
|
|
|
||
|
|
Sortix 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
|
||
|
|
Sortix. If not, see <http://www.gnu.org/licenses/>.
|
||
|
|
|
||
|
|
sortix/kernel/cpuid.h
|
||
|
|
Interface to using the cpuid instruction.
|
||
|
|
|
||
|
|
*******************************************************************************/
|
||
|
|
|
||
|
|
#ifndef INCLUDE_SORTIX_KERNEL_CPUID_H
|
||
|
|
#define INCLUDE_SORTIX_KERNEL_CPUID_H
|
||
|
|
|
||
|
|
#include <stdint.h>
|
||
|
|
|
||
|
|
namespace Sortix {
|
||
|
|
|
||
|
|
#if defined(__i386__) || defined(__x86_64__)
|
||
|
|
|
||
|
|
__attribute__((const))
|
||
|
|
__attribute__((unused))
|
||
|
|
static inline bool IsCPUIdSupported()
|
||
|
|
{
|
||
|
|
#if defined(__x86_64__)
|
||
|
|
// TODO: Isn't this always supported under x86_64?
|
||
|
|
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");
|
||
|
|
#elif defined(__i386__)
|
||
|
|
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");
|
||
|
|
#endif
|
||
|
|
return id_supported != 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
#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))
|
||
|
|
|
||
|
|
#endif
|
||
|
|
|
||
|
|
} // namespace Sortix
|
||
|
|
|
||
|
|
#endif
|