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/*
* Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program 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 2 of the
* License, or any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <ipxe/cpuid.h>
/** @file
*
* x86 CPU feature detection
*
*/
/**
* Check whether or not CPUID instruction is supported
*
* @ret is_supported CPUID instruction is supported
*/
int cpuid_is_supported ( void ) {
unsigned long original;
unsigned long inverted;
__asm__ ( "pushf\n\t"
"pushf\n\t"
"pop %0\n\t"
"mov %0,%1\n\t"
"xor %2,%1\n\t"
"push %1\n\t"
"popf\n\t"
"pushf\n\t"
"pop %1\n\t"
"popf\n\t"
: "=&r" ( original ), "=&r" ( inverted )
: "ir" ( CPUID_FLAG ) );
return ( ( original ^ inverted ) & CPUID_FLAG );
}
/**
* Get Intel-defined x86 CPU features
*
* @v features x86 CPU features to fill in
*/
static void x86_intel_features ( struct x86_features *features ) {
uint32_t max_level;
uint32_t discard_a;
uint32_t discard_b;
uint32_t discard_c;
uint32_t discard_d;
/* Check that features are available via CPUID */
cpuid ( CPUID_VENDOR_ID, &max_level, &discard_b, &discard_c,
&discard_d );
if ( max_level < CPUID_FEATURES ) {
DBGC ( features, "CPUID has no Intel-defined features (max "
"level %08x)\n", max_level );
return;
}
/* Get features */
cpuid ( CPUID_FEATURES, &discard_a, &discard_b,
&features->intel.ecx, &features->intel.edx );
DBGC ( features, "CPUID Intel features: %%ecx=%08x, %%edx=%08x\n",
features->intel.ecx, features->intel.edx );
}
/**
* Get AMD-defined x86 CPU features
*
* @v features x86 CPU features to fill in
*/
static void x86_amd_features ( struct x86_features *features ) {
uint32_t max_level;
uint32_t discard_a;
uint32_t discard_b;
uint32_t discard_c;
uint32_t discard_d;
/* Check that features are available via CPUID */
cpuid ( CPUID_AMD_MAX_FN, &max_level, &discard_b, &discard_c,
&discard_d );
if ( ( max_level & CPUID_AMD_CHECK_MASK ) != CPUID_AMD_CHECK ) {
DBGC ( features, "CPUID has no extended functions\n" );
return;
}
if ( max_level < CPUID_AMD_FEATURES ) {
DBGC ( features, "CPUID has no AMD-defined features (max "
"level %08x)\n", max_level );
return;
}
/* Get features */
cpuid ( CPUID_AMD_FEATURES, &discard_a, &discard_b,
&features->amd.ecx, &features->amd.edx );
DBGC ( features, "CPUID AMD features: %%ecx=%08x, %%edx=%08x\n",
features->amd.ecx, features->amd.edx );
}
/**
* Get x86 CPU features
*
* @v features x86 CPU features to fill in
*/
void x86_features ( struct x86_features *features ) {
/* Clear all features */
memset ( features, 0, sizeof ( *features ) );
/* Check that CPUID instruction is available */
if ( ! cpuid_is_supported() ) {
DBGC ( features, "CPUID instruction is not supported\n" );
return;
}
/* Get Intel-defined features */
x86_intel_features ( features );
/* Get AMD-defined features */
x86_amd_features ( features );
}
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