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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.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <string.h>
#include <errno.h>
#include <ipxe/cpuid.h>
/** @file
*
* x86 CPU feature detection
*
*/
/** Colour for debug messages */
#define colour 0x861d
/**
* Check whether or not CPUID instruction is supported
*
* @ret rc Return status code
*/
static int cpuid_instruction_supported ( void ) {
unsigned long original;
unsigned long inverted;
/* Check for instruction existence via flag modifiability */
__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 ) );
if ( ! ( ( original ^ inverted ) & CPUID_FLAG ) ) {
DBGC ( colour, "CPUID instruction is not supported\n" );
return -ENOTSUP;
}
return 0;
}
/**
* Check whether or not CPUID function is supported
*
* @v function CPUID function
* @ret rc Return status code
*/
int cpuid_supported ( uint32_t function ) {
uint32_t max_function;
uint32_t discard_b;
uint32_t discard_c;
uint32_t discard_d;
int rc;
/* Check that CPUID instruction is available */
if ( ( rc = cpuid_instruction_supported() ) != 0 )
return rc;
/* Find highest supported function number within this family */
cpuid ( ( function & CPUID_EXTENDED ), &max_function, &discard_b,
&discard_c, &discard_d );
/* Fail if maximum function number is meaningless (e.g. if we
* are attempting to call an extended function on a CPU which
* does not support them).
*/
if ( ( max_function & CPUID_AMD_CHECK_MASK ) !=
( function & CPUID_AMD_CHECK_MASK ) ) {
DBGC ( colour, "CPUID invalid maximum function %#08x\n",
max_function );
return -EINVAL;
}
/* Fail if this function is not supported */
if ( function > max_function ) {
DBGC ( colour, "CPUID function %#08x not supported\n",
function );
return -ENOTTY;
}
return 0;
}
/**
* 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 discard_a;
uint32_t discard_b;
int rc;
/* Check that features are available via CPUID */
if ( ( rc = cpuid_supported ( CPUID_FEATURES ) ) != 0 ) {
DBGC ( features, "CPUID has no Intel-defined features\n" );
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 discard_a;
uint32_t discard_b;
int rc;
/* Check that features are available via CPUID */
if ( ( rc = cpuid_supported ( CPUID_AMD_FEATURES ) ) != 0 ) {
DBGC ( features, "CPUID has no AMD-defined features\n" );
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 ) );
/* Get Intel-defined features */
x86_intel_features ( features );
/* Get AMD-defined features */
x86_amd_features ( features );
}
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