156 lines
4.0 KiB
C
156 lines
4.0 KiB
C
/*
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* Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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#include <string.h>
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#include <ipxe/cpuid.h>
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/** @file
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*
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* x86 CPU feature detection
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*
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*/
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/**
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* Check whether or not CPUID instruction is supported
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*
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* @ret is_supported CPUID instruction is supported
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*/
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static int cpuid_is_supported ( void ) {
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unsigned long original;
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unsigned long inverted;
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__asm__ ( "pushf\n\t"
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"pushf\n\t"
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"pop %0\n\t"
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"mov %0,%1\n\t"
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"xor %2,%1\n\t"
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"push %1\n\t"
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"popf\n\t"
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"pushf\n\t"
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"pop %1\n\t"
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"popf\n\t"
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: "=&r" ( original ), "=&r" ( inverted )
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: "ir" ( CPUID_FLAG ) );
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return ( ( original ^ inverted ) & CPUID_FLAG );
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}
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/**
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* Issue CPUID instruction
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*
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* @v operation CPUID operation
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* @v eax Output via %eax
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* @v ebx Output via %ebx
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* @v ecx Output via %ecx
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* @v edx Output via %edx
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*/
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static inline __attribute__ (( always_inline )) void
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cpuid ( uint32_t operation, uint32_t *eax, uint32_t *ebx, uint32_t *ecx,
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uint32_t *edx ) {
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__asm__ ( "cpuid"
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: "=a" ( *eax ), "=b" ( *ebx ), "=c" ( *ecx ), "=d" ( *edx )
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: "0" ( operation ) );
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}
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/**
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* Get Intel-defined x86 CPU features
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*
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* @v features x86 CPU features to fill in
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*/
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static void x86_intel_features ( struct x86_features *features ) {
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uint32_t max_level;
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uint32_t discard_a;
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uint32_t discard_b;
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uint32_t discard_c;
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uint32_t discard_d;
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/* Check that features are available via CPUID */
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cpuid ( CPUID_VENDOR_ID, &max_level, &discard_b, &discard_c,
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&discard_d );
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if ( max_level < CPUID_FEATURES ) {
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DBGC ( features, "CPUID has no Intel-defined features (max "
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"level %08x)\n", max_level );
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return;
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}
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/* Get features */
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cpuid ( CPUID_FEATURES, &discard_a, &discard_b,
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&features->intel.ecx, &features->intel.edx );
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DBGC ( features, "CPUID Intel features: %%ecx=%08x, %%edx=%08x\n",
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features->intel.ecx, features->intel.edx );
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}
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/**
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* Get AMD-defined x86 CPU features
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*
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* @v features x86 CPU features to fill in
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*/
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static void x86_amd_features ( struct x86_features *features ) {
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uint32_t max_level;
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uint32_t discard_a;
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uint32_t discard_b;
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uint32_t discard_c;
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uint32_t discard_d;
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/* Check that features are available via CPUID */
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cpuid ( CPUID_AMD_MAX_FN, &max_level, &discard_b, &discard_c,
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&discard_d );
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if ( ( max_level & CPUID_AMD_CHECK_MASK ) != CPUID_AMD_CHECK ) {
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DBGC ( features, "CPUID has no extended functions\n" );
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return;
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}
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if ( max_level < CPUID_AMD_FEATURES ) {
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DBGC ( features, "CPUID has no AMD-defined features (max "
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"level %08x)\n", max_level );
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return;
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}
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/* Get features */
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cpuid ( CPUID_AMD_FEATURES, &discard_a, &discard_b,
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&features->amd.ecx, &features->amd.edx );
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DBGC ( features, "CPUID AMD features: %%ecx=%08x, %%edx=%08x\n",
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features->amd.ecx, features->amd.edx );
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}
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/**
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* Get x86 CPU features
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*
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* @v features x86 CPU features to fill in
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*/
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void x86_features ( struct x86_features *features ) {
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/* Clear all features */
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memset ( features, 0, sizeof ( *features ) );
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/* Check that CPUID instruction is available */
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if ( ! cpuid_is_supported() ) {
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DBGC ( features, "CPUID instruction is not supported\n" );
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return;
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}
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/* Get Intel-defined features */
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x86_intel_features ( features );
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/* Get AMD-defined features */
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x86_amd_features ( features );
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}
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