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/*
* This file is part of the coreboot project.
*
* 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; version 2 of the License.
*
* 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.
*/
#include <cpu/x86/lapic.h>
#include <cpu/intel/common/common.h>
#include <arch/cpu.h>
/*
* Return true if running thread does not have the smallest lapic ID
* within a CPU core.
*/
bool intel_ht_sibling(void)
{
struct cpuid_result result;
unsigned int core_ids, apic_ids, threads;
/* Is Hyper-Threading supported */
if (!(cpuid_edx(1) & CPUID_FEAURE_HTT))
return false;
apic_ids = 1;
if (cpuid_eax(0) >= 1)
apic_ids = (cpuid_ebx(1) >> 16) & 0xff;
if (apic_ids == 0)
apic_ids = 1;
core_ids = 1;
if (cpuid_eax(0) >= 4) {
result = cpuid_ext(4, 0);
core_ids += (result.eax >> 26) & 0x3f;
}
threads = (apic_ids / core_ids);
return !!(lapicid() & (threads - 1));
}
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