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/* SPDX-License-Identifier: GPL-2.0-only */
/* This file is part of the coreboot project. */
#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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