/* SPDX-License-Identifier: GPL-2.0-only */ #include <cpu/cpu.h> #include <cpu/intel/common/common.h> #include <types.h> bool intel_ht_supported(void) { /* Is HyperThreading supported? */ return !!(cpuid_edx(1) & CPUID_FEATURE_HTT); } /* * 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; unsigned int max_leaf; uint32_t initial_lapicid, threads; if (!intel_ht_supported()) return false; max_leaf = cpuid_get_max_func(); /* Detect from 32-bit X2APIC ID. */ if (max_leaf >= 0xb) { result = cpuid_ext(0xb, 0); threads = 1 << (result.eax & 0x1f); initial_lapicid = result.edx; return initial_lapicid % threads > 0; } /* Detect from 8-bit XAPIC ID. */ result = cpuid_ext(0x1, 0); initial_lapicid = result.ebx >> 24; apic_ids = (result.ebx >> 16) & 0xff; if (apic_ids == 0) apic_ids = 1; core_ids = 1; if (max_leaf >= 4) { result = cpuid_ext(4, 0); core_ids += (result.eax >> 26) & 0x3f; } threads = (apic_ids / core_ids); return initial_lapicid % threads > 0; }