1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 3 #include <cpu/cpu.h> 4 #include <cpu/intel/common/common.h> 5 #include <types.h> 6 intel_ht_supported(void)7bool intel_ht_supported(void) 8 { 9 /* Is HyperThreading supported? */ 10 return !!(cpuid_edx(1) & CPUID_FEATURE_HTT); 11 } 12 13 /* 14 * Return true if running thread does not have the smallest lapic ID 15 * within a CPU core. 16 */ intel_ht_sibling(void)17bool intel_ht_sibling(void) 18 { 19 struct cpuid_result result; 20 unsigned int core_ids, apic_ids; 21 unsigned int max_leaf; 22 uint32_t initial_lapicid, threads; 23 24 if (!intel_ht_supported()) 25 return false; 26 27 max_leaf = cpuid_get_max_func(); 28 29 /* Detect from 32-bit X2APIC ID. */ 30 if (max_leaf >= 0xb) { 31 result = cpuid_ext(0xb, 0); 32 threads = 1 << (result.eax & 0x1f); 33 initial_lapicid = result.edx; 34 return initial_lapicid % threads > 0; 35 } 36 37 /* Detect from 8-bit XAPIC ID. */ 38 result = cpuid_ext(0x1, 0); 39 initial_lapicid = result.ebx >> 24; 40 apic_ids = (result.ebx >> 16) & 0xff; 41 if (apic_ids == 0) 42 apic_ids = 1; 43 44 core_ids = 1; 45 if (max_leaf >= 4) { 46 result = cpuid_ext(4, 0); 47 core_ids += (result.eax >> 26) & 0x3f; 48 } 49 50 threads = (apic_ids / core_ids); 51 return initial_lapicid % threads > 0; 52 } 53