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Diffstat (limited to 'src/cpu/intel/common/hyperthreading.c')
-rw-r--r-- | src/cpu/intel/common/hyperthreading.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/src/cpu/intel/common/hyperthreading.c b/src/cpu/intel/common/hyperthreading.c new file mode 100644 index 0000000000..4caf49e5b6 --- /dev/null +++ b/src/cpu/intel/common/hyperthreading.c @@ -0,0 +1,45 @@ +/* + * 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)); +} |