diff options
Diffstat (limited to 'src/cpu/intel/hyperthreading')
| -rw-r--r-- | src/cpu/intel/hyperthreading/intel_sibling.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/src/cpu/intel/hyperthreading/intel_sibling.c b/src/cpu/intel/hyperthreading/intel_sibling.c index 2d2e105f8d..b9a9ae7bb1 100644 --- a/src/cpu/intel/hyperthreading/intel_sibling.c +++ b/src/cpu/intel/hyperthreading/intel_sibling.c @@ -14,6 +14,27 @@ static int first_time = 1; static int disable_siblings = !CONFIG_LOGICAL_CPUS; +/* Return true if running thread does not have the smallest lapic ID + * within a CPU core. + */ +int intel_ht_sibling(void) +{ + unsigned int core_ids, apic_ids, threads; + + apic_ids = 1; + if (cpuid_eax(0) >= 1) + apic_ids = (cpuid_ebx(1) >> 16) & 0xff; + if (apic_ids < 1) + apic_ids = 1; + + core_ids = 1; + if (cpuid_eax(0) >= 4) + core_ids += (cpuid_eax(4) >> 26) & 0x3f; + + threads = (apic_ids / core_ids); + return !!(lapicid() & (threads-1)); +} + void intel_sibling_init(device_t cpu) { unsigned i, siblings; |