The early detection stores the extended topology leaf number which is required for parallel hotplug. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> --- arch/x86/kernel/cpu/amd.c | 2 ++ 1 file changed, 2 insertions(+) --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -692,6 +692,8 @@ static void early_init_amd(struct cpuinf } } + detect_extended_topology_early(c); + if (cpu_has(c, X86_FEATURE_TOPOEXT)) smp_num_siblings = ((cpuid_ebx(0x8000001e) >> 8) & 0xff) + 1; }