4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> To support force disabling of SMT it's required to know the number of thread siblings early. detect_ht() cannot be called before the APIC driver is selected, so split out the part which initializes smp_num_siblings. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/cpu/common.c | 24 ++++++++++++++---------- arch/x86/kernel/cpu/cpu.h | 1 + 2 files changed, 15 insertions(+), 10 deletions(-) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -661,32 +661,36 @@ static void cpu_detect_tlb(struct cpuinf tlb_lld_4m[ENTRIES], tlb_lld_1g[ENTRIES]); } -void detect_ht(struct cpuinfo_x86 *c) +int detect_ht_early(struct cpuinfo_x86 *c) { #ifdef CONFIG_SMP u32 eax, ebx, ecx, edx; - int index_msb, core_bits; if (!cpu_has(c, X86_FEATURE_HT)) - return; + return -1; if (cpu_has(c, X86_FEATURE_CMP_LEGACY)) - return; + return -1; if (cpu_has(c, X86_FEATURE_XTOPOLOGY)) - return; + return -1; cpuid(1, &eax, &ebx, &ecx, &edx); smp_num_siblings = (ebx & 0xff0000) >> 16; + if (smp_num_siblings == 1) + pr_info_once("CPU0: Hyper-Threading is disabled\n"); +#endif + return 0; +} - if (!smp_num_siblings) - smp_num_siblings = 1; +void detect_ht(struct cpuinfo_x86 *c) +{ +#ifdef CONFIG_SMP + int index_msb, core_bits; - if (smp_num_siblings == 1) { - pr_info_once("CPU0: Hyper-Threading is disabled\n"); + if (detect_ht_early(c) < 0) return; - } index_msb = get_count_order(smp_num_siblings); c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, index_msb); --- a/arch/x86/kernel/cpu/cpu.h +++ b/arch/x86/kernel/cpu/cpu.h @@ -56,6 +56,7 @@ extern void init_amd_cacheinfo(struct cp extern void detect_num_cpu_cores(struct cpuinfo_x86 *c); extern int detect_extended_topology(struct cpuinfo_x86 *c); +extern int detect_ht_early(struct cpuinfo_x86 *c); extern void detect_ht(struct cpuinfo_x86 *c); unsigned int aperfmperf_get_khz(int cpu);