| From foo@baz Tue Aug 14 16:14:56 CEST 2018 |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Wed, 6 Jun 2018 00:53:57 +0200 |
| Subject: x86/cpu/common: Provide detect_ht_early() |
| |
| From: Thomas Gleixner <tglx@linutronix.de> |
| |
| commit 545401f4448a807b963ff17b575e0a393e68b523 upstream |
| |
| 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@linutronix.de> |
| Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> |
| Acked-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| 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 |
| @@ -606,32 +606,36 @@ 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 |
| @@ -46,6 +46,7 @@ extern const struct cpu_dev *const __x86 |
| |
| extern void get_cpu_cap(struct cpuinfo_x86 *c); |
| extern void cpu_detect_cache_sizes(struct cpuinfo_x86 *c); |
| +extern int detect_ht_early(struct cpuinfo_x86 *c); |
| |
| extern void x86_spec_ctrl_setup_ap(void); |
| |