| From foo@baz Tue Aug 14 16:14:56 CEST 2018 |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Wed, 6 Jun 2018 00:55:39 +0200 |
| Subject: x86/cpu/topology: Provide detect_extended_topology_early() |
| |
| From: Thomas Gleixner <tglx@linutronix.de> |
| |
| commit 95f3d39ccf7aaea79d1ffdac1c887c2e100ec1b6 upstream |
| |
| To support force disabling of SMT it's required to know the number of |
| thread siblings early. detect_extended_topology() 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/cpu.h | 1 + |
| arch/x86/kernel/cpu/topology.c | 30 ++++++++++++++++++++++++------ |
| 2 files changed, 25 insertions(+), 6 deletions(-) |
| |
| --- 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_extended_topology_early(struct cpuinfo_x86 *c); |
| extern int detect_ht_early(struct cpuinfo_x86 *c); |
| |
| extern void x86_spec_ctrl_setup_ap(void); |
| --- a/arch/x86/kernel/cpu/topology.c |
| +++ b/arch/x86/kernel/cpu/topology.c |
| @@ -26,15 +26,13 @@ |
| * exists, use it for populating initial_apicid and cpu topology |
| * detection. |
| */ |
| -void detect_extended_topology(struct cpuinfo_x86 *c) |
| +int detect_extended_topology_early(struct cpuinfo_x86 *c) |
| { |
| #ifdef CONFIG_SMP |
| - unsigned int eax, ebx, ecx, edx, sub_index; |
| - unsigned int ht_mask_width, core_plus_mask_width; |
| - unsigned int core_select_mask, core_level_siblings; |
| + unsigned int eax, ebx, ecx, edx; |
| |
| if (c->cpuid_level < 0xb) |
| - return; |
| + return -1; |
| |
| cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx); |
| |
| @@ -42,7 +40,7 @@ void detect_extended_topology(struct cpu |
| * check if the cpuid leaf 0xb is actually implemented. |
| */ |
| if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE)) |
| - return; |
| + return -1; |
| |
| set_cpu_cap(c, X86_FEATURE_XTOPOLOGY); |
| |
| @@ -50,10 +48,30 @@ void detect_extended_topology(struct cpu |
| * initial apic id, which also represents 32-bit extended x2apic id. |
| */ |
| c->initial_apicid = edx; |
| + smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); |
| +#endif |
| + return 0; |
| +} |
| + |
| +/* |
| + * Check for extended topology enumeration cpuid leaf 0xb and if it |
| + * exists, use it for populating initial_apicid and cpu topology |
| + * detection. |
| + */ |
| +void detect_extended_topology(struct cpuinfo_x86 *c) |
| +{ |
| +#ifdef CONFIG_SMP |
| + unsigned int eax, ebx, ecx, edx, sub_index; |
| + unsigned int ht_mask_width, core_plus_mask_width; |
| + unsigned int core_select_mask, core_level_siblings; |
| + |
| + if (detect_extended_topology_early(c) < 0) |
| + return; |
| |
| /* |
| * Populate HT related information from sub-leaf level 0. |
| */ |
| + cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx); |
| core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx); |
| core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax); |
| |