4.17-stable review patch. If anyone has any objections, please let me know.
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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: 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 @@ -47,6 +47,7 @@ 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);
unsigned int aperfmperf_get_khz(int cpu); --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -27,15 +27,13 @@ * 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);
@@ -43,7 +41,7 @@ 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);
@@ -51,10 +49,30 @@ 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);