x86/topology: Provide topology_smt_supported()

KAGA-KOKO · KAGA-KOKO · commit f048c399e0f7 · 2018-06-21T14:20:57.000+02:00
Provide information whether SMT is supoorted by the CPUs. Preparatory patch
for SMT control mechanism.

Suggested-by: Dave Hansen &lt;dave.hansen@intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Acked-by: Ingo Molnar &lt;mingo@kernel.org&gt;
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
@@ -125,13 +125,15 @@ static inline int topology_max_smt_threads(void)
 int topology_update_package_map(unsigned int apicid, unsigned int cpu);
 int topology_phys_to_logical_pkg(unsigned int pkg);
 bool topology_is_primary_thread(unsigned int cpu);
+bool topology_smt_supported(void);
 #else
 #define topology_max_packages()			(1)
 static inline int
 topology_update_package_map(unsigned int apicid, unsigned int cpu) { return 0; }
 static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; }
 static inline int topology_max_smt_threads(void) { return 1; }
 static inline bool topology_is_primary_thread(unsigned int cpu) { return true; }
+static inline bool topology_smt_supported(void) { return false; }
 #endif
 
 static inline void arch_fix_phys_package_id(int num, u32 slot)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
@@ -274,6 +274,14 @@ bool topology_is_primary_thread(unsigned int cpu)
 	return apic_id_is_primary_thread(per_cpu(x86_cpu_to_apicid, cpu));
 }
 
+/**
+ * topology_smt_supported - Check whether SMT is supported by the CPUs
+ */
+bool topology_smt_supported(void)
+{
+	return smp_num_siblings > 1;
+}
+
 /**
  * topology_phys_to_logical_pkg - Map a physical package id to a logical
  *

Original file line number	Diff line number	Diff line change
`@@ -274,6 +274,14 @@ bool topology_is_primary_thread(unsigned int cpu)`
`274`	`274`	`return apic_id_is_primary_thread(per_cpu(x86_cpu_to_apicid, cpu));`
`275`	`275`	`}`
`276`	`276`
	`277`	`+/**`
	`278`	`+ * topology_smt_supported - Check whether SMT is supported by the CPUs`
	`279`	`+ */`
	`280`	`+bool topology_smt_supported(void)`
	`281`	`+{`
	`282`	`+ return smp_num_siblings > 1;`
	`283`	`+}`
	`284`	`+`
`277`	`285`	`/**`
`278`	`286`	`* topology_phys_to_logical_pkg - Map a physical package id to a logical`
`279`	`287`	`*`