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-rw-r--r--arch/powerpc/include/asm/topology.h1
-rw-r--r--arch/x86/include/asm/topology.h2
-rw-r--r--include/linux/topology.h23
3 files changed, 25 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index 16bacfe8c7a2..da15b5efe807 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -152,6 +152,7 @@ static inline bool topology_is_primary_thread(unsigned int cpu)
{
return cpu == cpu_first_thread_sibling(cpu);
}
+#define topology_is_primary_thread topology_is_primary_thread
static inline bool topology_smt_thread_allowed(unsigned int cpu)
{
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index ec134b719144..6c79ee7c0957 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -229,11 +229,11 @@ static inline bool topology_is_primary_thread(unsigned int cpu)
{
return cpumask_test_cpu(cpu, cpu_primary_thread_mask);
}
+#define topology_is_primary_thread topology_is_primary_thread
#else /* CONFIG_SMP */
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 unsigned int topology_amd_nodes_per_pkg(void) { return 1; }
#endif /* !CONFIG_SMP */
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 52f5850730b3..f8bb02c5e8a4 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -240,6 +240,29 @@ static inline const struct cpumask *cpu_smt_mask(int cpu)
}
#endif
+#ifndef topology_is_primary_thread
+
+static inline bool topology_is_primary_thread(unsigned int cpu)
+{
+ /*
+ * When disabling SMT, the primary thread of the SMT will remain
+ * enabled/active. Architectures that have a special primary thread
+ * (e.g. x86) need to override this function. Otherwise the first
+ * thread in the SMT can be made the primary thread.
+ *
+ * The sibling cpumask of an offline CPU always contains the CPU
+ * itself on architectures using the implementation of
+ * CONFIG_GENERIC_ARCH_TOPOLOGY for building their topology.
+ * Other architectures not using CONFIG_GENERIC_ARCH_TOPOLOGY for
+ * building their topology have to check whether to use this default
+ * implementation or to override it.
+ */
+ return cpu == cpumask_first(topology_sibling_cpumask(cpu));
+}
+#define topology_is_primary_thread topology_is_primary_thread
+
+#endif
+
static inline const struct cpumask *cpu_cpu_mask(int cpu)
{
return cpumask_of_node(cpu_to_node(cpu));