cpu/SMT: Remove topology_smt_supported()

Since the maximum number of threads is now passed to cpu_smt_set_num_threads(),
checking that value is enough to know whether SMT is supported.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20230705145143.40545-6-ldufour@linux.ibm.com

Author: ldu4

arch/x86/include/asm/topology.h

@@ -141,7 +141,6 @@ static inline int topology_max_smt_threads(void)
 int topology_update_package_map(unsigned int apicid, unsigned int cpu);
 int topology_update_die_map(unsigned int dieid, unsigned int cpu);
 int topology_phys_to_logical_pkg(unsigned int pkg);
-bool topology_smt_supported(void);
 
 extern struct cpumask __cpu_primary_thread_mask;
 #define cpu_primary_thread_mask ((const struct cpumask *)&__cpu_primary_thread_mask)
@@ -164,7 +163,6 @@ static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; }
 static inline int topology_max_die_per_package(void) { return 1; }
 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 /* !CONFIG_SMP */
 
 static inline void arch_fix_phys_package_id(int num, u32 slot)

arch/x86/kernel/smpboot.c

@@ -326,14 +326,6 @@ static void notrace start_secondary(void *unused)
 	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 }
 
-/**
- * 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
  * @phys_pkg:	The physical package id to map

kernel/cpu.c

@@ -621,7 +621,7 @@ void __init cpu_smt_set_num_threads(unsigned int num_threads,
 {
 	WARN_ON(!num_threads || (num_threads > max_threads));
 
-	if (!topology_smt_supported())
+	if (max_threads == 1)
 		cpu_smt_control = CPU_SMT_NOT_SUPPORTED;
 
 	cpu_smt_max_threads = max_threads;
@@ -1801,7 +1801,7 @@ early_param("cpuhp.parallel", parallel_bringup_parse_param);
 
 static inline bool cpuhp_smt_aware(void)
 {
-	return topology_smt_supported();
+	return cpu_smt_max_threads > 1;
 }
 
 static inline const struct cpumask *cpuhp_get_primary_thread_mask(void)