From f048c399e0f7490ab7296bc2c255d37eb14a9675 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 21 Jun 2018 10:37:20 +0200 Subject: [PATCH] x86/topology: Provide topology_smt_supported() Provide information whether SMT is supoorted by the CPUs. Preparatory patch for SMT control mechanism. Suggested-by: Dave Hansen Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar --- arch/x86/include/asm/topology.h | 2 ++ arch/x86/kernel/smpboot.c | 8 ++++++++ 2 files changed, 10 insertions(+) diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index 661e361a12a6..453cf38a1c33 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -125,6 +125,7 @@ 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 @@ -132,6 +133,7 @@ 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 index f9c731240142..7f7def989fb0 100644 --- 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 *