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authorThomas Gleixner <tglx@linutronix.de>2018-06-21 10:37:20 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-08-15 18:14:45 +0200
commit16fd33cd353be2cb71f2431788e5b2ae02891a77 (patch)
tree012923e5ddfb1330902f973b38d6a6c55aabaab9
parent7b69a96e5a328f17fe33f3826d7e8349ab59015d (diff)
x86/topology: Provide topology_smt_supported()
commit f048c399e0f7490ab7296bc2c255d37eb14a9675 upstream Provide information whether SMT is supoorted by the CPUs. Preparatory patch for SMT control mechanism. Suggested-by: Dave Hansen <dave.hansen@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/include/asm/topology.h2
-rw-r--r--arch/x86/kernel/smpboot.c8
2 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index e5e6c02c203f..1fbb174c846b 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -131,6 +131,7 @@ 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
@@ -138,6 +139,7 @@ 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 e230c47c88e3..168cc3baadf6 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -305,6 +305,14 @@ bool topology_is_primary_thread(unsigned int 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
*
* Returns logical package id or -1 if not found