diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2018-05-29 17:50:22 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-08-15 18:14:45 +0200 |
commit | 7b69a96e5a328f17fe33f3826d7e8349ab59015d (patch) | |
tree | a8f09be1ff2ed4561a1511e4efa7de3183e26568 /arch/x86/include | |
parent | 1ac1dc14671f531134f29755f98386f8e168b810 (diff) |
x86/smp: Provide topology_is_primary_thread()
commit 6a4d2657e048f096c7ffcad254010bd94891c8c0 upstream
If the CPU is supporting SMT then the primary thread can be found by
checking the lower APIC ID bits for zero. smp_num_siblings is used to build
the mask for the APIC ID bits which need to be taken into account.
This uses the MPTABLE or ACPI/MADT supplied APIC ID, which can be different
than the initial APIC ID in CPUID. But according to AMD the lower bits have
to be consistent. Intel gave a tentative confirmation as well.
Preparatory patch to support disabling SMT at boot/runtime.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
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>
Diffstat (limited to 'arch/x86/include')
-rw-r--r-- | arch/x86/include/asm/apic.h | 7 | ||||
-rw-r--r-- | arch/x86/include/asm/topology.h | 4 |
2 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h index f5aaf6c83222..20eed46c5827 100644 --- a/arch/x86/include/asm/apic.h +++ b/arch/x86/include/asm/apic.h @@ -633,6 +633,13 @@ extern int default_check_phys_apicid_present(int phys_apicid); #endif #endif /* CONFIG_X86_LOCAL_APIC */ + +#ifdef CONFIG_SMP +bool apic_id_is_primary_thread(unsigned int id); +#else +static inline bool apic_id_is_primary_thread(unsigned int id) { return false; } +#endif + extern void irq_enter(void); extern void irq_exit(void); diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index cf75871d2f81..e5e6c02c203f 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -129,13 +129,15 @@ static inline int topology_max_smt_threads(void) } int topology_update_package_map(unsigned int apicid, unsigned int cpu); -extern int topology_phys_to_logical_pkg(unsigned int pkg); +int topology_phys_to_logical_pkg(unsigned int pkg); +bool topology_is_primary_thread(unsigned int cpu); #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; } #endif static inline void arch_fix_phys_package_id(int num, u32 slot) |