diff options
Diffstat (limited to 'arch/x86/kernel/apic/apic.c')
| -rw-r--r-- | arch/x86/kernel/apic/apic.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c index 07fa222f0c52..84132eddb5a8 100644 --- a/arch/x86/kernel/apic/apic.c +++ b/arch/x86/kernel/apic/apic.c @@ -56,6 +56,7 @@ #include <asm/hypervisor.h> #include <asm/cpu_device_id.h> #include <asm/intel-family.h> +#include <asm/irq_regs.h> unsigned int num_processors; @@ -2192,6 +2193,23 @@ static int cpuid_to_apicid[] = { [0 ... NR_CPUS - 1] = -1, }; +#ifdef CONFIG_SMP +/** + * apic_id_is_primary_thread - Check whether APIC ID belongs to a primary thread + * @id: APIC ID to check + */ +bool apic_id_is_primary_thread(unsigned int apicid) +{ + u32 mask; + + if (smp_num_siblings == 1) + return true; + /* Isolate the SMT bit(s) in the APICID and check for 0 */ + mask = (1U << (fls(smp_num_siblings) - 1)) - 1; + return !(apicid & mask); +} +#endif + /* * Should use this API to allocate logical CPU IDs to keep nr_logical_cpuids * and cpuid_to_apicid[] synchronized. |