diff options
Diffstat (limited to 'arch/x86_64/kernel/genapic.c')
| -rw-r--r-- | arch/x86_64/kernel/genapic.c | 39 |
1 files changed, 15 insertions, 24 deletions
diff --git a/arch/x86_64/kernel/genapic.c b/arch/x86_64/kernel/genapic.c index 7312ddb84fb..2f2b8fc6e2f 100644 --- a/arch/x86_64/kernel/genapic.c +++ b/arch/x86_64/kernel/genapic.c @@ -32,21 +32,20 @@ extern struct genapic apic_cluster; extern struct genapic apic_flat; extern struct genapic apic_physflat; -struct genapic *genapic = &apic_flat; - +struct genapic __read_mostly *genapic = &apic_flat; /* * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode. */ void __init clustered_apic_check(void) { - long i; + int i; u8 clusters, max_cluster; u8 id; u8 cluster_cnt[NUM_APIC_CLUSTERS]; int max_apic = 0; -#if defined(CONFIG_ACPI) +#ifdef CONFIG_ACPI /* * Some x86_64 machines use physical APIC mode regardless of how many * procs/clusters are present (x86_64 ES7000 is an example). @@ -68,20 +67,17 @@ void __init clustered_apic_check(void) cluster_cnt[APIC_CLUSTERID(id)]++; } - /* Don't use clustered mode on AMD platforms. */ + /* + * Don't use clustered mode on AMD platforms, default + * to flat logical mode. + */ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) { - genapic = &apic_physflat; -#ifndef CONFIG_HOTPLUG_CPU - /* In the CPU hotplug case we cannot use broadcast mode - because that opens a race when a CPU is removed. - Stay at physflat mode in this case. - It is bad to do this unconditionally though. Once - we have ACPI platform support for CPU hotplug - we should detect hotplug capablity from ACPI tables and - only do this when really needed. -AK */ - if (max_apic <= 8) - genapic = &apic_flat; -#endif + /* + * Switch to physical flat mode if more than 8 APICs + * (In the case of 8 CPUs APIC ID goes from 0 to 7): + */ + if (max_apic >= 8) + genapic = &apic_physflat; goto print; } @@ -103,14 +99,9 @@ void __init clustered_apic_check(void) * (We don't use lowest priority delivery + HW APIC IRQ steering, so * can ignore the clustered logical case and go straight to physical.) */ - if (clusters <= 1 && max_cluster <= 8 && cluster_cnt[0] == max_cluster) { -#ifdef CONFIG_HOTPLUG_CPU - /* Don't use APIC shortcuts in CPU hotplug to avoid races */ - genapic = &apic_physflat; -#else + if (clusters <= 1 && max_cluster <= 8 && cluster_cnt[0] == max_cluster) genapic = &apic_flat; -#endif - } else + else genapic = &apic_cluster; print: |