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-rw-r--r--arch/x86_64/kernel/genapic.c39
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: