X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=arch%2Fx86_64%2Fkernel%2Fgenapic.c;h=7a64ea181788c62e3c6a8e9e07a378ffa0a23ac0;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=69b9c25a8fc4ee5399b76b4a5d0967fc9c520f33;hpb=cee37fe97739d85991964371c1f3a745c00dd236;p=linux-2.6.git

diff --git a/arch/x86_64/kernel/genapic.c b/arch/x86_64/kernel/genapic.c
index 69b9c25a8..7a64ea181 100644
--- a/arch/x86_64/kernel/genapic.c
+++ b/arch/x86_64/kernel/genapic.c
@@ -20,17 +20,18 @@
 #include <asm/smp.h>
 #include <asm/ipi.h>
 
-#if defined(CONFIG_ACPI_BUS)
+#if defined(CONFIG_ACPI)
 #include <acpi/acpi_bus.h>
 #endif
 
 /* which logical CPU number maps to which CPU (physical APIC ID) */
-u8 x86_cpu_to_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
+u8 x86_cpu_to_apicid[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = BAD_APICID };
 EXPORT_SYMBOL(x86_cpu_to_apicid);
 u8 x86_cpu_to_log_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
 
 extern struct genapic apic_cluster;
 extern struct genapic apic_flat;
+extern struct genapic apic_physflat;
 
 struct genapic *genapic = &apic_flat;
 
@@ -44,14 +45,9 @@ void __init clustered_apic_check(void)
 	u8 clusters, max_cluster;
 	u8 id;
 	u8 cluster_cnt[NUM_APIC_CLUSTERS];
+	int max_apic = 0;
 
-	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
-		/* AMD always uses flat mode right now */
-		genapic = &apic_flat;
-		goto print;
-	}
-
-#if defined(CONFIG_ACPI_BUS)
+#if defined(CONFIG_ACPI)
 	/*
 	 * Some x86_64 machines use physical APIC mode regardless of how many
 	 * procs/clusters are present (x86_64 ES7000 is an example).
@@ -64,15 +60,35 @@ void __init clustered_apic_check(void)
 #endif
 
 	memset(cluster_cnt, 0, sizeof(cluster_cnt));
-
 	for (i = 0; i < NR_CPUS; i++) {
 		id = bios_cpu_apicid[i];
-		if (id != BAD_APICID)
-			cluster_cnt[APIC_CLUSTERID(id)]++;
+		if (id == BAD_APICID)
+			continue;
+		if (id > max_apic)
+			max_apic = id;
+		cluster_cnt[APIC_CLUSTERID(id)]++;
 	}
 
+	/* Don't use clustered mode on AMD platforms. */
+ 	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
+ 		goto print;
+ 	}
+
 	clusters = 0;
 	max_cluster = 0;
+
 	for (i = 0; i < NUM_APIC_CLUSTERS; i++) {
 		if (cluster_cnt[i] > 0) {
 			++clusters;
@@ -88,9 +104,14 @@ 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)
+	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
 		genapic = &apic_flat;
-	else
+#endif
+	} else
 		genapic = &apic_cluster;
 
 print: