x86: add apic probe for genapic 64bit, v2

introducing an APIC handling probing abstraction:

 static struct genapic *apic_probe[] __initdata = {
	&apic_x2apic_uv_x,
	&apic_x2apic_phys,
	&apic_x2apic_cluster,
	&apic_physflat,
	NULL,
 };

This way we can remove UV, x2apic specific code from genapic_64.c and
move them to their specific genapic files.

[ v2: fix compiling when CONFIG_ACPI is not set ]

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/genapic_64.c b/arch/x86/kernel/genapic_64.c
index 3940d81..b3ba969 100644
--- a/arch/x86/kernel/genapic_64.c
+++ b/arch/x86/kernel/genapic_64.c
@@ -16,62 +16,37 @@
 #include <linux/ctype.h>
 #include <linux/init.h>
 #include <linux/hardirq.h>
-#include <linux/dmar.h>
 
 #include <asm/smp.h>
 #include <asm/ipi.h>
 #include <asm/genapic.h>
 
-#ifdef CONFIG_ACPI
-#include <acpi/acpi_bus.h>
-#endif
-
-DEFINE_PER_CPU(int, x2apic_extra_bits);
+extern struct genapic apic_flat;
+extern struct genapic apic_physflat;
+extern struct genapic apic_x2xpic_uv_x;
+extern struct genapic apic_x2apic_phys;
+extern struct genapic apic_x2apic_cluster;
 
 struct genapic __read_mostly *genapic = &apic_flat;
 
-static int x2apic_phys = 0;
-
-static int set_x2apic_phys_mode(char *arg)
-{
-	x2apic_phys = 1;
-	return 0;
-}
-early_param("x2apic_phys", set_x2apic_phys_mode);
-
-static enum uv_system_type uv_system_type;
+static struct genapic *apic_probe[] __initdata = {
+	&apic_x2apic_uv_x,
+	&apic_x2apic_phys,
+	&apic_x2apic_cluster,
+	&apic_physflat,
+	NULL,
+};
 
 /*
  * Check the APIC IDs in bios_cpu_apicid and choose the APIC mode.
  */
 void __init setup_apic_routing(void)
 {
-	if (uv_system_type == UV_NON_UNIQUE_APIC)
-		genapic = &apic_x2apic_uv_x;
-	else if (cpu_has_x2apic && intr_remapping_enabled) {
-		if (x2apic_phys)
-			genapic = &apic_x2apic_phys;
-		else
-			genapic = &apic_x2apic_cluster;
-	} else
-#ifdef CONFIG_ACPI
-	/*
-	 * Quirk: some x86_64 machines can only use physical APIC mode
-	 * regardless of how many processors are present (x86_64 ES7000
-	 * is an example).
-	 */
-	if (acpi_gbl_FADT.header.revision > FADT2_REVISION_ID &&
-			(acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL))
-		genapic = &apic_physflat;
-	else
-#endif
-
-	if (max_physical_apicid < 8)
-		genapic = &apic_flat;
-	else
-		genapic = &apic_physflat;
-
-	printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
+	if (genapic == &apic_flat) {
+		if (max_physical_apicid >= 8)
+			genapic = &apic_physflat;
+		printk(KERN_INFO "Setting APIC routing to %s\n", genapic->name);
+	}
 }
 
 /* Same for both flat and physical. */
@@ -83,23 +58,15 @@
 
 int __init acpi_madt_oem_check(char *oem_id, char *oem_table_id)
 {
-	if (!strcmp(oem_id, "SGI")) {
-		if (!strcmp(oem_table_id, "UVL"))
-			uv_system_type = UV_LEGACY_APIC;
-		else if (!strcmp(oem_table_id, "UVX"))
-			uv_system_type = UV_X2APIC;
-		else if (!strcmp(oem_table_id, "UVH"))
-			uv_system_type = UV_NON_UNIQUE_APIC;
+	int i;
+
+	for (i = 0; apic_probe[i]; ++i) {
+		if (apic_probe[i]->acpi_madt_oem_check(oem_id, oem_table_id)) {
+			genapic = apic_probe[i];
+			printk(KERN_INFO "Setting APIC routing to %s.\n",
+				genapic->name);
+			return 1;
+		}
 	}
 	return 0;
 }
-
-enum uv_system_type get_uv_system_type(void)
-{
-	return uv_system_type;
-}
-
-int is_uv_system(void)
-{
-	return uv_system_type != UV_NONE;
-}