x86, pci: introduce pci=ioapicreroute kernel cmdline option

Introduce pci=ioapicreroute kernel cmdline option to enable rerouting of boot
interrupts to the primary io-apic.

Signed-off-by: Stefan Assmann <sassmann@suse.de>
Signed-off-by: Olaf Dabrunz <od@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
index bc6a101..0a9eaa7 100644
--- a/arch/x86/pci/common.c
+++ b/arch/x86/pci/common.c
@@ -23,6 +23,7 @@
 static int pci_bf_sort;
 int pci_routeirq;
 int noioapicquirk;
+int noioapicreroute = 1;
 int pcibios_last_bus = -1;
 unsigned long pirq_table_addr;
 struct pci_bus *pci_root_bus;
@@ -499,6 +500,10 @@
 	} else if (!strcmp(str, "noioapicquirk")) {
 		noioapicquirk = 1;
 		return NULL;
+	} else if (!strcmp(str, "ioapicreroute")) {
+		if (noioapicreroute != -1)
+			noioapicreroute = 0;
+		return NULL;
 	}
 	return str;
 }