x86: Port x86 over to compile cleanly with x86-64

Change-Id: I26f1bbf027435be593f11bce4780111dcaf7cb86
Signed-off-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Signed-off-by: Scott Duplichan <scott@notabs.org>
Reviewed-on: http://review.coreboot.org/10586
Tested-by: build bot (Jenkins)
Tested-by: Raptor Engineering Automated Test Stand <noreply@raptorengineeringinc.com>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/src/arch/x86/boot/gdt.c b/src/arch/x86/boot/gdt.c
index 44156ea..a21fab2 100644
--- a/src/arch/x86/boot/gdt.c
+++ b/src/arch/x86/boot/gdt.c
@@ -26,7 +26,11 @@
 /* i386 lgdt argument */
 struct gdtarg {
 	u16 limit;
+#ifdef __x86_64__
+	u64 base;
+#else
 	u32 base;
+#endif
 } __attribute__((packed));
 
 /* Copy GDT to new location and reload it.
@@ -35,7 +39,7 @@
 static void move_gdt(int is_recovery)
 {
 	void *newgdt;
-	u16 num_gdt_bytes = (u32)&gdt_end - (u32)&gdt;
+	u16 num_gdt_bytes = (uintptr_t)&gdt_end - (uintptr_t)&gdt;
 	struct gdtarg gdtarg;
 
 	newgdt = cbmem_find(CBMEM_ID_GDT);
@@ -49,7 +53,7 @@
 		memcpy((void*)newgdt, &gdt, num_gdt_bytes);
 	}
 
-	gdtarg.base = (u32)newgdt;
+	gdtarg.base = (uintptr_t)newgdt;
 	gdtarg.limit = num_gdt_bytes - 1;
 
 	__asm__ __volatile__ ("lgdt %0\n\t" : : "m" (gdtarg));