[PATCH] x86: fix broken SMP boot sequence

Recent GDT changes broke the SMP boot sequence if the booting CPU is
numbered anything other than zero.  There's also a subtle source of error
in that the boot time CPU now uses cpu_gdt_table (which is actually the GDT
for booting CPUs in head.S).  This patch fixes both problems by making GDT
descriptors themselves allocated from a per_cpu area and switching to them
in cpu_init(), which now means that cpu_gdt_table is exclusively used for
booting CPUs again.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Cc: Zachary Amsden <zach@vmware.com>
Cc: Matt Tolentino <metolent@snoqualmie.dp.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/efi.c b/arch/i386/kernel/efi.c
index ecad519..e3e42fd 100644
--- a/arch/i386/kernel/efi.c
+++ b/arch/i386/kernel/efi.c
@@ -103,17 +103,19 @@
 	 */
 	local_flush_tlb();
 
-	cpu_gdt_descr[0].address = __pa(cpu_gdt_descr[0].address);
-	load_gdt((struct Xgt_desc_struct *) __pa(&cpu_gdt_descr[0]));
+	per_cpu(cpu_gdt_descr, 0).address =
+				 __pa(per_cpu(cpu_gdt_descr, 0).address);
+	load_gdt((struct Xgt_desc_struct *)__pa(&per_cpu(cpu_gdt_descr, 0)));
 }
 
 static void efi_call_phys_epilog(void)
 {
 	unsigned long cr4;
 
-	cpu_gdt_descr[0].address =
-		(unsigned long) __va(cpu_gdt_descr[0].address);
-	load_gdt(&cpu_gdt_descr[0]);
+	per_cpu(cpu_gdt_descr, 0).address =
+			(unsigned long)__va(per_cpu(cpu_gdt_descr, 0).address);
+	load_gdt((struct Xgt_desc_struct *)__va(&per_cpu(cpu_gdt_descr, 0)));
+
 	cr4 = read_cr4();
 
 	if (cr4 & X86_CR4_PSE) {