x86: use descriptor's functions instead of inline assembly

This patch provides a new set of functions for managing the descriptor
tables that can be used instead of putting the raw assembly in .c files.

Remodeling of store_tr() suggested by Frederik Deweerdt.

[ tglx: arch/x86 adaptation ]

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index a7eee0a..6b34693 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -58,7 +58,7 @@
 
 	for (i = 0; i < IDT_ENTRIES; i++)
 		set_intr_gate(i, early_idt_handler);
-	asm volatile("lidt %0" :: "m" (idt_descr));
+	load_idt((const struct desc_ptr *)&idt_descr);
 
 	early_printk("Kernel alive\n");