x86: Use get_desc_base()

Use get_desc_base() to get the base address in desc_struct

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <20090718150853.GA11294@localhost.localdomain>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/doublefault_32.c b/arch/x86/kernel/doublefault_32.c
index b4f14c6..37250fe 100644
--- a/arch/x86/kernel/doublefault_32.c
+++ b/arch/x86/kernel/doublefault_32.c
@@ -27,9 +27,7 @@
 
 	if (ptr_ok(gdt)) {
 		gdt += GDT_ENTRY_TSS << 3;
-		tss = *(u16 *)(gdt+2);
-		tss += *(u8 *)(gdt+4) << 16;
-		tss += *(u8 *)(gdt+7) << 24;
+		tss = get_desc_base((struct desc_struct *)gdt);
 		printk(KERN_EMERG "double fault, tss at %08lx\n", tss);
 
 		if (ptr_ok(tss)) {