x86: introduce ldt_desc type.

this patch introduces ldt_desc type to account for the differences
in the ldt descriptor in x86_64 and i386

Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

include/asm-x86/desc_64.h

@@ -113,7 +113,7 @@ static inline void store_idt(struct desc_ptr *dtr)
 static inline void set_tssldt_descriptor(void *ptr, unsigned long tss,
 					 unsigned type, unsigned size)
 {
-	struct ldttss_desc d;
+	struct ldttss_desc64 d;
 
 	memset(&d, 0, sizeof(d));
 	d.limit0 = size & 0xFFFF;

include/asm-x86/desc_defs.h

@@ -58,7 +58,7 @@ enum {
 };
 
 // LDT or TSS descriptor in the GDT. 16 bytes.
-struct ldttss_desc {
+struct ldttss_desc64 {
 	u16 limit0;
 	u16 base0;
 	unsigned base1 : 8, type : 5, dpl : 2, p : 1;
@@ -69,8 +69,10 @@ struct ldttss_desc {
 
 #ifdef CONFIG_X86_64
 typedef struct gate_struct64 gate_desc;
+typedef struct ldttss_desc64 ldt_desc;
 #else
 typedef struct desc_struct gate_desc;
+typedef struct desc_struct ldt_desc;
 #endif
 
 struct desc_ptr {