x86: segment selector macros

This copies into asm-x86/segment_64.h some macros from asm-x86/segment_32.h
for dissecting segment selectors.  This lets other code use these macros
uniformly on 32/64-bit rather than duplicating the constants elsewhere.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/asm-x86/segment_64.h b/include/asm-x86/segment_64.h
index 04b8ab21328f..dce742101348 100644
--- a/include/asm-x86/segment_64.h
+++ b/include/asm-x86/segment_64.h
@@ -50,4 +50,15 @@
 #define GDT_SIZE (GDT_ENTRIES * 8)
 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8) 
 
+/* Bottom two bits of selector give the ring privilege level */
+#define SEGMENT_RPL_MASK        0x3
+/* Bit 2 is table indicator (LDT/GDT) */
+#define SEGMENT_TI_MASK         0x4
+
+/* User mode is privilege level 3 */
+#define USER_RPL                0x3
+/* LDT segment has TI set, GDT has it cleared */
+#define SEGMENT_LDT             0x4
+#define SEGMENT_GDT             0x0
+
 #endif