FLAT_RING3_SS64    25 arch/x86/include/asm/xen/interface_64.h #define FLAT_KERNEL_SS64 FLAT_RING3_SS64
FLAT_RING3_SS64    35 arch/x86/include/asm/xen/interface_64.h #define FLAT_USER_SS64 FLAT_RING3_SS64