-#define KERNEL64_CS 0x80 /* kernel 64-bit code */
-#define KERNEL64_SS 0x88 /* kernel 64-bit (syscall) stack */
+/*
+ * Kernel descriptors for MACH - 64-bit flat address space.
+ */
+#define KERNEL64_CS 0x08 /* 1: K64 code */
+#define SYSENTER_CS 0x0b /* U32 sysenter pseudo-segment */
+#define KERNEL64_SS 0x10 /* 2: KERNEL64_CS+8 for syscall */
+#define USER_CS 0x1b /* 3: U32 code */
+#define USER_DS 0x23 /* 4: USER_CS+8 for sysret */
+#define USER64_CS 0x2b /* 5: USER_CS+16 for sysret */
+#define USER64_DS USER_DS /* U64 data pseudo-segment */
+#define KERNEL_LDT 0x30 /* 6: */
+ /* 7: other 8 bytes of KERNEL_LDT */
+#define KERNEL_TSS 0x40 /* 8: */
+ /* 9: other 8 bytes of KERNEL_TSS */
+#define KERNEL32_CS 0x50 /* 10: */
+#define USER_LDT 0x58 /* 11: */
+ /* 12: other 8 bytes of USER_LDT */
+#define KERNEL_DS 0x68 /* 13: 32-bit kernel data */