Index: 2006-01-05/arch/x86_64/kernel/head-xen.S
===================================================================
--- 2006-01-05.orig/arch/x86_64/kernel/head-xen.S	2006-01-09 16:17:27.588367840 +0100
+++ 2006-01-05/arch/x86_64/kernel/head-xen.S	2006-01-09 12:23:00.000000000 +0100
@@ -191,18 +191,18 @@ ENTRY(cpu_gdt_table)
 /* The TLS descriptors are currently at a different place compared to i386.
    Hopefully nobody expects them at a fixed place (Wine?) */
 	.quad	0x0000000000000000	/* NULL descriptor */
-	.quad	0x008ffa000000ffff	/* __KERNEL_COMPAT32_CS */	
+	.quad	0			/* unused, was __KERNEL_COMPAT32_CS */
 	.quad	0x00affa000000ffff	/* __KERNEL_CS */
 	.quad	0x00cff2000000ffff	/* __KERNEL_DS */
 	
        	.quad	0x00cffa000000ffff	/* __USER32_CS */
 	.quad	0x00cff2000000ffff	/* __USER_DS, __USER32_DS  */		
 	.quad	0x00affa000000ffff	/* __USER_CS */
-	.quad	0x00cffa000000ffff	/* __KERNEL32_CS */        
+	.quad	0			/* unused, was __KERNEL32_CS */
 	.quad	0,0			/* TSS */
 	.quad	0,0			/* LDT */
 	.quad   0,0,0			/* three TLS descriptors */ 
-	.quad	0			/* unused now?   __KERNEL16_CS - 16bit PM for S3 wakeup. */
+	.quad	0			/* unused, was __KERNEL16_CS - 16bit PM for S3 wakeup. */
 
 gdt_end:
 #if 0
Index: 2006-01-05/include/asm-x86_64/mach-xen/asm/segment.h
===================================================================
--- 2006-01-05.orig/include/asm-x86_64/mach-xen/asm/segment.h	2006-01-09 16:17:27.589367688 +0100
+++ /dev/null	1970-01-01 00:00:00.000000000 +0000
@@ -1,46 +0,0 @@
-#ifndef _ASM_SEGMENT_H
-#define _ASM_SEGMENT_H
-
-#include <asm/cache.h>
-
-#define __KERNEL_CS	0x10
-#define __KERNEL_DS	0x1b
-
-#define __KERNEL32_CS   0x3b
-
-/* 
- * we cannot use the same code segment descriptor for user and kernel
- * -- not even in the long flat mode, because of different DPL /kkeil 
- * The segment offset needs to contain a RPL. Grr. -AK
- * GDT layout to get 64bit syscall right (sysret hardcodes gdt offsets) 
- */
-
-#define __USER32_CS   0x23   /* 4*8+3 */ 
-#define __USER_DS     0x2b   /* 5*8+3 */ 
-#define __USER_CS     0x33   /* 6*8+3 */ 
-#define __USER32_DS	__USER_DS 
-#define __KERNEL16_CS	(GDT_ENTRY_KERNELCS16 * 8)
-#define __KERNEL_COMPAT32_CS   0x8
-
-#define GDT_ENTRY_TLS 1
-#define GDT_ENTRY_TSS 8	/* needs two entries */
-#define GDT_ENTRY_LDT 10 /* needs two entries */
-#define GDT_ENTRY_TLS_MIN 12
-#define GDT_ENTRY_TLS_MAX 14
-#define GDT_ENTRY_KERNELCS16 15
-
-#define GDT_ENTRY_TLS_ENTRIES 3
-
-/* TLS indexes for 64bit - hardcoded in arch_prctl */
-#define FS_TLS 0	
-#define GS_TLS 1	
-
-#define GS_TLS_SEL ((GDT_ENTRY_TLS_MIN+GS_TLS)*8 + 3)
-#define FS_TLS_SEL ((GDT_ENTRY_TLS_MIN+FS_TLS)*8 + 3)
-
-#define IDT_ENTRIES 256
-#define GDT_ENTRIES 16
-#define GDT_SIZE (GDT_ENTRIES * 8)
-#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8) 
-
-#endif
Index: 2006-01-05/include/asm-x86_64/segment.h
===================================================================
--- 2006-01-05.orig/include/asm-x86_64/segment.h	2006-01-09 16:17:27.589367688 +0100
+++ 2006-01-05/include/asm-x86_64/segment.h	2006-01-09 12:03:33.000000000 +0100
@@ -1,12 +1,17 @@
 #ifndef _ASM_SEGMENT_H
 #define _ASM_SEGMENT_H
 
+#include <linux/config.h>
 #include <asm/cache.h>
 
-#define __KERNEL_CS	0x10
-#define __KERNEL_DS	0x18
+#ifndef CONFIG_XEN
+#define KERNEL_RPL 0
+#else
+#define KERNEL_RPL 3
+#endif
 
-#define __KERNEL32_CS   0x38
+#define __KERNEL_CS	0x10
+#define __KERNEL_DS	(0x18 | KERNEL_RPL)
 
 /* 
  * we cannot use the same code segment descriptor for user and kernel
@@ -19,15 +24,20 @@
 #define __USER_DS     0x2b   /* 5*8+3 */ 
 #define __USER_CS     0x33   /* 6*8+3 */ 
 #define __USER32_DS	__USER_DS 
+#ifndef CONFIG_XEN
 #define __KERNEL16_CS	(GDT_ENTRY_KERNELCS16 * 8)
 #define __KERNEL_COMPAT32_CS   0x8
+#define __KERNEL32_CS   0x38
+#endif
 
 #define GDT_ENTRY_TLS 1
 #define GDT_ENTRY_TSS 8	/* needs two entries */
 #define GDT_ENTRY_LDT 10 /* needs two entries */
 #define GDT_ENTRY_TLS_MIN 12
 #define GDT_ENTRY_TLS_MAX 14
+#ifndef CONFIG_XEN
 #define GDT_ENTRY_KERNELCS16 15
+#endif
 
 #define GDT_ENTRY_TLS_ENTRIES 3