Index: sys/amd64/amd64/gdb_machdep.c
===================================================================
--- sys/amd64/amd64/gdb_machdep.c
+++ sys/amd64/amd64/gdb_machdep.c
@@ -48,6 +48,8 @@
 void *
 gdb_cpu_getreg(int regnum, size_t *regsz)
 {
+	static uint32_t _kcodesel = GSEL(GCODE_SEL, SEL_KPL);
+	static uint32_t _kdatasel = GSEL(GDATA_SEL, SEL_KPL);
 
 	*regsz = gdb_cpu_regsz(regnum);
 
@@ -76,6 +78,8 @@
 	case 14: return (&kdb_thrctx->pcb_r14);
 	case 15: return (&kdb_thrctx->pcb_r15);
 	case 16: return (&kdb_thrctx->pcb_rip);
+	case 18: return (&_kcodesel);
+	case 19: return (&_kdatasel);
 	}
 	return (NULL);
 }
Index: sys/i386/i386/exception.s
===================================================================
--- sys/i386/i386/exception.s
+++ sys/i386/i386/exception.s
@@ -157,9 +157,12 @@
 	.type	alltraps,@function
 alltraps:
 	pushal
-	pushl	%ds
-	pushl	%es
-	pushl	%fs
+	pushl	$0
+	movl	%ds,(%esp)
+	pushl	$0
+	movl	%es,(%esp)
+	pushl	$0
+	movl	%fs,(%esp)
 alltraps_with_regs_pushed:
 	SET_KERNEL_SREGS
 	cld
@@ -233,9 +236,12 @@
 	pushl	$7			/* sizeof "lcall 7,0" */
 	subl	$4,%esp			/* skip over tf_trapno */
 	pushal
-	pushl	%ds
-	pushl	%es
-	pushl	%fs
+	pushl	$0
+	movl	%ds,(%esp)
+	pushl	$0
+	movl	%es,(%esp)
+	pushl	$0
+	movl	%fs,(%esp)
 	SET_KERNEL_SREGS
 	cld
 	FAKE_MCOUNT(TF_EIP(%esp))
@@ -259,9 +265,12 @@
 	pushl	$2			/* sizeof "int 0x80" */
 	subl	$4,%esp			/* skip over tf_trapno */
 	pushal
-	pushl	%ds
-	pushl	%es
-	pushl	%fs
+	pushl	$0
+	movl	%ds,(%esp)
+	pushl	$0
+	movl	%es,(%esp)
+	pushl	$0
+	movl	%fs,(%esp)
 	SET_KERNEL_SREGS
 	cld
 	FAKE_MCOUNT(TF_EIP(%esp))
@@ -416,13 +425,16 @@
 doreti_iret_fault:
 	subl	$8,%esp
 	pushal
-	pushl	%ds
+	pushl	$0
+	movl	%ds,(%esp)
 	.globl	doreti_popl_ds_fault
 doreti_popl_ds_fault:
-	pushl	%es
+	pushl	$0
+	movl	%es,(%esp)
 	.globl	doreti_popl_es_fault
 doreti_popl_es_fault:
-	pushl	%fs
+	pushl	$0
+	movl	%fs,(%esp)
 	.globl	doreti_popl_fs_fault
 doreti_popl_fs_fault:
 	sti
Index: sys/i386/i386/gdb_machdep.c
===================================================================
--- sys/i386/i386/gdb_machdep.c
+++ sys/i386/i386/gdb_machdep.c
@@ -45,14 +45,22 @@
 void *
 gdb_cpu_getreg(int regnum, size_t *regsz)
 {
+	static uint32_t _kcodesel = GSEL(GCODE_SEL, SEL_KPL);
+	static uint32_t _kdatasel = GSEL(GDATA_SEL, SEL_KPL);
+	static uint32_t _kprivsel = GSEL(GPRIV_SEL, SEL_KPL);
 
 	*regsz = gdb_cpu_regsz(regnum);
 
-	if (kdb_thread  == curthread) {
+	if (kdb_thread == curthread) {
 		switch (regnum) {
 		case 0:	return (&kdb_frame->tf_eax);
 		case 1:	return (&kdb_frame->tf_ecx);
 		case 2:	return (&kdb_frame->tf_edx);
+		case 9: return (&kdb_frame->tf_eflags);
+		case 10: return (&kdb_frame->tf_cs);
+		case 12: return (&kdb_frame->tf_ds);
+		case 13: return (&kdb_frame->tf_es);
+		case 14: return (&kdb_frame->tf_fs);
 		}
 	}
 	switch (regnum) {
@@ -62,6 +70,12 @@
 	case 6:  return (&kdb_thrctx->pcb_esi);
 	case 7:  return (&kdb_thrctx->pcb_edi);
 	case 8:  return (&kdb_thrctx->pcb_eip);
+	case 10: return (&_kcodesel);
+	case 11: return (&_kdatasel);
+	case 12: return (&_kdatasel);
+	case 13: return (&_kdatasel);
+	case 14: return (&_kprivsel);
+	case 15: return (&kdb_thrctx->pcb_gs);
 	}
 	return (NULL);
 }
Index: sys/i386/i386/machdep.c
===================================================================
--- sys/i386/i386/machdep.c
+++ sys/i386/i386/machdep.c
@@ -2867,6 +2867,7 @@
 	pcb->pcb_ebx = tf->tf_ebx;
 	pcb->pcb_eip = tf->tf_eip;
 	pcb->pcb_esp = (ISPL(tf->tf_cs)) ? tf->tf_esp : (int)(tf + 1) - 8;
+	pcb->pcb_gs = rgs();
 }
 
 int
Index: sys/i386/include/asmacros.h
===================================================================
--- sys/i386/include/asmacros.h
+++ sys/i386/include/asmacros.h
@@ -146,9 +146,12 @@
 	pushl	$0 ;		/* dummy error code */			\
 	pushl	$0 ;		/* dummy trap type */			\
 	pushal ;		/* 8 ints */				\
-	pushl	%ds ;		/* save data and extra segments ... */	\
-	pushl	%es ;							\
-	pushl	%fs
+	pushl	$0 ;		/* save data and extra segments ... */	\
+	mov	%ds,(%esp) ;						\
+	pushl	$0 ;							\
+	mov	%es,(%esp) ;						\
+	pushl	$0 ;							\
+	mov	%fs,(%esp)
 	
 #define	POP_FRAME							\
 	popl	%fs ;							\
Index: sys/i386/include/gdb_machdep.h
===================================================================
--- sys/i386/include/gdb_machdep.h
+++ sys/i386/include/gdb_machdep.h
@@ -30,7 +30,7 @@
 #define	_MACHINE_GDB_MACHDEP_H_
 
 #define	GDB_BUFSZ	400
-#define	GDB_NREGS	14
+#define	GDB_NREGS	16
 #define	GDB_REG_PC	8
 
 static __inline size_t