diff --git a/sys/amd64/amd64/cpu_switch.S b/sys/amd64/amd64/cpu_switch.S
index 428b0ae2d573..82c9737261e2 100644
--- a/sys/amd64/amd64/cpu_switch.S
+++ b/sys/amd64/amd64/cpu_switch.S
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: swtch.s,v 1.82 1999/06/01 18:19:45 jlemon Exp $
+ *	$Id: swtch.s,v 1.83 1999/07/03 06:33:24 alc Exp $
  */
 
 #include "npx.h"
@@ -480,6 +480,26 @@ ENTRY(cpu_switch)
 	movl	%edi,PCB_EDI(%edx)
 	movl	%gs,PCB_GS(%edx)
 
+	/* test if debug regisers should be saved */
+	movb    PCB_FLAGS(%edx),%al
+	andb    $PCB_DBREGS,%al
+	jz      1f                              /* no, skip over */
+	movl    %dr7,%eax                       /* yes, do the save */
+	movl    %eax,PCB_DR7(%edx)
+	andl    $0x0000ff00, %eax               /* disable all watchpoints */
+	movl    %eax,%dr7
+	movl    %dr6,%eax
+	movl    %eax,PCB_DR6(%edx)
+	movl    %dr3,%eax
+	movl    %eax,PCB_DR3(%edx)
+	movl    %dr2,%eax
+	movl    %eax,PCB_DR2(%edx)
+	movl    %dr1,%eax
+	movl    %eax,PCB_DR1(%edx)
+	movl    %dr0,%eax
+	movl    %eax,PCB_DR0(%edx)
+1:
+ 
 #ifdef SMP
 	movl	_mp_lock, %eax
 	/* XXX FIXME: we should be saving the local APIC TPR */
@@ -718,6 +738,24 @@ swtch_com:
 cpu_switch_load_gs:
 	movl	PCB_GS(%edx),%gs
 
+	/* test if debug regisers should be restored */
+	movb    PCB_FLAGS(%edx),%al
+	andb    $PCB_DBREGS,%al
+	jz      1f                              /* no, skip over */
+	movl    PCB_DR6(%edx),%eax              /* yes, do the restore */
+	movl    %eax,%dr6
+	movl    PCB_DR3(%edx),%eax
+	movl    %eax,%dr3
+	movl    PCB_DR2(%edx),%eax
+	movl    %eax,%dr2
+	movl    PCB_DR1(%edx),%eax
+	movl    %eax,%dr1
+	movl    PCB_DR0(%edx),%eax
+	movl    %eax,%dr0
+	movl    PCB_DR7(%edx),%eax
+	movl    %eax,%dr7
+1:
+
 	sti
 	ret
 
diff --git a/sys/amd64/amd64/genassym.c b/sys/amd64/amd64/genassym.c
index 3e92787bf852..dc5a18d61bf7 100644
--- a/sys/amd64/amd64/genassym.c
+++ b/sys/amd64/amd64/genassym.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)genassym.c	5.11 (Berkeley) 5/10/91
- *	$Id: genassym.c,v 1.71 1999/06/28 09:21:41 peter Exp $
+ *	$Id: genassym.c,v 1.72 1999/07/06 07:13:32 cracauer Exp $
  */
 
 #include "opt_user_ldt.h"
@@ -128,6 +128,13 @@ main()
 	printf("#define\tTSS_ESP0 %#x\n", OS(i386tss, tss_esp0));
 	printf("#define\tPCB_USERLDT %#x\n", OS(pcb, pcb_ldt));
 	printf("#define\tPCB_GS %#x\n", OS(pcb, pcb_gs));
+	printf("#define\tPCB_DR0 %#x\n", OS(pcb, pcb_dr0));
+	printf("#define\tPCB_DR1 %#x\n", OS(pcb, pcb_dr1));
+	printf("#define\tPCB_DR2 %#x\n", OS(pcb, pcb_dr2));
+	printf("#define\tPCB_DR3 %#x\n", OS(pcb, pcb_dr3));
+	printf("#define\tPCB_DR6 %#x\n", OS(pcb, pcb_dr6));
+	printf("#define\tPCB_DR7 %#x\n", OS(pcb, pcb_dr7));
+	printf("#define\tPCB_DBREGS %#x\n", PCB_DBREGS );
 	printf("#define\tPCB_EXT %#x\n", OS(pcb, pcb_ext));
 #ifdef SMP
 	printf("#define\tPCB_MPNEST %#x\n", OS(pcb, pcb_mpnest));
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index ec11c9827bd1..423de1258cf7 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)machdep.c	7.4 (Berkeley) 6/3/91
- *	$Id: machdep.c,v 1.353 1999/07/06 07:13:33 cracauer Exp $
+ *	$Id: machdep.c,v 1.354 1999/07/08 06:05:48 mckusick Exp $
  */
 
 #include "apm.h"
@@ -1927,6 +1927,87 @@ set_fpregs(p, fpregs)
 	return (0);
 }
 
+int
+fill_dbregs(p, dbregs)
+	struct proc *p;
+	struct dbreg *dbregs;
+{
+	struct pcb *pcb;
+
+	pcb = &p->p_addr->u_pcb;
+	dbregs->dr0 = pcb->pcb_dr0;
+	dbregs->dr1 = pcb->pcb_dr1;
+	dbregs->dr2 = pcb->pcb_dr2;
+	dbregs->dr3 = pcb->pcb_dr3;
+	dbregs->dr4 = 0;
+	dbregs->dr5 = 0;
+	dbregs->dr6 = pcb->pcb_dr6;
+	dbregs->dr7 = pcb->pcb_dr7;
+	return (0);
+}
+
+int
+set_dbregs(p, dbregs)
+	struct proc *p;
+	struct dbreg *dbregs;
+{
+	struct pcb *pcb;
+
+	pcb = &p->p_addr->u_pcb;
+
+	/*
+	 * Don't let a process set a breakpoint that is not within the
+	 * process's address space.  If a process could do this, it
+	 * could halt the system by setting a breakpoint in the kernel
+	 * (if ddb was enabled).  Thus, we need to check to make sure
+	 * that no breakpoints are being enabled for addresses outside
+	 * process's address space, unless, perhaps, we were called by
+	 * uid 0.
+	 *
+	 * XXX - what about when the watched area of the user's
+	 * address space is written into from within the kernel
+	 * ... wouldn't that still cause a breakpoint to be generated
+	 * from within kernel mode?
+	 */
+
+	if (p->p_cred->pc_ucred->cr_uid != 0) {
+		if (dbregs->dr7 & 0x3) {
+			/* dr0 is enabled */
+			if (dbregs->dr0 >= VM_MAXUSER_ADDRESS)
+				return (EINVAL);
+		}
+
+		if (dbregs->dr7 & (0x3<<2)) {
+			/* dr1 is enabled */
+			if (dbregs->dr1 >= VM_MAXUSER_ADDRESS)
+				return (EINVAL);
+		}
+
+		if (dbregs->dr7 & (0x3<<4)) {
+			/* dr2 is enabled */
+			if (dbregs->dr2 >= VM_MAXUSER_ADDRESS)
+       				return (EINVAL);
+		}
+
+		if (dbregs->dr7 & (0x3<<6)) {
+			/* dr3 is enabled */
+			if (dbregs->dr3 >= VM_MAXUSER_ADDRESS)
+				return (EINVAL);
+		}
+	}
+
+	pcb->pcb_dr0 = dbregs->dr0;
+	pcb->pcb_dr1 = dbregs->dr1;
+	pcb->pcb_dr2 = dbregs->dr2;
+	pcb->pcb_dr3 = dbregs->dr3;
+	pcb->pcb_dr6 = dbregs->dr6;
+	pcb->pcb_dr7 = dbregs->dr7;
+
+	pcb->pcb_flags |= PCB_DBREGS;
+
+	return (0);
+}
+
 #ifndef DDB
 void
 Debugger(const char *msg)
diff --git a/sys/amd64/amd64/swtch.s b/sys/amd64/amd64/swtch.s
index 428b0ae2d573..82c9737261e2 100644
--- a/sys/amd64/amd64/swtch.s
+++ b/sys/amd64/amd64/swtch.s
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: swtch.s,v 1.82 1999/06/01 18:19:45 jlemon Exp $
+ *	$Id: swtch.s,v 1.83 1999/07/03 06:33:24 alc Exp $
  */
 
 #include "npx.h"
@@ -480,6 +480,26 @@ ENTRY(cpu_switch)
 	movl	%edi,PCB_EDI(%edx)
 	movl	%gs,PCB_GS(%edx)
 
+	/* test if debug regisers should be saved */
+	movb    PCB_FLAGS(%edx),%al
+	andb    $PCB_DBREGS,%al
+	jz      1f                              /* no, skip over */
+	movl    %dr7,%eax                       /* yes, do the save */
+	movl    %eax,PCB_DR7(%edx)
+	andl    $0x0000ff00, %eax               /* disable all watchpoints */
+	movl    %eax,%dr7
+	movl    %dr6,%eax
+	movl    %eax,PCB_DR6(%edx)
+	movl    %dr3,%eax
+	movl    %eax,PCB_DR3(%edx)
+	movl    %dr2,%eax
+	movl    %eax,PCB_DR2(%edx)
+	movl    %dr1,%eax
+	movl    %eax,PCB_DR1(%edx)
+	movl    %dr0,%eax
+	movl    %eax,PCB_DR0(%edx)
+1:
+ 
 #ifdef SMP
 	movl	_mp_lock, %eax
 	/* XXX FIXME: we should be saving the local APIC TPR */
@@ -718,6 +738,24 @@ swtch_com:
 cpu_switch_load_gs:
 	movl	PCB_GS(%edx),%gs
 
+	/* test if debug regisers should be restored */
+	movb    PCB_FLAGS(%edx),%al
+	andb    $PCB_DBREGS,%al
+	jz      1f                              /* no, skip over */
+	movl    PCB_DR6(%edx),%eax              /* yes, do the restore */
+	movl    %eax,%dr6
+	movl    PCB_DR3(%edx),%eax
+	movl    %eax,%dr3
+	movl    PCB_DR2(%edx),%eax
+	movl    %eax,%dr2
+	movl    PCB_DR1(%edx),%eax
+	movl    %eax,%dr1
+	movl    PCB_DR0(%edx),%eax
+	movl    %eax,%dr0
+	movl    PCB_DR7(%edx),%eax
+	movl    %eax,%dr7
+1:
+
 	sti
 	ret
 
diff --git a/sys/amd64/include/md_var.h b/sys/amd64/include/md_var.h
index 35b65455e244..491eb46b024a 100644
--- a/sys/amd64/include/md_var.h
+++ b/sys/amd64/include/md_var.h
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: md_var.h,v 1.28 1999/01/08 16:29:58 bde Exp $
+ *	$Id: md_var.h,v 1.29 1999/04/28 01:04:02 luoqi Exp $
  */
 
 #ifndef _MACHINE_MD_VAR_H_
@@ -64,6 +64,7 @@ typedef void alias_for_inthand_t __P((u_int cs, u_int ef, u_int esp, u_int ss));
 struct	proc;
 struct	reg;
 struct	fpreg;
+struct  dbreg;
 
 void	bcopyb __P((const void *from, void *to, size_t len));
 void	busdma_swi __P((void));
@@ -80,6 +81,7 @@ void	doreti_popl_fs __P((void)) __asm(__STRING(doreti_popl_fs));
 void	doreti_popl_fs_fault __P((void)) __asm(__STRING(doreti_popl_fs_fault));
 int	fill_fpregs __P((struct proc *, struct fpreg *));
 int	fill_regs __P((struct proc *p, struct reg *regs));
+int	fill_dbregs __P((struct proc *p, struct dbreg *dbregs));
 void	fillw __P((int /*u_short*/ pat, void *base, size_t cnt));
 void	i486_bzero __P((void *buf, size_t len));
 void	i586_bcopy __P((const void *from, void *to, size_t len));
diff --git a/sys/amd64/include/pcb.h b/sys/amd64/include/pcb.h
index 2dbc707d0fcc..5cee924dd9ff 100644
--- a/sys/amd64/include/pcb.h
+++ b/sys/amd64/include/pcb.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)pcb.h	5.10 (Berkeley) 5/12/91
- *	$Id: pcb.h,v 1.27 1999/04/28 01:04:05 luoqi Exp $
+ *	$Id: pcb.h,v 1.28 1999/06/01 18:20:06 jlemon Exp $
  */
 
 #ifndef _I386_PCB_H_
@@ -54,11 +54,20 @@ struct pcb {
 	int	pcb_esp;
 	int	pcb_ebx;
 	int	pcb_eip;
+
+	int     pcb_dr0;
+	int     pcb_dr1;
+	int     pcb_dr2;
+	int     pcb_dr3;
+	int     pcb_dr6;
+	int     pcb_dr7;
+
 	caddr_t	pcb_ldt;		/* per process (user) LDT */
 	int	pcb_ldt_len;		/* number of LDT entries */
 	struct	save87	pcb_savefpu;	/* floating point state for 287/387 */
 	u_char	pcb_flags;
 #define	FP_SOFTFP	0x01	/* process using software fltng pnt emulator */
+#define	PCB_DBREGS	0x02	/* process using debug registers */
 	caddr_t	pcb_onfault;	/* copyin/out fault recovery */
 #ifdef SMP
 	u_long	pcb_mpnest;
diff --git a/sys/amd64/include/ptrace.h b/sys/amd64/include/ptrace.h
index ec3d5aab5ca5..2c43a2eef8d4 100644
--- a/sys/amd64/include/ptrace.h
+++ b/sys/amd64/include/ptrace.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ptrace.h	8.1 (Berkeley) 6/11/93
- * $Id: ptrace.h,v 1.5 1997/02/22 09:35:03 peter Exp $
+ * $Id: ptrace.h,v 1.6 1998/05/19 00:00:12 tegge Exp $
  */
 
 #ifndef _MACHINE_PTRACE_H_
@@ -44,6 +44,8 @@
 #define PT_SETREGS      (PT_FIRSTMACH + 2)
 #define PT_GETFPREGS    (PT_FIRSTMACH + 3)
 #define PT_SETFPREGS    (PT_FIRSTMACH + 4)
+#define PT_GETDBREGS    (PT_FIRSTMACH + 5)
+#define PT_SETDBREGS    (PT_FIRSTMACH + 6)
 
 #ifdef KERNEL
 int	ptrace_read_u_check __P((struct proc *p, vm_offset_t off, size_t len));
diff --git a/sys/amd64/include/reg.h b/sys/amd64/include/reg.h
index 247011646fa5..994bdfda0360 100644
--- a/sys/amd64/include/reg.h
+++ b/sys/amd64/include/reg.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)reg.h	5.5 (Berkeley) 1/18/91
- *	$Id: reg.h,v 1.17 1999/04/03 22:19:59 jdp Exp $
+ *	$Id: reg.h,v 1.18 1999/04/28 01:04:06 luoqi Exp $
  */
 
 #ifndef _MACHINE_REG_H_
@@ -118,6 +118,18 @@ struct fpreg {
 	unsigned char	fpr_pad[64];
 };
 
+struct dbreg {
+	unsigned int  dr0;	/* debug address register 0 */
+	unsigned int  dr1;	/* debug address register 1 */
+	unsigned int  dr2;	/* debug address register 2 */
+	unsigned int  dr3;	/* debug address register 3 */
+	unsigned int  dr4;	/* reserved */
+	unsigned int  dr5;	/* reserved */
+	unsigned int  dr6;	/* debug status register */
+	unsigned int  dr7;	/* debug control register */
+};
+
+
 #ifdef KERNEL
 /*
  * XXX these interfaces are MI, so they should be declared in a MI place.
@@ -125,6 +137,7 @@ struct fpreg {
 int	set_fpregs __P((struct proc *, struct fpreg *));
 int	set_regs __P((struct proc *p, struct reg *regs));
 void	setregs __P((struct proc *, u_long, u_long, u_long));
+int	set_dbregs __P((struct proc *p, struct dbreg *dbregs));
 #endif
 
 #endif /* !_MACHINE_REG_H_ */
diff --git a/sys/conf/files b/sys/conf/files
index 5d9bb0511996..241d71b2d24b 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -362,6 +362,7 @@ miscfs/nullfs/null_vnops.c	optional nullfs
 miscfs/portal/portal_vfsops.c	optional portal
 miscfs/portal/portal_vnops.c	optional portal
 miscfs/procfs/procfs_ctl.c	optional procfs
+miscfs/procfs/procfs_dbregs.c	standard
 miscfs/procfs/procfs_fpregs.c	standard
 miscfs/procfs/procfs_map.c	optional procfs
 miscfs/procfs/procfs_mem.c	standard
diff --git a/sys/fs/procfs/procfs.h b/sys/fs/procfs/procfs.h
index b38ed872dc8b..f813070e699e 100644
--- a/sys/fs/procfs/procfs.h
+++ b/sys/fs/procfs/procfs.h
@@ -37,7 +37,7 @@
  *	@(#)procfs.h	8.9 (Berkeley) 5/14/95
  *
  * From:
- *	$Id: procfs.h,v 1.25 1999/05/04 08:00:10 phk Exp $
+ *	$Id: procfs.h,v 1.26 1999/06/13 20:53:13 phk Exp $
  */
 
 /*
@@ -51,6 +51,7 @@ typedef enum {
 	Pmem,		/* the process's memory image */
 	Pregs,		/* the process's register set */
 	Pfpregs,	/* the process's FP register set */
+	Pdbregs,	/* the process's debug register set */
 	Pctl,		/* process control */
 	Pstatus,	/* process status */
 	Pnote,		/* process notifier */
@@ -124,6 +125,7 @@ vfs_namemap_t *vfs_findname __P((vfs_namemap_t *, char *, int));
 /* <machine/reg.h> */
 struct reg;
 struct fpreg;
+struct dbreg;
 
 #define PFIND(pid) ((pid) ? pfind(pid) : &proc0)
 
@@ -137,9 +139,12 @@ int procfs_read_regs __P((struct proc *, struct reg *));
 int procfs_write_regs __P((struct proc *, struct reg *));
 int procfs_read_fpregs __P((struct proc *, struct fpreg *));
 int procfs_write_fpregs __P((struct proc *, struct fpreg *));
+int procfs_read_dbregs __P((struct proc *, struct dbreg *));
+int procfs_write_dbregs __P((struct proc *, struct dbreg *));
 int procfs_donote __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_doregs __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_dofpregs __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
+int procfs_dodbregs __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_domem __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_doctl __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_dostatus __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
@@ -155,6 +160,7 @@ int procfs_kmemaccess __P((struct proc *));
 int procfs_validfile __P((struct proc *));
 int procfs_validfpregs __P((struct proc *));
 int procfs_validregs __P((struct proc *));
+int procfs_validdbregs __P((struct proc *));
 int procfs_validmap __P((struct proc *));
 int procfs_validtype __P((struct proc *));
 
diff --git a/sys/fs/procfs/procfs_subr.c b/sys/fs/procfs/procfs_subr.c
index 7b5e18c440d5..cf313e863856 100644
--- a/sys/fs/procfs/procfs_subr.c
+++ b/sys/fs/procfs/procfs_subr.c
@@ -36,7 +36,7 @@
  *
  *	@(#)procfs_subr.c	8.6 (Berkeley) 5/14/95
  *
- *	$Id: procfs_subr.c,v 1.23 1999/01/27 22:42:07 dillon Exp $
+ *	$Id: procfs_subr.c,v 1.24 1999/04/30 13:04:21 phk Exp $
  */
 
 #include <sys/param.h>
@@ -167,6 +167,7 @@ loop:
 
 	case Pregs:
 	case Pfpregs:
+	case Pdbregs:
 		pfs->pfs_mode = (VREAD|VWRITE);
 		vp->v_type = VREG;
 		break;
@@ -264,6 +265,10 @@ procfs_rw(ap)
 		rtval = procfs_dofpregs(curp, p, pfs, uio);
 		break;
 
+        case Pdbregs:
+                rtval = procfs_dodbregs(curp, p, pfs, uio);
+                break;
+
 	case Pctl:
 		rtval = procfs_doctl(curp, p, pfs, uio);
 		break;
diff --git a/sys/fs/procfs/procfs_vnops.c b/sys/fs/procfs/procfs_vnops.c
index d421bac0e3b8..fc47353f62ce 100644
--- a/sys/fs/procfs/procfs_vnops.c
+++ b/sys/fs/procfs/procfs_vnops.c
@@ -36,7 +36,7 @@
  *
  *	@(#)procfs_vnops.c	8.18 (Berkeley) 5/21/95
  *
- *	$Id: procfs_vnops.c,v 1.68 1999/05/04 08:01:55 phk Exp $
+ *	$Id: procfs_vnops.c,v 1.69 1999/06/13 20:53:16 phk Exp $
  */
 
 /*
@@ -95,6 +95,7 @@ static struct proc_target {
 	{ DT_REG, N("mem"),	Pmem,		NULL },
 	{ DT_REG, N("regs"),	Pregs,		procfs_validregs },
 	{ DT_REG, N("fpregs"),	Pfpregs,	procfs_validfpregs },
+	{ DT_REG, N("dbregs"),	Pdbregs,	procfs_validdbregs },
 	{ DT_REG, N("ctl"),	Pctl,		NULL },
 	{ DT_REG, N("status"),	Pstatus,	NULL },
 	{ DT_REG, N("note"),	Pnote,		NULL },
@@ -491,6 +492,7 @@ procfs_getattr(ap)
 	case Pctl:
 	case Pregs:
 	case Pfpregs:
+	case Pdbregs:
 		if (procp->p_flag & P_SUGID)
 			vap->va_mode &= ~((VREAD|VWRITE)|
 					  ((VREAD|VWRITE)>>3)|
@@ -571,6 +573,10 @@ procfs_getattr(ap)
 		vap->va_bytes = vap->va_size = sizeof(struct fpreg);
 		break;
 
+        case Pdbregs:
+                vap->va_bytes = vap->va_size = sizeof(struct dbreg);
+                break;
+
 	case Ptype:
 	case Pmap:
 	case Pctl:
diff --git a/sys/i386/i386/genassym.c b/sys/i386/i386/genassym.c
index 3e92787bf852..dc5a18d61bf7 100644
--- a/sys/i386/i386/genassym.c
+++ b/sys/i386/i386/genassym.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)genassym.c	5.11 (Berkeley) 5/10/91
- *	$Id: genassym.c,v 1.71 1999/06/28 09:21:41 peter Exp $
+ *	$Id: genassym.c,v 1.72 1999/07/06 07:13:32 cracauer Exp $
  */
 
 #include "opt_user_ldt.h"
@@ -128,6 +128,13 @@ main()
 	printf("#define\tTSS_ESP0 %#x\n", OS(i386tss, tss_esp0));
 	printf("#define\tPCB_USERLDT %#x\n", OS(pcb, pcb_ldt));
 	printf("#define\tPCB_GS %#x\n", OS(pcb, pcb_gs));
+	printf("#define\tPCB_DR0 %#x\n", OS(pcb, pcb_dr0));
+	printf("#define\tPCB_DR1 %#x\n", OS(pcb, pcb_dr1));
+	printf("#define\tPCB_DR2 %#x\n", OS(pcb, pcb_dr2));
+	printf("#define\tPCB_DR3 %#x\n", OS(pcb, pcb_dr3));
+	printf("#define\tPCB_DR6 %#x\n", OS(pcb, pcb_dr6));
+	printf("#define\tPCB_DR7 %#x\n", OS(pcb, pcb_dr7));
+	printf("#define\tPCB_DBREGS %#x\n", PCB_DBREGS );
 	printf("#define\tPCB_EXT %#x\n", OS(pcb, pcb_ext));
 #ifdef SMP
 	printf("#define\tPCB_MPNEST %#x\n", OS(pcb, pcb_mpnest));
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index ec11c9827bd1..423de1258cf7 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)machdep.c	7.4 (Berkeley) 6/3/91
- *	$Id: machdep.c,v 1.353 1999/07/06 07:13:33 cracauer Exp $
+ *	$Id: machdep.c,v 1.354 1999/07/08 06:05:48 mckusick Exp $
  */
 
 #include "apm.h"
@@ -1927,6 +1927,87 @@ set_fpregs(p, fpregs)
 	return (0);
 }
 
+int
+fill_dbregs(p, dbregs)
+	struct proc *p;
+	struct dbreg *dbregs;
+{
+	struct pcb *pcb;
+
+	pcb = &p->p_addr->u_pcb;
+	dbregs->dr0 = pcb->pcb_dr0;
+	dbregs->dr1 = pcb->pcb_dr1;
+	dbregs->dr2 = pcb->pcb_dr2;
+	dbregs->dr3 = pcb->pcb_dr3;
+	dbregs->dr4 = 0;
+	dbregs->dr5 = 0;
+	dbregs->dr6 = pcb->pcb_dr6;
+	dbregs->dr7 = pcb->pcb_dr7;
+	return (0);
+}
+
+int
+set_dbregs(p, dbregs)
+	struct proc *p;
+	struct dbreg *dbregs;
+{
+	struct pcb *pcb;
+
+	pcb = &p->p_addr->u_pcb;
+
+	/*
+	 * Don't let a process set a breakpoint that is not within the
+	 * process's address space.  If a process could do this, it
+	 * could halt the system by setting a breakpoint in the kernel
+	 * (if ddb was enabled).  Thus, we need to check to make sure
+	 * that no breakpoints are being enabled for addresses outside
+	 * process's address space, unless, perhaps, we were called by
+	 * uid 0.
+	 *
+	 * XXX - what about when the watched area of the user's
+	 * address space is written into from within the kernel
+	 * ... wouldn't that still cause a breakpoint to be generated
+	 * from within kernel mode?
+	 */
+
+	if (p->p_cred->pc_ucred->cr_uid != 0) {
+		if (dbregs->dr7 & 0x3) {
+			/* dr0 is enabled */
+			if (dbregs->dr0 >= VM_MAXUSER_ADDRESS)
+				return (EINVAL);
+		}
+
+		if (dbregs->dr7 & (0x3<<2)) {
+			/* dr1 is enabled */
+			if (dbregs->dr1 >= VM_MAXUSER_ADDRESS)
+				return (EINVAL);
+		}
+
+		if (dbregs->dr7 & (0x3<<4)) {
+			/* dr2 is enabled */
+			if (dbregs->dr2 >= VM_MAXUSER_ADDRESS)
+       				return (EINVAL);
+		}
+
+		if (dbregs->dr7 & (0x3<<6)) {
+			/* dr3 is enabled */
+			if (dbregs->dr3 >= VM_MAXUSER_ADDRESS)
+				return (EINVAL);
+		}
+	}
+
+	pcb->pcb_dr0 = dbregs->dr0;
+	pcb->pcb_dr1 = dbregs->dr1;
+	pcb->pcb_dr2 = dbregs->dr2;
+	pcb->pcb_dr3 = dbregs->dr3;
+	pcb->pcb_dr6 = dbregs->dr6;
+	pcb->pcb_dr7 = dbregs->dr7;
+
+	pcb->pcb_flags |= PCB_DBREGS;
+
+	return (0);
+}
+
 #ifndef DDB
 void
 Debugger(const char *msg)
diff --git a/sys/i386/i386/procfs_machdep.c b/sys/i386/i386/procfs_machdep.c
index 03a8d9dd0261..b0f8e3cda6e2 100644
--- a/sys/i386/i386/procfs_machdep.c
+++ b/sys/i386/i386/procfs_machdep.c
@@ -37,7 +37,7 @@
  *	@(#)procfs_machdep.c	8.3 (Berkeley) 1/27/94
  *
  * From:
- *	$Id: procfs_machdep.c,v 1.10 1997/07/20 08:37:22 bde Exp $
+ *	$Id: procfs_machdep.c,v 1.11 1998/09/14 22:43:33 jdp Exp $
  */
 
 /*
@@ -59,6 +59,9 @@
  * procfs_read_fpregs, procfs_write_fpregs
  *	deal with the floating point register set, otherwise as above.
  *
+ * procfs_read_dbregs, procfs_write_dbregs
+ *	deal with the processor debug register set, otherwise as above.
+ *
  * procfs_sstep(proc)
  *	Arrange for the process to trap after executing a single instruction.
  *
@@ -100,6 +103,26 @@ procfs_write_regs(p, regs)
 	return (set_regs(p, regs));
 }
 
+int
+procfs_read_dbregs(p, dbregs)
+	struct proc *p;
+	struct dbreg *dbregs;
+{
+	if ((p->p_flag & P_INMEM) == 0)
+		return (EIO);
+	return (fill_dbregs(p, dbregs));
+}
+
+int
+procfs_write_dbregs(p, dbregs)
+	struct proc *p;
+	struct dbreg *dbregs;
+{
+	if ((p->p_flag & P_INMEM) == 0)
+		return (EIO);
+	return (set_dbregs(p, dbregs));
+}
+
 /*
  * Ptrace doesn't support fpregs at all, and there are no security holes
  * or translations for fpregs, so we can just copy them.
diff --git a/sys/i386/i386/swtch.s b/sys/i386/i386/swtch.s
index 428b0ae2d573..82c9737261e2 100644
--- a/sys/i386/i386/swtch.s
+++ b/sys/i386/i386/swtch.s
@@ -33,7 +33,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: swtch.s,v 1.82 1999/06/01 18:19:45 jlemon Exp $
+ *	$Id: swtch.s,v 1.83 1999/07/03 06:33:24 alc Exp $
  */
 
 #include "npx.h"
@@ -480,6 +480,26 @@ ENTRY(cpu_switch)
 	movl	%edi,PCB_EDI(%edx)
 	movl	%gs,PCB_GS(%edx)
 
+	/* test if debug regisers should be saved */
+	movb    PCB_FLAGS(%edx),%al
+	andb    $PCB_DBREGS,%al
+	jz      1f                              /* no, skip over */
+	movl    %dr7,%eax                       /* yes, do the save */
+	movl    %eax,PCB_DR7(%edx)
+	andl    $0x0000ff00, %eax               /* disable all watchpoints */
+	movl    %eax,%dr7
+	movl    %dr6,%eax
+	movl    %eax,PCB_DR6(%edx)
+	movl    %dr3,%eax
+	movl    %eax,PCB_DR3(%edx)
+	movl    %dr2,%eax
+	movl    %eax,PCB_DR2(%edx)
+	movl    %dr1,%eax
+	movl    %eax,PCB_DR1(%edx)
+	movl    %dr0,%eax
+	movl    %eax,PCB_DR0(%edx)
+1:
+ 
 #ifdef SMP
 	movl	_mp_lock, %eax
 	/* XXX FIXME: we should be saving the local APIC TPR */
@@ -718,6 +738,24 @@ swtch_com:
 cpu_switch_load_gs:
 	movl	PCB_GS(%edx),%gs
 
+	/* test if debug regisers should be restored */
+	movb    PCB_FLAGS(%edx),%al
+	andb    $PCB_DBREGS,%al
+	jz      1f                              /* no, skip over */
+	movl    PCB_DR6(%edx),%eax              /* yes, do the restore */
+	movl    %eax,%dr6
+	movl    PCB_DR3(%edx),%eax
+	movl    %eax,%dr3
+	movl    PCB_DR2(%edx),%eax
+	movl    %eax,%dr2
+	movl    PCB_DR1(%edx),%eax
+	movl    %eax,%dr1
+	movl    PCB_DR0(%edx),%eax
+	movl    %eax,%dr0
+	movl    PCB_DR7(%edx),%eax
+	movl    %eax,%dr7
+1:
+
 	sti
 	ret
 
diff --git a/sys/i386/include/md_var.h b/sys/i386/include/md_var.h
index 35b65455e244..491eb46b024a 100644
--- a/sys/i386/include/md_var.h
+++ b/sys/i386/include/md_var.h
@@ -26,7 +26,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: md_var.h,v 1.28 1999/01/08 16:29:58 bde Exp $
+ *	$Id: md_var.h,v 1.29 1999/04/28 01:04:02 luoqi Exp $
  */
 
 #ifndef _MACHINE_MD_VAR_H_
@@ -64,6 +64,7 @@ typedef void alias_for_inthand_t __P((u_int cs, u_int ef, u_int esp, u_int ss));
 struct	proc;
 struct	reg;
 struct	fpreg;
+struct  dbreg;
 
 void	bcopyb __P((const void *from, void *to, size_t len));
 void	busdma_swi __P((void));
@@ -80,6 +81,7 @@ void	doreti_popl_fs __P((void)) __asm(__STRING(doreti_popl_fs));
 void	doreti_popl_fs_fault __P((void)) __asm(__STRING(doreti_popl_fs_fault));
 int	fill_fpregs __P((struct proc *, struct fpreg *));
 int	fill_regs __P((struct proc *p, struct reg *regs));
+int	fill_dbregs __P((struct proc *p, struct dbreg *dbregs));
 void	fillw __P((int /*u_short*/ pat, void *base, size_t cnt));
 void	i486_bzero __P((void *buf, size_t len));
 void	i586_bcopy __P((const void *from, void *to, size_t len));
diff --git a/sys/i386/include/pcb.h b/sys/i386/include/pcb.h
index 2dbc707d0fcc..5cee924dd9ff 100644
--- a/sys/i386/include/pcb.h
+++ b/sys/i386/include/pcb.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)pcb.h	5.10 (Berkeley) 5/12/91
- *	$Id: pcb.h,v 1.27 1999/04/28 01:04:05 luoqi Exp $
+ *	$Id: pcb.h,v 1.28 1999/06/01 18:20:06 jlemon Exp $
  */
 
 #ifndef _I386_PCB_H_
@@ -54,11 +54,20 @@ struct pcb {
 	int	pcb_esp;
 	int	pcb_ebx;
 	int	pcb_eip;
+
+	int     pcb_dr0;
+	int     pcb_dr1;
+	int     pcb_dr2;
+	int     pcb_dr3;
+	int     pcb_dr6;
+	int     pcb_dr7;
+
 	caddr_t	pcb_ldt;		/* per process (user) LDT */
 	int	pcb_ldt_len;		/* number of LDT entries */
 	struct	save87	pcb_savefpu;	/* floating point state for 287/387 */
 	u_char	pcb_flags;
 #define	FP_SOFTFP	0x01	/* process using software fltng pnt emulator */
+#define	PCB_DBREGS	0x02	/* process using debug registers */
 	caddr_t	pcb_onfault;	/* copyin/out fault recovery */
 #ifdef SMP
 	u_long	pcb_mpnest;
diff --git a/sys/i386/include/ptrace.h b/sys/i386/include/ptrace.h
index ec3d5aab5ca5..2c43a2eef8d4 100644
--- a/sys/i386/include/ptrace.h
+++ b/sys/i386/include/ptrace.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ptrace.h	8.1 (Berkeley) 6/11/93
- * $Id: ptrace.h,v 1.5 1997/02/22 09:35:03 peter Exp $
+ * $Id: ptrace.h,v 1.6 1998/05/19 00:00:12 tegge Exp $
  */
 
 #ifndef _MACHINE_PTRACE_H_
@@ -44,6 +44,8 @@
 #define PT_SETREGS      (PT_FIRSTMACH + 2)
 #define PT_GETFPREGS    (PT_FIRSTMACH + 3)
 #define PT_SETFPREGS    (PT_FIRSTMACH + 4)
+#define PT_GETDBREGS    (PT_FIRSTMACH + 5)
+#define PT_SETDBREGS    (PT_FIRSTMACH + 6)
 
 #ifdef KERNEL
 int	ptrace_read_u_check __P((struct proc *p, vm_offset_t off, size_t len));
diff --git a/sys/i386/include/reg.h b/sys/i386/include/reg.h
index 247011646fa5..994bdfda0360 100644
--- a/sys/i386/include/reg.h
+++ b/sys/i386/include/reg.h
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)reg.h	5.5 (Berkeley) 1/18/91
- *	$Id: reg.h,v 1.17 1999/04/03 22:19:59 jdp Exp $
+ *	$Id: reg.h,v 1.18 1999/04/28 01:04:06 luoqi Exp $
  */
 
 #ifndef _MACHINE_REG_H_
@@ -118,6 +118,18 @@ struct fpreg {
 	unsigned char	fpr_pad[64];
 };
 
+struct dbreg {
+	unsigned int  dr0;	/* debug address register 0 */
+	unsigned int  dr1;	/* debug address register 1 */
+	unsigned int  dr2;	/* debug address register 2 */
+	unsigned int  dr3;	/* debug address register 3 */
+	unsigned int  dr4;	/* reserved */
+	unsigned int  dr5;	/* reserved */
+	unsigned int  dr6;	/* debug status register */
+	unsigned int  dr7;	/* debug control register */
+};
+
+
 #ifdef KERNEL
 /*
  * XXX these interfaces are MI, so they should be declared in a MI place.
@@ -125,6 +137,7 @@ struct fpreg {
 int	set_fpregs __P((struct proc *, struct fpreg *));
 int	set_regs __P((struct proc *p, struct reg *regs));
 void	setregs __P((struct proc *, u_long, u_long, u_long));
+int	set_dbregs __P((struct proc *p, struct dbreg *dbregs));
 #endif
 
 #endif /* !_MACHINE_REG_H_ */
diff --git a/sys/kern/sys_process.c b/sys/kern/sys_process.c
index 41482954a768..814db9845c5e 100644
--- a/sys/kern/sys_process.c
+++ b/sys/kern/sys_process.c
@@ -28,7 +28,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: sys_process.c,v 1.45 1999/04/28 11:37:04 phk Exp $
+ *	$Id: sys_process.c,v 1.46 1999/07/01 22:52:40 peter Exp $
  */
 
 #include <sys/param.h>
@@ -274,6 +274,12 @@ ptrace(curp, uap)
 #endif
 #ifdef PT_SETFPREGS
 	case PT_SETFPREGS:
+#endif
+#ifdef PT_GETDBREGS
+	case PT_GETDBREGS:
+#endif
+#ifdef PT_SETDBREGS
+	case PT_SETDBREGS:
 #endif
 		/* not being traced... */
 		if ((p->p_flag & P_TRACED) == 0)
@@ -502,6 +508,32 @@ ptrace(curp, uap)
 		}
 #endif /* defined(PT_SETFPREGS) || defined(PT_GETFPREGS) */
 
+#ifdef PT_SETDBREGS
+	case PT_SETDBREGS:
+		write = 1;
+		/* fallthrough */
+#endif /* PT_SETDBREGS */
+#ifdef PT_GETDBREGS
+	case PT_GETDBREGS:
+		/* write = 0 above */
+#endif /* PT_SETDBREGS */
+#if defined(PT_SETDBREGS) || defined(PT_GETDBREGS)
+		if (!procfs_validdbregs(p))	/* no P_SYSTEM procs please */
+			return EINVAL;
+		else {
+			iov.iov_base = uap->addr;
+			iov.iov_len = sizeof(struct dbreg);
+			uio.uio_iov = &iov;
+			uio.uio_iovcnt = 1;
+			uio.uio_offset = 0;
+			uio.uio_resid = sizeof(struct dbreg);
+			uio.uio_segflg = UIO_USERSPACE;
+			uio.uio_rw = write ? UIO_WRITE : UIO_READ;
+			uio.uio_procp = curp;
+			return (procfs_dodbregs(curp, p, NULL, &uio));
+		}
+#endif /* defined(PT_SETDBREGS) || defined(PT_GETDBREGS) */
+
 	default:
 		break;
 	}
diff --git a/sys/miscfs/procfs/procfs.h b/sys/miscfs/procfs/procfs.h
index b38ed872dc8b..f813070e699e 100644
--- a/sys/miscfs/procfs/procfs.h
+++ b/sys/miscfs/procfs/procfs.h
@@ -37,7 +37,7 @@
  *	@(#)procfs.h	8.9 (Berkeley) 5/14/95
  *
  * From:
- *	$Id: procfs.h,v 1.25 1999/05/04 08:00:10 phk Exp $
+ *	$Id: procfs.h,v 1.26 1999/06/13 20:53:13 phk Exp $
  */
 
 /*
@@ -51,6 +51,7 @@ typedef enum {
 	Pmem,		/* the process's memory image */
 	Pregs,		/* the process's register set */
 	Pfpregs,	/* the process's FP register set */
+	Pdbregs,	/* the process's debug register set */
 	Pctl,		/* process control */
 	Pstatus,	/* process status */
 	Pnote,		/* process notifier */
@@ -124,6 +125,7 @@ vfs_namemap_t *vfs_findname __P((vfs_namemap_t *, char *, int));
 /* <machine/reg.h> */
 struct reg;
 struct fpreg;
+struct dbreg;
 
 #define PFIND(pid) ((pid) ? pfind(pid) : &proc0)
 
@@ -137,9 +139,12 @@ int procfs_read_regs __P((struct proc *, struct reg *));
 int procfs_write_regs __P((struct proc *, struct reg *));
 int procfs_read_fpregs __P((struct proc *, struct fpreg *));
 int procfs_write_fpregs __P((struct proc *, struct fpreg *));
+int procfs_read_dbregs __P((struct proc *, struct dbreg *));
+int procfs_write_dbregs __P((struct proc *, struct dbreg *));
 int procfs_donote __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_doregs __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_dofpregs __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
+int procfs_dodbregs __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_domem __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_doctl __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
 int procfs_dostatus __P((struct proc *, struct proc *, struct pfsnode *pfsp, struct uio *uio));
@@ -155,6 +160,7 @@ int procfs_kmemaccess __P((struct proc *));
 int procfs_validfile __P((struct proc *));
 int procfs_validfpregs __P((struct proc *));
 int procfs_validregs __P((struct proc *));
+int procfs_validdbregs __P((struct proc *));
 int procfs_validmap __P((struct proc *));
 int procfs_validtype __P((struct proc *));
 
diff --git a/sys/miscfs/procfs/procfs_subr.c b/sys/miscfs/procfs/procfs_subr.c
index 7b5e18c440d5..cf313e863856 100644
--- a/sys/miscfs/procfs/procfs_subr.c
+++ b/sys/miscfs/procfs/procfs_subr.c
@@ -36,7 +36,7 @@
  *
  *	@(#)procfs_subr.c	8.6 (Berkeley) 5/14/95
  *
- *	$Id: procfs_subr.c,v 1.23 1999/01/27 22:42:07 dillon Exp $
+ *	$Id: procfs_subr.c,v 1.24 1999/04/30 13:04:21 phk Exp $
  */
 
 #include <sys/param.h>
@@ -167,6 +167,7 @@ loop:
 
 	case Pregs:
 	case Pfpregs:
+	case Pdbregs:
 		pfs->pfs_mode = (VREAD|VWRITE);
 		vp->v_type = VREG;
 		break;
@@ -264,6 +265,10 @@ procfs_rw(ap)
 		rtval = procfs_dofpregs(curp, p, pfs, uio);
 		break;
 
+        case Pdbregs:
+                rtval = procfs_dodbregs(curp, p, pfs, uio);
+                break;
+
 	case Pctl:
 		rtval = procfs_doctl(curp, p, pfs, uio);
 		break;
diff --git a/sys/miscfs/procfs/procfs_vnops.c b/sys/miscfs/procfs/procfs_vnops.c
index d421bac0e3b8..fc47353f62ce 100644
--- a/sys/miscfs/procfs/procfs_vnops.c
+++ b/sys/miscfs/procfs/procfs_vnops.c
@@ -36,7 +36,7 @@
  *
  *	@(#)procfs_vnops.c	8.18 (Berkeley) 5/21/95
  *
- *	$Id: procfs_vnops.c,v 1.68 1999/05/04 08:01:55 phk Exp $
+ *	$Id: procfs_vnops.c,v 1.69 1999/06/13 20:53:16 phk Exp $
  */
 
 /*
@@ -95,6 +95,7 @@ static struct proc_target {
 	{ DT_REG, N("mem"),	Pmem,		NULL },
 	{ DT_REG, N("regs"),	Pregs,		procfs_validregs },
 	{ DT_REG, N("fpregs"),	Pfpregs,	procfs_validfpregs },
+	{ DT_REG, N("dbregs"),	Pdbregs,	procfs_validdbregs },
 	{ DT_REG, N("ctl"),	Pctl,		NULL },
 	{ DT_REG, N("status"),	Pstatus,	NULL },
 	{ DT_REG, N("note"),	Pnote,		NULL },
@@ -491,6 +492,7 @@ procfs_getattr(ap)
 	case Pctl:
 	case Pregs:
 	case Pfpregs:
+	case Pdbregs:
 		if (procp->p_flag & P_SUGID)
 			vap->va_mode &= ~((VREAD|VWRITE)|
 					  ((VREAD|VWRITE)>>3)|
@@ -571,6 +573,10 @@ procfs_getattr(ap)
 		vap->va_bytes = vap->va_size = sizeof(struct fpreg);
 		break;
 
+        case Pdbregs:
+                vap->va_bytes = vap->va_size = sizeof(struct dbreg);
+                break;
+
 	case Ptype:
 	case Pmap:
 	case Pctl:
diff --git a/sys/powerpc/include/ptrace.h b/sys/powerpc/include/ptrace.h
index ec3d5aab5ca5..2c43a2eef8d4 100644
--- a/sys/powerpc/include/ptrace.h
+++ b/sys/powerpc/include/ptrace.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)ptrace.h	8.1 (Berkeley) 6/11/93
- * $Id: ptrace.h,v 1.5 1997/02/22 09:35:03 peter Exp $
+ * $Id: ptrace.h,v 1.6 1998/05/19 00:00:12 tegge Exp $
  */
 
 #ifndef _MACHINE_PTRACE_H_
@@ -44,6 +44,8 @@
 #define PT_SETREGS      (PT_FIRSTMACH + 2)
 #define PT_GETFPREGS    (PT_FIRSTMACH + 3)
 #define PT_SETFPREGS    (PT_FIRSTMACH + 4)
+#define PT_GETDBREGS    (PT_FIRSTMACH + 5)
+#define PT_SETDBREGS    (PT_FIRSTMACH + 6)
 
 #ifdef KERNEL
 int	ptrace_read_u_check __P((struct proc *p, vm_offset_t off, size_t len));