Add 'hwatch' and 'dhwatch' ddb commands analogous to 'watch' and

'dwatch'.  The new commands install hardware watchpoints if supported
by the architecture and if there are enough registers to cover the
desired memory area.

No objection by: audit@, hackers@

MFC after: 2 weeks

9 files changed, 699 insertions, 140 deletions

diff --git a/sys/alpha/alpha/db_trace.c b/sys/alpha/alpha/db_trace.c
index c522379..c743926 100644
--- a/sys/alpha/alpha/db_trace.c
+++ b/sys/alpha/alpha/db_trace.c
@@ -96,6 +96,12 @@ static struct special_symbol {
 	{ NULL }
 };
 
+
+int  db_md_set_watchpoint   __P((db_expr_t addr, db_expr_t size));
+int  db_md_clr_watchpoint   __P((db_expr_t addr, db_expr_t size));
+void db_md_list_watchpoints __P((void));
+
+
 /*
  * Decode the function prologue for the function we're in, and note
  * which registers are stored where, and how large the stack frame is.
@@ -367,3 +373,30 @@ db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count, char *m
 		frame += pi.pi_frame_size;
 	}
 }
+
+
+
+int
+db_md_set_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	return (-1);
+}
+
+
+int
+db_md_clr_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	return (-1);
+}
+
+
+void
+db_md_list_watchpoints()
+{
+	return;
+}
+
diff --git a/sys/amd64/amd64/db_trace.c b/sys/amd64/amd64/db_trace.c
index a861d16..dc1e2f0 100644
--- a/sys/amd64/amd64/db_trace.c
+++ b/sys/amd64/amd64/db_trace.c
@@ -34,6 +34,8 @@
 #include <sys/user.h>
 
 #include <machine/cpu.h>
+#include <machine/md_var.h>
+#include <machine/reg.h>
 
 #include <vm/vm.h>
 #include <vm/vm_param.h>
@@ -107,6 +109,16 @@ static int db_numargs __P((struct i386_frame *));
 static void db_print_stack_entry __P((const char *, int, char **, int *, db_addr_t));
 static void decode_syscall __P((int, struct proc *));
 
+
+static char * watchtype_str __P((int type));
+int  i386_set_watch         __P((int watchnum, unsigned int watchaddr, 
+                                 int size, int access, struct dbreg * d));
+int  i386_clr_watch         __P((int watchnum, struct dbreg * d));
+int  db_md_set_watchpoint   __P((db_expr_t addr, db_expr_t size));
+int  db_md_clr_watchpoint   __P((db_expr_t addr, db_expr_t size));
+void db_md_list_watchpoints __P((void));
+
+
 /*
  * Figure out how many arguments were passed into the frame at "fp".
  */
@@ -427,7 +439,7 @@ db_stack_trace_cmd(addr, have_addr, count, modif)
 	}
 }
 
-#define DB_DRX_FUNC(reg)                \
+#define DB_DRX_FUNC(reg)		\
 int					\
 db_ ## reg (vp, valuep, op)		\
 	struct db_variable *vp;		\
@@ -450,3 +462,191 @@ DB_DRX_FUNC(dr4)
 DB_DRX_FUNC(dr5)
 DB_DRX_FUNC(dr6)
 DB_DRX_FUNC(dr7)
+
+
+
+int
+i386_set_watch(watchnum, watchaddr, size, access, d)
+	int watchnum;
+	unsigned int watchaddr;
+	int size;
+	int access;
+	struct dbreg * d;
+{
+	int i;
+	unsigned int mask;
+	
+	if (watchnum == -1) {
+		for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2)
+			if ((d->dr7 & mask) == 0)
+				break;
+		if (i < 4)
+			watchnum = i;
+		else
+			return (-1);
+	}
+	
+	switch (access) {
+	case DBREG_DR7_EXEC:
+		size = 1; /* size must be 1 for an execution breakpoint */
+		/* fall through */
+	case DBREG_DR7_WRONLY:
+	case DBREG_DR7_RDWR:
+		break;
+	default : return (-1); break;
+	}
+	
+	/*
+	 * we can watch a 1, 2, or 4 byte sized location
+	 */
+	switch (size) {
+	case 1	: mask = 0x00; break;
+	case 2	: mask = 0x01 << 2; break;
+	case 4	: mask = 0x03 << 2; break;
+	default : return (-1); break;
+	}
+
+	mask |= access;
+
+	/* clear the bits we are about to affect */
+	d->dr7 &= ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
+
+	/* set drN register to the address, N=watchnum */
+	DBREG_DRX(d,watchnum) = watchaddr;
+
+	/* enable the watchpoint */
+	d->dr7 |= (0x2 << (watchnum*2)) | (mask << (watchnum*4+16));
+
+	return (watchnum);
+}
+
+
+int
+i386_clr_watch(watchnum, d)
+	int watchnum;
+	struct dbreg * d;
+{
+
+	if (watchnum < 0 || watchnum >= 4)
+		return (-1);
+	
+	d->dr7 = d->dr7 & ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
+	DBREG_DRX(d,watchnum) = 0;
+	
+	return (0);
+}
+
+
+int
+db_md_set_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	int avail, wsize;
+	int i;
+	struct dbreg d;
+	
+	fill_dbregs(NULL, &d);
+	
+	avail = 0;
+	for(i=0; i<4; i++) {
+		if ((d.dr7 & (3 << (i*2))) == 0)
+			avail++;
+	}
+	
+	if (avail*4 < size)
+		return (-1);
+	
+	for (i=0; i<4 && (size != 0); i++) {
+		if ((d.dr7 & (3<<(i*2))) == 0) {
+			if (size > 4)
+				wsize = 4;
+			else
+				wsize = size;
+			if (wsize == 3)
+				wsize++;
+			i386_set_watch(i, addr, wsize, 
+				       DBREG_DR7_WRONLY, &d);
+			addr += wsize;
+			size -= wsize;
+		}
+	}
+	
+	set_dbregs(NULL, &d);
+	
+	return(0);
+}
+
+
+int
+db_md_clr_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	int i;
+	struct dbreg d;
+
+	fill_dbregs(NULL, &d);
+
+	for(i=0; i<4; i++) {
+		if (d.dr7 & (3 << (i*2))) {
+			if ((DBREG_DRX((&d), i) >= addr) && 
+			    (DBREG_DRX((&d), i) < addr+size))
+				i386_clr_watch(i, &d);
+			
+		}
+	}
+	
+	set_dbregs(NULL, &d);
+	
+	return(0);
+}
+
+
+static 
+char *
+watchtype_str(type)
+	int type;
+{
+	switch (type) {
+		case DBREG_DR7_EXEC   : return "execute";    break;
+		case DBREG_DR7_RDWR   : return "read/write"; break;
+		case DBREG_DR7_WRONLY : return "write";	     break;
+		default		      : return "invalid";    break;
+	}
+}
+
+
+void
+db_md_list_watchpoints()
+{
+	int i;
+	struct dbreg d;
+
+	fill_dbregs(NULL, &d);
+
+	db_printf("\nhardware watchpoints:\n");
+	db_printf("  watch    status        type  len     address\n"
+		  "  -----  --------  ----------  ---  ----------\n");
+	for (i=0; i<4; i++) {
+		if (d.dr7 & (0x03 << (i*2))) {
+			unsigned type, len;
+			type = (d.dr7 >> (16+(i*4))) & 3;
+			len =  (d.dr7 >> (16+(i*4)+2)) & 3;
+			db_printf("  %-5d  %-8s  %10s  %3d  0x%08x\n",
+				  i, "enabled", watchtype_str(type), 
+				  len+1, DBREG_DRX((&d),i));
+		}
+		else {
+			db_printf("  %-5d  disabled\n", i);
+		}
+	}
+	
+	db_printf("\ndebug register values:\n");
+	for (i=0; i<8; i++) {
+		db_printf("  dr%d 0x%08x\n", i, DBREG_DRX((&d),i));
+	}
+	db_printf("\n");
+}
+
+
diff --git a/sys/amd64/amd64/machdep.c b/sys/amd64/amd64/machdep.c
index 9ee7bfc..544aff5 100644
--- a/sys/amd64/amd64/machdep.c
+++ b/sys/amd64/amd64/machdep.c
@@ -2186,15 +2186,27 @@ fill_dbregs(p, 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;
+	if (p == NULL) {
+		dbregs->dr0 = rdr0();
+		dbregs->dr1 = rdr1();
+		dbregs->dr2 = rdr2();
+		dbregs->dr3 = rdr3();
+		dbregs->dr4 = rdr4();
+		dbregs->dr5 = rdr5();
+		dbregs->dr6 = rdr6();
+		dbregs->dr7 = rdr7();
+	}
+	else {
+		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);
 }
 
@@ -2207,74 +2219,84 @@ set_dbregs(p, dbregs)
 	int i;
 	u_int32_t mask1, mask2;
 
-	/*
-	 * Don't let an illegal value for dr7 get set.  Specifically,
-	 * check for undefined settings.  Setting these bit patterns
-	 * result in undefined behaviour and can lead to an unexpected
-	 * TRCTRAP.
-	 */
-	for (i = 0, mask1 = 0x3<<16, mask2 = 0x2<<16; i < 8; 
-	     i++, mask1 <<= 2, mask2 <<= 2)
-		if ((dbregs->dr7 & mask1) == mask2)
+	if (p == NULL) {
+		load_dr0(dbregs->dr0);
+		load_dr1(dbregs->dr1);
+		load_dr2(dbregs->dr2);
+		load_dr3(dbregs->dr3);
+		load_dr4(dbregs->dr4);
+		load_dr5(dbregs->dr5);
+		load_dr6(dbregs->dr6);
+		load_dr7(dbregs->dr7);
+	}
+	else {
+		/*
+		 * Don't let an illegal value for dr7 get set.	Specifically,
+		 * check for undefined settings.  Setting these bit patterns
+		 * result in undefined behaviour and can lead to an unexpected
+		 * TRCTRAP.
+		 */
+		for (i = 0, mask1 = 0x3<<16, mask2 = 0x2<<16; i < 8; 
+		     i++, mask1 <<= 2, mask2 <<= 2)
+			if ((dbregs->dr7 & mask1) == mask2)
+				return (EINVAL);
+		
+		if (dbregs->dr7 & 0x0000fc00)
 			return (EINVAL);
 
-	if (dbregs->dr7 & 0x0000fc00)
-		return (EINVAL);
-
-
-
-	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 (suser(p) != 0) {
-		if (dbregs->dr7 & 0x3) {
-			/* dr0 is enabled */
-			if (dbregs->dr0 >= VM_MAXUSER_ADDRESS)
-				return (EINVAL);
-		}
+		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 (dbregs->dr7 & (0x3<<2)) {
-			/* dr1 is enabled */
-			if (dbregs->dr1 >= VM_MAXUSER_ADDRESS)
-				return (EINVAL);
+		if (suser(p) != 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);
+			}
 		}
 
-		if (dbregs->dr7 & (0x3<<4)) {
-			/* dr2 is enabled */
-			if (dbregs->dr2 >= 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;
 
-		if (dbregs->dr7 & (0x3<<6)) {
-			/* dr3 is enabled */
-			if (dbregs->dr3 >= VM_MAXUSER_ADDRESS)
-				return (EINVAL);
-		}
+		pcb->pcb_flags |= PCB_DBREGS;
 	}
 
-	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);
 }
 
diff --git a/sys/ddb/db_command.c b/sys/ddb/db_command.c
index 64cad7e..dfcc9c3 100644
--- a/sys/ddb/db_command.c
+++ b/sys/ddb/db_command.c
@@ -401,6 +401,8 @@ static struct command db_command_table[] = {
 	{ "break",	db_breakpoint_cmd,	0,	0 },
 	{ "dwatch",	db_deletewatch_cmd,	0,	0 },
 	{ "watch",	db_watchpoint_cmd,	CS_MORE,0 },
+	{ "dhwatch",	db_deletehwatch_cmd,	0,      0 },
+	{ "hwatch",	db_hwatchpoint_cmd,	0,      0 },
 	{ "step",	db_single_step_cmd,	0,	0 },
 	{ "s",		db_single_step_cmd,	0,	0 },
 	{ "continue",	db_continue_cmd,	0,	0 },
diff --git a/sys/ddb/db_watch.c b/sys/ddb/db_watch.c
index 079013a..abfb853 100644
--- a/sys/ddb/db_watch.c
+++ b/sys/ddb/db_watch.c
@@ -67,6 +67,10 @@ static void		db_list_watchpoints __P((void));
 static void		db_set_watchpoint __P((vm_map_t map, db_addr_t addr,
 				       vm_size_t size));
 
+int  db_md_set_watchpoint   __P((db_expr_t addr, db_expr_t size));
+int  db_md_clr_watchpoint   __P((db_expr_t addr, db_expr_t size));
+void db_md_list_watchpoints __P((void));
+
 
 db_watchpoint_t
 db_watchpoint_alloc()
@@ -220,6 +224,7 @@ db_watchpoint_cmd(addr, have_addr, count, modif)
 DB_SHOW_COMMAND(watches, db_listwatch_cmd)
 {
 	db_list_watchpoints();
+	db_md_list_watchpoints();
 }
 
 void
@@ -282,3 +287,43 @@ db_find_watchpoint(map, addr, regs)
 	return (FALSE);
 }
 #endif
+
+
+
+/* Delete hardware watchpoint */
+/*ARGSUSED*/
+void
+db_deletehwatch_cmd(addr, have_addr, count, modif)
+	db_expr_t	addr;
+	boolean_t	have_addr;
+	db_expr_t	count;
+	char *		modif;
+{
+	int rc;
+
+        if (count < 0)
+                count = 4;
+
+	rc = db_md_clr_watchpoint(addr, count);
+	if (rc < 0)
+		db_printf("hardware watchpoint could not be deleted\n");
+}
+
+/* Set hardware watchpoint */
+/*ARGSUSED*/
+void
+db_hwatchpoint_cmd(addr, have_addr, count, modif)
+	db_expr_t	addr;
+	boolean_t	have_addr;
+	db_expr_t	count;
+	char *		modif;
+{
+	int rc;
+
+        if (count < 0)
+                count = 4;
+
+	rc = db_md_set_watchpoint(addr, count);
+	if (rc < 0)
+		db_printf("hardware watchpoint could not be set\n");
+}
diff --git a/sys/ddb/ddb.h b/sys/ddb/ddb.h
index 972772f..df602d0 100644
--- a/sys/ddb/ddb.h
+++ b/sys/ddb/ddb.h
@@ -109,8 +109,10 @@ void		kdb_init __P((void));
 db_cmdfcn_t	db_breakpoint_cmd;
 db_cmdfcn_t	db_continue_cmd;
 db_cmdfcn_t	db_delete_cmd;
+db_cmdfcn_t	db_deletehwatch_cmd;
 db_cmdfcn_t	db_deletewatch_cmd;
 db_cmdfcn_t	db_examine_cmd;
+db_cmdfcn_t	db_hwatchpoint_cmd;
 db_cmdfcn_t	db_listbreak_cmd;
 db_cmdfcn_t	db_print_cmd;
 db_cmdfcn_t	db_ps;
diff --git a/sys/i386/i386/db_trace.c b/sys/i386/i386/db_trace.c
index a861d16..dc1e2f0 100644
--- a/sys/i386/i386/db_trace.c
+++ b/sys/i386/i386/db_trace.c
@@ -34,6 +34,8 @@
 #include <sys/user.h>
 
 #include <machine/cpu.h>
+#include <machine/md_var.h>
+#include <machine/reg.h>
 
 #include <vm/vm.h>
 #include <vm/vm_param.h>
@@ -107,6 +109,16 @@ static int db_numargs __P((struct i386_frame *));
 static void db_print_stack_entry __P((const char *, int, char **, int *, db_addr_t));
 static void decode_syscall __P((int, struct proc *));
 
+
+static char * watchtype_str __P((int type));
+int  i386_set_watch         __P((int watchnum, unsigned int watchaddr, 
+                                 int size, int access, struct dbreg * d));
+int  i386_clr_watch         __P((int watchnum, struct dbreg * d));
+int  db_md_set_watchpoint   __P((db_expr_t addr, db_expr_t size));
+int  db_md_clr_watchpoint   __P((db_expr_t addr, db_expr_t size));
+void db_md_list_watchpoints __P((void));
+
+
 /*
  * Figure out how many arguments were passed into the frame at "fp".
  */
@@ -427,7 +439,7 @@ db_stack_trace_cmd(addr, have_addr, count, modif)
 	}
 }
 
-#define DB_DRX_FUNC(reg)                \
+#define DB_DRX_FUNC(reg)		\
 int					\
 db_ ## reg (vp, valuep, op)		\
 	struct db_variable *vp;		\
@@ -450,3 +462,191 @@ DB_DRX_FUNC(dr4)
 DB_DRX_FUNC(dr5)
 DB_DRX_FUNC(dr6)
 DB_DRX_FUNC(dr7)
+
+
+
+int
+i386_set_watch(watchnum, watchaddr, size, access, d)
+	int watchnum;
+	unsigned int watchaddr;
+	int size;
+	int access;
+	struct dbreg * d;
+{
+	int i;
+	unsigned int mask;
+	
+	if (watchnum == -1) {
+		for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2)
+			if ((d->dr7 & mask) == 0)
+				break;
+		if (i < 4)
+			watchnum = i;
+		else
+			return (-1);
+	}
+	
+	switch (access) {
+	case DBREG_DR7_EXEC:
+		size = 1; /* size must be 1 for an execution breakpoint */
+		/* fall through */
+	case DBREG_DR7_WRONLY:
+	case DBREG_DR7_RDWR:
+		break;
+	default : return (-1); break;
+	}
+	
+	/*
+	 * we can watch a 1, 2, or 4 byte sized location
+	 */
+	switch (size) {
+	case 1	: mask = 0x00; break;
+	case 2	: mask = 0x01 << 2; break;
+	case 4	: mask = 0x03 << 2; break;
+	default : return (-1); break;
+	}
+
+	mask |= access;
+
+	/* clear the bits we are about to affect */
+	d->dr7 &= ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
+
+	/* set drN register to the address, N=watchnum */
+	DBREG_DRX(d,watchnum) = watchaddr;
+
+	/* enable the watchpoint */
+	d->dr7 |= (0x2 << (watchnum*2)) | (mask << (watchnum*4+16));
+
+	return (watchnum);
+}
+
+
+int
+i386_clr_watch(watchnum, d)
+	int watchnum;
+	struct dbreg * d;
+{
+
+	if (watchnum < 0 || watchnum >= 4)
+		return (-1);
+	
+	d->dr7 = d->dr7 & ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
+	DBREG_DRX(d,watchnum) = 0;
+	
+	return (0);
+}
+
+
+int
+db_md_set_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	int avail, wsize;
+	int i;
+	struct dbreg d;
+	
+	fill_dbregs(NULL, &d);
+	
+	avail = 0;
+	for(i=0; i<4; i++) {
+		if ((d.dr7 & (3 << (i*2))) == 0)
+			avail++;
+	}
+	
+	if (avail*4 < size)
+		return (-1);
+	
+	for (i=0; i<4 && (size != 0); i++) {
+		if ((d.dr7 & (3<<(i*2))) == 0) {
+			if (size > 4)
+				wsize = 4;
+			else
+				wsize = size;
+			if (wsize == 3)
+				wsize++;
+			i386_set_watch(i, addr, wsize, 
+				       DBREG_DR7_WRONLY, &d);
+			addr += wsize;
+			size -= wsize;
+		}
+	}
+	
+	set_dbregs(NULL, &d);
+	
+	return(0);
+}
+
+
+int
+db_md_clr_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	int i;
+	struct dbreg d;
+
+	fill_dbregs(NULL, &d);
+
+	for(i=0; i<4; i++) {
+		if (d.dr7 & (3 << (i*2))) {
+			if ((DBREG_DRX((&d), i) >= addr) && 
+			    (DBREG_DRX((&d), i) < addr+size))
+				i386_clr_watch(i, &d);
+			
+		}
+	}
+	
+	set_dbregs(NULL, &d);
+	
+	return(0);
+}
+
+
+static 
+char *
+watchtype_str(type)
+	int type;
+{
+	switch (type) {
+		case DBREG_DR7_EXEC   : return "execute";    break;
+		case DBREG_DR7_RDWR   : return "read/write"; break;
+		case DBREG_DR7_WRONLY : return "write";	     break;
+		default		      : return "invalid";    break;
+	}
+}
+
+
+void
+db_md_list_watchpoints()
+{
+	int i;
+	struct dbreg d;
+
+	fill_dbregs(NULL, &d);
+
+	db_printf("\nhardware watchpoints:\n");
+	db_printf("  watch    status        type  len     address\n"
+		  "  -----  --------  ----------  ---  ----------\n");
+	for (i=0; i<4; i++) {
+		if (d.dr7 & (0x03 << (i*2))) {
+			unsigned type, len;
+			type = (d.dr7 >> (16+(i*4))) & 3;
+			len =  (d.dr7 >> (16+(i*4)+2)) & 3;
+			db_printf("  %-5d  %-8s  %10s  %3d  0x%08x\n",
+				  i, "enabled", watchtype_str(type), 
+				  len+1, DBREG_DRX((&d),i));
+		}
+		else {
+			db_printf("  %-5d  disabled\n", i);
+		}
+	}
+	
+	db_printf("\ndebug register values:\n");
+	for (i=0; i<8; i++) {
+		db_printf("  dr%d 0x%08x\n", i, DBREG_DRX((&d),i));
+	}
+	db_printf("\n");
+}
+
+
diff --git a/sys/i386/i386/machdep.c b/sys/i386/i386/machdep.c
index 9ee7bfc..544aff5 100644
--- a/sys/i386/i386/machdep.c
+++ b/sys/i386/i386/machdep.c
@@ -2186,15 +2186,27 @@ fill_dbregs(p, 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;
+	if (p == NULL) {
+		dbregs->dr0 = rdr0();
+		dbregs->dr1 = rdr1();
+		dbregs->dr2 = rdr2();
+		dbregs->dr3 = rdr3();
+		dbregs->dr4 = rdr4();
+		dbregs->dr5 = rdr5();
+		dbregs->dr6 = rdr6();
+		dbregs->dr7 = rdr7();
+	}
+	else {
+		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);
 }
 
@@ -2207,74 +2219,84 @@ set_dbregs(p, dbregs)
 	int i;
 	u_int32_t mask1, mask2;
 
-	/*
-	 * Don't let an illegal value for dr7 get set.  Specifically,
-	 * check for undefined settings.  Setting these bit patterns
-	 * result in undefined behaviour and can lead to an unexpected
-	 * TRCTRAP.
-	 */
-	for (i = 0, mask1 = 0x3<<16, mask2 = 0x2<<16; i < 8; 
-	     i++, mask1 <<= 2, mask2 <<= 2)
-		if ((dbregs->dr7 & mask1) == mask2)
+	if (p == NULL) {
+		load_dr0(dbregs->dr0);
+		load_dr1(dbregs->dr1);
+		load_dr2(dbregs->dr2);
+		load_dr3(dbregs->dr3);
+		load_dr4(dbregs->dr4);
+		load_dr5(dbregs->dr5);
+		load_dr6(dbregs->dr6);
+		load_dr7(dbregs->dr7);
+	}
+	else {
+		/*
+		 * Don't let an illegal value for dr7 get set.	Specifically,
+		 * check for undefined settings.  Setting these bit patterns
+		 * result in undefined behaviour and can lead to an unexpected
+		 * TRCTRAP.
+		 */
+		for (i = 0, mask1 = 0x3<<16, mask2 = 0x2<<16; i < 8; 
+		     i++, mask1 <<= 2, mask2 <<= 2)
+			if ((dbregs->dr7 & mask1) == mask2)
+				return (EINVAL);
+		
+		if (dbregs->dr7 & 0x0000fc00)
 			return (EINVAL);
 
-	if (dbregs->dr7 & 0x0000fc00)
-		return (EINVAL);
-
-
-
-	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 (suser(p) != 0) {
-		if (dbregs->dr7 & 0x3) {
-			/* dr0 is enabled */
-			if (dbregs->dr0 >= VM_MAXUSER_ADDRESS)
-				return (EINVAL);
-		}
+		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 (dbregs->dr7 & (0x3<<2)) {
-			/* dr1 is enabled */
-			if (dbregs->dr1 >= VM_MAXUSER_ADDRESS)
-				return (EINVAL);
+		if (suser(p) != 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);
+			}
 		}
 
-		if (dbregs->dr7 & (0x3<<4)) {
-			/* dr2 is enabled */
-			if (dbregs->dr2 >= 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;
 
-		if (dbregs->dr7 & (0x3<<6)) {
-			/* dr3 is enabled */
-			if (dbregs->dr3 >= VM_MAXUSER_ADDRESS)
-				return (EINVAL);
-		}
+		pcb->pcb_flags |= PCB_DBREGS;
 	}
 
-	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);
 }
 
diff --git a/sys/ia64/ia64/db_trace.c b/sys/ia64/ia64/db_trace.c
index e30e340..3fc7909 100644
--- a/sys/ia64/ia64/db_trace.c
+++ b/sys/ia64/ia64/db_trace.c
@@ -36,6 +36,12 @@
 #include <ddb/db_variables.h>
 #include <ddb/db_output.h>
 
+
+int  db_md_set_watchpoint   __P((db_expr_t addr, db_expr_t size));
+int  db_md_clr_watchpoint   __P((db_expr_t addr, db_expr_t size));
+void db_md_list_watchpoints __P((void));
+
+
 void
 db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count, char *modif)
 {
@@ -99,3 +105,30 @@ db_stack_trace_cmd(db_expr_t addr, boolean_t have_addr, db_expr_t count, char *m
 			break;
 	}
 }
+
+
+
+int
+db_md_set_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	return (-1);
+}
+
+
+int
+db_md_clr_watchpoint(addr, size)
+	db_expr_t addr;
+	db_expr_t size;
+{
+	return (-1);
+}
+
+
+void
+db_md_list_watchpoints()
+{
+	return;
+}
+