Plug hw debug register support into kdb

Make the `watch' command use hw debug registers whenever possible.

* ddb/db_watch.c (db_set_hw_watchpoint, db_clear_hw_watchpoint): Add
functions prototypes.
(db_set_watchpoints): Try to call db_set_hw_watchpoint.
(db_clear_watchpoints): Call db_clear_hw_watchpoint.
* i386/i386/db_interface.c: Include <ddb/db_watch.h>
(db_set_hw_watchpoint): Take a db_watchpoint_t WATCH parameter instead of
its content. Remove support for clearing a debug register.
(db_clear_hw_watchpoint): Add function.
* i386/i386/db_interface.h: Include <ddb/db_watch.h>.
(db_set_hw_watchpoint): Fix function prototype.
(db_clear_hw_watchpoint): Add function prototype.
* i386/i386/db_machdep.h: Do not include <machine/db_interface.h>

4 files changed, 47 insertions, 22 deletions

diff --git a/ddb/db_watch.c b/ddb/db_watch.c
index 072f474..7eb9995 100644
--- a/ddb/db_watch.c
+++ b/ddb/db_watch.c
@@ -55,6 +55,9 @@
 
 boolean_t	db_watchpoints_inserted = TRUE;
 
+extern boolean_t db_set_hw_watchpoint(db_watchpoint_t watch, unsigned hw_idx);
+extern boolean_t db_clear_hw_watchpoint(unsigned hw_idx);
+
 #define	NWATCHPOINTS	100
 struct db_watchpoint	db_watch_table[NWATCHPOINTS];
 db_watchpoint_t		db_next_free_watchpoint = &db_watch_table[0];
@@ -264,9 +267,14 @@ db_set_watchpoints(void)
 {
 	register db_watchpoint_t	watch;
 	vm_map_t			map;
+	unsigned hw_idx = 0;
 
 	if (!db_watchpoints_inserted) {
 	    for (watch = db_watchpoint_list; watch != 0; watch = watch->link) {
+		if (db_set_hw_watchpoint(watch, hw_idx)) {
+		    hw_idx++;
+		    continue;
+		}
 		map = (watch->task)? watch->task->map: kernel_map;
 		pmap_protect(map->pmap,
 			     trunc_page(watch->loaddr),
@@ -280,6 +288,11 @@ db_set_watchpoints(void)
 void
 db_clear_watchpoints(void)
 {
+	unsigned hw_idx = 0;
+
+	while (db_clear_hw_watchpoint(hw_idx))
+	    hw_idx++;
+
 	db_watchpoints_inserted = FALSE;
 }
 
diff --git a/i386/i386/db_interface.c b/i386/i386/db_interface.c
index c6d7fb4..90ca22d 100644
--- a/i386/i386/db_interface.c
+++ b/i386/i386/db_interface.c
@@ -53,6 +53,7 @@
 #include <ddb/db_run.h>
 #include <ddb/db_task_thread.h>
 #include <ddb/db_trap.h>
+#include <ddb/db_watch.h>
 #include <machine/db_interface.h>
 #include <machine/machspl.h>
 
@@ -167,29 +168,27 @@ void db_dr (
 	splx(s);
 }
 
-void db_set_hw_watchpoint(
-	int		num,
-	task_t		task,
-	db_addr_t	addr,
-	vm_size_t	size)
+boolean_t
+db_set_hw_watchpoint(
+	db_watchpoint_t	watch,
+	unsigned	num)
 {
+	vm_size_t	size = watch->hiaddr - watch->loaddr;
+	db_addr_t	addr = watch->loaddr;
 	unsigned int kern_addr;
 
+	if (num >= 4)
+	    return FALSE;
 	if (size != 1 && size != 2 && size != 4)
-	    return;
+	    return FALSE;
 
 	if (addr & (size-1))
 	    /* Unaligned */
-	    return;
-
-	if (!addr) {
-	    db_dr (num, 0, 0, 0, 0);
-	    db_printf("Hardware watchpoint %d deleted\n", num);
-	}
+	    return FALSE;
 
-	if (task) {
-	    if (db_user_to_kernel_address(task, addr, &kern_addr, 1) < 0)
-		return;
+	if (watch->task) {
+	    if (db_user_to_kernel_address(watch->task, addr, &kern_addr, 1) < 0)
+		return FALSE;
 	    addr = kern_addr;
 	}
 	addr = kvtolin(addr);
@@ -197,6 +196,18 @@ void db_set_hw_watchpoint(
 	db_dr (num, addr, I386_DB_TYPE_W, size-1, I386_DB_LOCAL|I386_DB_GLOBAL);
 
 	db_printf("Hardware watchpoint %d set for %x\n", num, addr);
+	return TRUE;
+}
+
+boolean_t
+db_clear_hw_watchpoint(
+	unsigned	num)
+{
+	if (num >= 4)
+		return FALSE;
+
+	db_dr (num, 0, 0, 0, 0);
+	return TRUE;
 }
 
 /*
@@ -577,7 +588,7 @@ db_check_access(
 	register int	size,
 	task_t		task)
 {
-	register	n;
+	int	n;
 	vm_offset_t	kern_addr;
 
 	if (addr >= VM_MIN_KERNEL_ADDRESS) {
diff --git a/i386/i386/db_interface.h b/i386/i386/db_interface.h
index a8dfdce..e1b2dff 100644
--- a/i386/i386/db_interface.h
+++ b/i386/i386/db_interface.h
@@ -24,6 +24,7 @@
 #include <sys/types.h>
 #include <kern/task.h>
 #include <machine/thread.h>
+#include <ddb/db_watch.h>
 
 extern boolean_t kdb_trap (
 	int 			type,
@@ -73,11 +74,12 @@ extern void db_task_name (task_t task);
 #define I386_DB_LOCAL 1
 #define I386_DB_GLOBAL 2
 
-extern void db_set_hw_watchpoint(
-	int		num,
-	task_t		task,
-	vm_offset_t	addr,
-	vm_size_t	size);
+extern boolean_t db_set_hw_watchpoint(
+	db_watchpoint_t	watch,
+	unsigned	num);
+
+extern boolean_t db_clear_hw_watchpoint(
+	unsigned	num);
 
 extern void db_dr (
 	int		num,
diff --git a/i386/i386/db_machdep.h b/i386/i386/db_machdep.h
index 1dba2cd..c6ea3ca 100644
--- a/i386/i386/db_machdep.h
+++ b/i386/i386/db_machdep.h
@@ -34,7 +34,6 @@
 #include <mach/machine/vm_types.h>
 #include <mach/machine/vm_param.h>
 #include <mach/machine/eflags.h>
-#include <machine/db_interface.h>
 #include <i386/thread.h>		/* for thread_status */
 #include <i386/trap.h>