watchpoint_add() cleanup

Fail watchpoint_add() if it's the same address but the
parameters are different ... don't just assume having
the same address means the same watchpoint!  (Note that
overlapping watchpoints aren't detected...)

Handle unrecognized return codes more sanely; don't exit()!
And describe command params right.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>

src/target/breakpoints.c

@@ -178,54 +178,61 @@ breakpoint_t* breakpoint_find(target_t *target, uint32_t address)
 	return NULL;
 }
 
-int watchpoint_add(target_t *target, uint32_t address, uint32_t length, enum watchpoint_rw rw, uint32_t value, uint32_t mask)
+int watchpoint_add(target_t *target, uint32_t address, uint32_t length,
+		enum watchpoint_rw rw, uint32_t value, uint32_t mask)
 {
 	watchpoint_t *watchpoint = target->watchpoints;
 	watchpoint_t **watchpoint_p = &target->watchpoints;
 	int retval;
+	char *reason;
 
 	while (watchpoint)
 	{
-		if (watchpoint->address == address)
+		if (watchpoint->address == address) {
+			if (watchpoint->length != length
+					|| watchpoint->value != value
+					|| watchpoint->mask != mask
+					|| watchpoint->rw != rw) {
+				LOG_ERROR("address 0x%8.8" PRIx32
+						"already has watchpoint %d",
+						address, watchpoint->unique_id);
+				return ERROR_FAIL;
+			}
+
+			/* ignore duplicate watchpoint */
 			return ERROR_OK;
+		}
 		watchpoint_p = &watchpoint->next;
 		watchpoint = watchpoint->next;
 	}
 
-	(*watchpoint_p) = malloc(sizeof(watchpoint_t));
+	(*watchpoint_p) = calloc(1, sizeof(watchpoint_t));
 	(*watchpoint_p)->address = address;
 	(*watchpoint_p)->length = length;
 	(*watchpoint_p)->value = value;
 	(*watchpoint_p)->mask = mask;
 	(*watchpoint_p)->rw = rw;
-	(*watchpoint_p)->set = 0;
-	(*watchpoint_p)->next = NULL;
 	(*watchpoint_p)->unique_id = bpwp_unique_id++;
 
-	if ((retval = target_add_watchpoint(target, *watchpoint_p)) != ERROR_OK)
-	{
-		switch (retval)
-		{
-			case ERROR_TARGET_RESOURCE_NOT_AVAILABLE:
-				LOG_INFO("can't add %s watchpoint, resource not available (WPID: %d)",
-					 watchpoint_rw_strings[(*watchpoint_p)->rw],
-					 (*watchpoint_p)->unique_id );
-				free (*watchpoint_p);
-				*watchpoint_p = NULL;
-				return retval;
-				break;
-			case ERROR_TARGET_NOT_HALTED:
-				LOG_INFO("can't add watchpoint while target is running (WPID: %d)",
-						 (*watchpoint_p)->unique_id );
-				free (*watchpoint_p);
-				*watchpoint_p = NULL;
-				return retval;
-				break;
-			default:
-				LOG_ERROR("unknown error");
-				exit(-1);
-				break;
-		}
+	retval = target_add_watchpoint(target, *watchpoint_p);
+	switch (retval) {
+	case ERROR_OK:
+		break;
+	case ERROR_TARGET_RESOURCE_NOT_AVAILABLE:
+		reason = "resource not available";
+		goto bye;
+	case ERROR_TARGET_NOT_HALTED:
+		reason = "target running";
+		goto bye;
+	default:
+		reason = "unrecognized error";
+bye:
+		LOG_ERROR("can't add %s watchpoint at 0x%8.8" PRIx32 ", %s",
+			 watchpoint_rw_strings[(*watchpoint_p)->rw],
+			 address, reason);
+		free (*watchpoint_p);
+		*watchpoint_p = NULL;
+		return retval;
 	}
 
 	LOG_DEBUG("added %s watchpoint at 0x%8.8" PRIx32 " of length 0x%8.8x (WPID: %d)",

src/target/breakpoints.h

@@ -49,7 +49,7 @@ typedef struct breakpoint_s
 typedef struct watchpoint_s
 {
 	uint32_t address;
-	int length;
+	uint32_t length;
 	uint32_t mask;
 	uint32_t value;
 	enum watchpoint_rw rw;

src/target/cortex_m3.c

@@ -1199,7 +1199,7 @@ cortex_m3_add_watchpoint(struct target_s *target, watchpoint_t *watchpoint)
 	unsigned mask;
 
 	for (mask = 0; mask < 16; mask++) {
-		if ((1 << mask) == watchpoint->length)
+		if ((1u << mask) == watchpoint->length)
 			break;
 	}
 	if (mask == 16) {

src/target/target.c

@@ -2988,7 +2988,8 @@ static int handle_wp_command(struct command_context_s *cmd_ctx, char *cmd, char
 		break;
 
 	default:
-		command_print(cmd_ctx, "usage: wp <address> <length> [r/w/a] [value] [mask]");
+		command_print(cmd_ctx, "usage: wp [address length "
+				"[(r|w|a) [value [mask]]]]");
 		return ERROR_COMMAND_SYNTAX_ERROR;
 	}