Revert "kdb: Get rid of confusing diag msg from "rd" if current task has no regs"

This reverts commit bbfceba1.

When DBG_MAX_REG_NUM is zero then a number of symbols are conditionally
defined. It is therefore not possible to check it using C expressions.
Reported-by: Anatoly Pugachev <matorola@gmail.com>
Acked-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>

kernel/debug/kdb/kdb_main.c

@@ -543,8 +543,9 @@ int kdbgetaddrarg(int argc, const char **argv, int *nextarg,
 		if (diag)
 			return diag;
 	} else if (symname[0] == '%') {
-		if (kdb_check_regs())
-			return 0;
+		diag = kdb_check_regs();
+		if (diag)
+			return diag;
 		/* Implement register values with % at a later time as it is
 		 * arch optional.
 		 */
@@ -1835,7 +1836,8 @@ static int kdb_go(int argc, const char **argv)
  */
 static int kdb_rd(int argc, const char **argv)
 {
-	int len = 0;
+	int len = kdb_check_regs();
+#if DBG_MAX_REG_NUM > 0
 	int i;
 	char *rname;
 	int rsize;
@@ -1844,14 +1846,8 @@ static int kdb_rd(int argc, const char **argv)
 	u16 reg16;
 	u8 reg8;
 
-	if (kdb_check_regs())
-		return 0;
-
-	/* Fallback to Linux showregs() if we don't have DBG_MAX_REG_NUM */
-	if (DBG_MAX_REG_NUM <= 0) {
-		kdb_dumpregs(kdb_current_regs);
-		return 0;
-	}
+	if (len)
+		return len;
 
 	for (i = 0; i < DBG_MAX_REG_NUM; i++) {
 		rsize = dbg_reg_def[i].size * 2;
@@ -1893,7 +1889,12 @@ static int kdb_rd(int argc, const char **argv)
 		}
 	}
 	kdb_printf("\n");
+#else
+	if (len)
+		return len;
 
+	kdb_dumpregs(kdb_current_regs);
+#endif
 	return 0;
 }
 
@@ -1927,8 +1928,9 @@ static int kdb_rm(int argc, const char **argv)
 	if (diag)
 		return diag;
 
-	if (kdb_check_regs())
-		return 0;
+	diag = kdb_check_regs();
+	if (diag)
+		return diag;
 
 	diag = KDB_BADREG;
 	for (i = 0; i < DBG_MAX_REG_NUM; i++) {