diff --git a/arch/sparc/prom/bootstr_32.c b/arch/sparc/prom/bootstr_32.c
index f5ec32e..25cda1c 100644
--- a/arch/sparc/prom/bootstr_32.c
+++ b/arch/sparc/prom/bootstr_32.c
@@ -40,6 +40,10 @@ prom_getbootargs(void)
 				*cp++ = *arg++;
 			}
 			*cp++ = ' ';
+			if(cp >= barg_buf + BARG_LEN-1){
+				/* We might issue a warning here. */
+				break;
+			}
 		}
 		*cp = 0;
 		break;