diff --git a/target/arm/arm-semi.c b/target/arm/arm-semi.c
index 384b011..86e6ec4 100644
--- a/target/arm/arm-semi.c
+++ b/target/arm/arm-semi.c
@@ -28,6 +28,7 @@
 #include "cpu.h"
 #include "hw/semihosting/semihost.h"
 #include "hw/semihosting/console.h"
+#include "qemu/log.h"
 #ifdef CONFIG_USER_ONLY
 #include "qemu.h"
 
@@ -363,7 +364,7 @@
             return len - ret;
         }
     case TARGET_SYS_READC:
-       /* XXX: Read from debug console. Not implemented.  */
+        qemu_log_mask(LOG_UNIMP, "%s: SYS_READC not implemented", __func__);
         return 0;
     case TARGET_SYS_ISTTY:
         GET_ARG(0);
@@ -397,7 +398,7 @@
             return buf.st_size;
         }
     case TARGET_SYS_TMPNAM:
-        /* XXX: Not implemented.  */
+        qemu_log_mask(LOG_UNIMP, "%s: SYS_TMPNAM not implemented", __func__);
         return -1;
     case TARGET_SYS_REMOVE:
         GET_ARG(0);