diff --git a/library/psa_crypto_mac.c b/library/psa_crypto_mac.c
index 6972472..9db9a37 100644
--- a/library/psa_crypto_mac.c
+++ b/library/psa_crypto_mac.c
@@ -347,6 +347,9 @@
     else
 #endif /* BUILTIN_ALG_HMAC */
     {
+        (void) attributes;
+        (void) key_buffer;
+        (void) key_buffer_size;
         status = PSA_ERROR_NOT_SUPPORTED;
     }
 
@@ -430,6 +433,8 @@
     {
         /* This shouldn't happen if `operation` was initialized by
          * a setup function. */
+        (void) input;
+        (void) input_length;
         return( PSA_ERROR_BAD_STATE );
     }
 }