diff --git a/kernel/copy.c b/kernel/copy.c
index 62aef87f..510c1b2a 100644
--- a/kernel/copy.c
+++ b/kernel/copy.c
@@ -10,6 +10,7 @@
  * HISTORY:
  */
 
+#ifdef USE_DMA
 #include <ihk/dma.h>
 #include <amemcpy.h>
 
@@ -48,3 +49,4 @@ int memcpy_async(unsigned long dest, unsigned long src,
 
 	return 0;
 }
+#endif
diff --git a/kernel/init.c b/kernel/init.c
index 75f52323..39a54993 100644
--- a/kernel/init.c
+++ b/kernel/init.c
@@ -55,6 +55,7 @@ static void handler_init(void)
 
 unsigned long data[1024] __attribute__((aligned(64)));
 
+#ifdef USE_DMA
 static void dma_test(void)
 {
 	struct ihk_dma_request req;
@@ -102,6 +103,7 @@ static void dma_test(void)
 		}
 	}
 }
+#endif
 
 extern char *ihk_mc_get_kernel_args(void);
 
@@ -182,8 +184,10 @@ static void rest_init(void)
 
 	handler_init();
 
+#ifdef USE_DMA
 	ihk_mc_dma_init();
 	dma_test();
+#endif
 	//pc_test();
 
 	ap_init();
diff --git a/kernel/syscall.c b/kernel/syscall.c
index 515b9411..36b32181 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -106,7 +106,6 @@ static void send_syscall(struct syscall_request *req, int cpu)
 	struct ikc_scd_packet packet;
 	struct syscall_response *res;
 	unsigned long fin;
-	int w;
 	struct syscall_params *scp;
 	struct ihk_ikc_channel_desc *syscall_channel;
 
@@ -127,19 +126,20 @@ static void send_syscall(struct syscall_request *req, int cpu)
 	res->status = 0;
 	req->valid = 0;
 
+#ifdef USE_DMA
 	memcpy_async(scp->request_pa,
 	             virt_to_phys(req), sizeof(*req), 0, &fin);
 
 	memcpy_async_wait(&scp->post_fin);
 	scp->post_va->v[0] = scp->post_idx;
-
-	w = cpu + 1;
-
 	memcpy_async_wait(&fin);
+#else
+	memcpy(scp->request_va, req, sizeof(*req));
+#endif
 
 	barrier();
 	scp->request_va->valid = 1;
-	*(unsigned int *)scp->doorbell_va = w;
+	*(unsigned int *)scp->doorbell_va = cpu + 1;
 
 #ifdef SYSCALL_BY_IKC
 	packet.msg = SCD_MSG_SYSCALL_ONESIDE;