diff --git a/arch/sim/src/sim/up_heap.c b/arch/sim/src/sim/up_heap.c
index 16ace89b586..e57279d3715 100644
--- a/arch/sim/src/sim/up_heap.c
+++ b/arch/sim/src/sim/up_heap.c
@@ -135,7 +135,8 @@ void mm_initialize(FAR struct mm_heap_s *heap, FAR void *heap_start,
                    size_t heap_size)
 {
   FAR struct mm_heap_impl_s *impl;
-  impl = host_malloc(sizeof(struct mm_heap_impl_s));
+
+  impl = host_memalign(sizeof(FAR void *), sizeof(*impl));
   impl->mm_delaylist = NULL;
   heap->mm_impl = impl;
 }
@@ -176,10 +177,7 @@ void mm_addregion(FAR struct mm_heap_s *heap, FAR void *heapstart,
 
 FAR void *mm_malloc(FAR struct mm_heap_s *heap, size_t size)
 {
-  /* Firstly, free mm_delaylist */
-
-  mm_free_delaylist(heap);
-  return host_malloc(size);
+  return mm_realloc(heap, NULL, size);
 }
 
 /****************************************************************************
@@ -218,8 +216,6 @@ FAR void mm_free(FAR struct mm_heap_s *heap, FAR void *mem)
     {
       host_free(mem);
     }
-
-  return;
 }
 
 /****************************************************************************
@@ -262,8 +258,14 @@ FAR void *mm_realloc(FAR struct mm_heap_s *heap, FAR void *oldmem,
 
 FAR void *mm_calloc(FAR struct mm_heap_s *heap, size_t n, size_t elem_size)
 {
-  mm_free_delaylist(heap);
-  return host_calloc(n, elem_size);
+  size_t size = n * elem_size;
+
+  if (size < elem_size)
+    {
+      return NULL;
+    }
+
+  return mm_zalloc(heap, size);
 }
 
 /****************************************************************************
diff --git a/arch/sim/src/sim/up_hostmemory.c b/arch/sim/src/sim/up_hostmemory.c
index 0f024ae2f75..e8238b00389 100644
--- a/arch/sim/src/sim/up_hostmemory.c
+++ b/arch/sim/src/sim/up_hostmemory.c
@@ -119,26 +119,6 @@ void host_free_shmem(void *mem)
   munmap(mem, 0);
 }
 
-void *host_malloc(size_t size)
-{
-  return malloc(size);
-}
-
-void host_free(void *mem)
-{
-  free(mem);
-}
-
-void *host_realloc(void *oldmem, size_t size)
-{
-  return realloc(oldmem, size);
-}
-
-void *host_calloc(size_t n, size_t elem_size)
-{
-  return calloc(n , elem_size);
-}
-
 void *host_memalign(size_t alignment, size_t size)
 {
   void *p;
@@ -153,6 +133,16 @@ void *host_memalign(size_t alignment, size_t size)
   return p;
 }
 
+void host_free(void *mem)
+{
+  free(mem);
+}
+
+void *host_realloc(void *oldmem, size_t size)
+{
+  return realloc(oldmem, size);
+}
+
 void host_mallinfo(struct host_mallinfo *info)
 {
   struct mallinfo tmp;
diff --git a/arch/sim/src/sim/up_internal.h b/arch/sim/src/sim/up_internal.h
index 706d7b6cecc..0e074369ab6 100644
--- a/arch/sim/src/sim/up_internal.h
+++ b/arch/sim/src/sim/up_internal.h
@@ -158,11 +158,10 @@ void host_abort(int status);
 void *host_alloc_heap(size_t sz);
 void *host_alloc_shmem(const char *name, size_t size, int master);
 void  host_free_shmem(void *mem);
-void *host_malloc(size_t size);
+
+void *host_memalign(size_t alignment, size_t size);
 void host_free(void *mem);
 void *host_realloc(void *oldmem, size_t size);
-void *host_calloc(size_t n, size_t elem_size);
-void *host_memalign(size_t alignment, size_t size);
 
 /* up_hosttime.c ************************************************************/