diff --git a/arch/sim/src/sim/sim_sectionheap.c b/arch/sim/src/sim/sim_sectionheap.c
index 8a9e0b3625be4..5e3db77fd1a7f 100644
--- a/arch/sim/src/sim/sim_sectionheap.c
+++ b/arch/sim/src/sim/sim_sectionheap.c
@@ -33,7 +33,9 @@
  * Private Data
  ****************************************************************************/
 
+#ifdef CONFIG_ARCH_USE_TEXT_HEAP
 static struct mm_heap_s *g_textheap;
+#endif
 static struct mm_heap_s *g_dataheap;
 
 /****************************************************************************
@@ -48,6 +50,7 @@ static struct mm_heap_s *g_dataheap;
  *
  ****************************************************************************/
 
+#ifdef CONFIG_ARCH_USE_TEXT_HEAP
 #ifdef CONFIG_ARCH_USE_SEPARATED_SECTION
 void *up_textheap_memalign(const char *sectname, size_t align, size_t size)
 #else
@@ -92,6 +95,7 @@ bool up_textheap_heapmember(void *p)
 {
   return g_textheap != NULL && mm_heapmember(g_textheap, p);
 }
+#endif /* CONFIG_ARCH_USE_TEXT_HEAP */
 
 /****************************************************************************
  * Name: up_dataheap_memalign
diff --git a/include/nuttx/arch.h b/include/nuttx/arch.h
index e1a598c222b2d..2d705f5fc197d 100644
--- a/include/nuttx/arch.h
+++ b/include/nuttx/arch.h
@@ -847,6 +847,11 @@ void up_extraheaps_init(void);
  * Description:
  *   Allocate memory for text with the specified alignment and sectname.
  *
+ *   If the architecture does not provide a separate text heap
+ *   (CONFIG_ARCH_USE_TEXT_HEAP is not set), the text heap API falls back
+ *   to the normal kernel heap: on flat-memory architectures the kernel
+ *   heap is executable, so no separate allocator is needed.
+ *
  ****************************************************************************/
 
 #if defined(CONFIG_ARCH_USE_TEXT_HEAP)
@@ -856,6 +861,12 @@ FAR void *up_textheap_memalign(FAR const char *sectname,
 #  else
 FAR void *up_textheap_memalign(size_t align, size_t size);
 #  endif
+#else
+#  if defined(CONFIG_ARCH_USE_SEPARATED_SECTION)
+#    define up_textheap_memalign(s,a,z) kmm_memalign(a,z)
+#  else
+#    define up_textheap_memalign(a,z) kmm_memalign(a,z)
+#  endif
 #endif
 
 /****************************************************************************
@@ -868,6 +879,8 @@ FAR void *up_textheap_memalign(size_t align, size_t size);
 
 #if defined(CONFIG_ARCH_USE_TEXT_HEAP)
 void up_textheap_free(FAR void *p);
+#else
+#  define up_textheap_free(p) kmm_free(p)
 #endif
 
 /****************************************************************************
@@ -880,6 +893,8 @@ void up_textheap_free(FAR void *p);
 
 #if defined(CONFIG_ARCH_USE_TEXT_HEAP)
 bool up_textheap_heapmember(FAR void *p);
+#else
+#  define up_textheap_heapmember(p) kmm_heapmember(p)
 #endif
 
 /****************************************************************************
@@ -900,13 +915,12 @@ bool up_textheap_heapmember(FAR void *p);
  *
  ****************************************************************************/
 
-#if defined(CONFIG_ARCH_USE_TEXT_HEAP)
-#if defined(CONFIG_ARCH_HAVE_TEXT_HEAP_SEPARATE_DATA_ADDRESS)
+#if defined(CONFIG_ARCH_USE_TEXT_HEAP) && \
+    defined(CONFIG_ARCH_HAVE_TEXT_HEAP_SEPARATE_DATA_ADDRESS)
 FAR void *up_textheap_data_address(FAR void *p);
 #else
 #define up_textheap_data_address(p) ((FAR void *)p)
 #endif
-#endif
 
 /****************************************************************************
  * Name: up_textheap_data_sync
@@ -918,13 +932,12 @@ FAR void *up_textheap_data_address(FAR void *p);
  *
  ****************************************************************************/
 
-#if defined(CONFIG_ARCH_USE_TEXT_HEAP)
-#if defined(CONFIG_ARCH_HAVE_TEXT_HEAP_SEPARATE_DATA_ADDRESS)
+#if defined(CONFIG_ARCH_USE_TEXT_HEAP) && \
+    defined(CONFIG_ARCH_HAVE_TEXT_HEAP_SEPARATE_DATA_ADDRESS)
 void up_textheap_data_sync(void);
 #else
 #define up_textheap_data_sync() do {} while (0)
 #endif
-#endif
 
 /****************************************************************************
  * Name: up_dataheap_memalign