diff --git a/softmmu_defs.h b/softmmu_defs.h
index e38bb752f1..c5a2bcd3e2 100644
--- a/softmmu_defs.h
+++ b/softmmu_defs.h
@@ -1,3 +1,11 @@
+/*
+ *  Software MMU support
+ *
+ * Declare helpers used by TCG for qemu_ld/st ops.
+ *
+ * Used by softmmu_exec.h, TCG targets and exec-all.h.
+ *
+ */
 #ifndef SOFTMMU_DEFS_H
 #define SOFTMMU_DEFS_H
 
diff --git a/softmmu_exec.h b/softmmu_exec.h
index 28d1d53d61..8c73985599 100644
--- a/softmmu_exec.h
+++ b/softmmu_exec.h
@@ -1,4 +1,14 @@
-/* Common softmmu definitions and inline routines.  */
+/*
+ *  Software MMU support
+ *
+ * Generate inline load/store functions for all MMU modes (typically
+ * at least _user and _kernel) as well as _data versions, for all data
+ * sizes.
+ *
+ * Used by target op helpers.
+ *
+ * MMU mode suffixes are defined in target cpu.h.
+ */
 
 /* XXX: find something cleaner.
  * Furthermore, this is false for 64 bits targets
diff --git a/softmmu_header.h b/softmmu_header.h
index 2f95c33409..818d7b662e 100644
--- a/softmmu_header.h
+++ b/softmmu_header.h
@@ -1,6 +1,15 @@
 /*
  *  Software MMU support
  *
+ * Generate inline load/store functions for one MMU mode and data
+ * size.
+ *
+ * Generate a store function as well as signed and unsigned loads. For
+ * 32 and 64 bit cases, also generate floating point functions with
+ * the same size.
+ *
+ * Not used directly but included from softmmu_exec.h and exec-all.h.
+ *
  *  Copyright (c) 2003 Fabrice Bellard
  *
  * This library is free software; you can redistribute it and/or
diff --git a/softmmu_template.h b/softmmu_template.h
index c2df9ec2d4..ae0ccf226c 100644
--- a/softmmu_template.h
+++ b/softmmu_template.h
@@ -1,6 +1,11 @@
 /*
  *  Software MMU support
  *
+ * Generate helpers used by TCG for qemu_ld/st ops and code load
+ * functions.
+ *
+ * Included from target op helpers and exec.c.
+ *
  *  Copyright (c) 2003 Fabrice Bellard
  *
  * This library is free software; you can redistribute it and/or