diff --git a/arch/arm/include/cxd56xx/crashdump.h b/arch/arm/include/cxd56xx/crashdump.h
index e7b3b5d8fa..72dd29644b 100644
--- a/arch/arm/include/cxd56xx/crashdump.h
+++ b/arch/arm/include/cxd56xx/crashdump.h
@@ -85,7 +85,7 @@ typedef struct
 #if CONFIG_ARCH_INTERRUPTSTACK > 3
   _stack_t interrupt;
 #endif
-} stack_t;
+} crash_stack_t;
 
 /* Flags to identify what is in the dump */
 
@@ -106,7 +106,7 @@ typedef struct
   int           lineno;                 /* __LINE__ to up_assert */
   pid_t         pid;                    /* Process ID */
   uint32_t      regs[XCPTCONTEXT_REGS]; /* Interrupt register save area */
-  stack_t       stacks;                 /* Stack info */
+  crash_stack_t stacks;                 /* Stack info */
 #if CONFIG_TASK_NAME_SIZE > 0
   char          name[CONFIG_TASK_NAME_SIZE + 1]; /* Task name (with NULL
                                                   * terminator) */
diff --git a/include/signal.h b/include/signal.h
index f60e11ead0..ccaa198805 100644
--- a/include/signal.h
+++ b/include/signal.h
@@ -220,6 +220,11 @@
 #  define SIGEV_THREAD  3 /* A notification function is called */
 #endif
 
+/* sigaltstack stack size */
+
+#define MINSIGSTKSZ     CONFIG_PTHREAD_STACK_MIN     /* Smallest signal stack size */
+#define SIGSTKSZ        CONFIG_PTHREAD_STACK_DEFAULT /* Default signal stack size */
+
 /* Special values of sa_handler used by sigaction and sigset.  They are all
  * treated like NULL for now.  This is okay for SIG_DFL and SIG_IGN because
  * in NuttX, the default action for all signals is to ignore them.
@@ -341,6 +346,15 @@ struct sigaction
 #define sa_handler   sa_u._sa_handler
 #define sa_sigaction sa_u._sa_sigaction
 
+/* Structure describing a signal stack.  */
+
+typedef struct
+{
+  FAR void *ss_sp;
+  int ss_flags;
+  size_t ss_size;
+} stack_t;
+
 /****************************************************************************
  * Public Function Prototypes
  ****************************************************************************/