+#ifdef ALIEN_STACK_GROWS_DOWNWARD
+
+#define ALIEN_STACK_HARD_GUARD_PAGE(th) \
+ ((os_vm_address_t)(th->alien_stack_start))
+#define ALIEN_STACK_GUARD_PAGE(th) \
+ (ALIEN_STACK_HARD_GUARD_PAGE(th) + os_vm_page_size)
+#define ALIEN_STACK_RETURN_GUARD_PAGE(th) \
+ (ALIEN_STACK_GUARD_PAGE(th) + os_vm_page_size)
+
+#elif ALIEN_STACK_GROWS_UPWARD
+
+#define ALIEN_STACK_HARD_GUARD_PAGE(th) \
+ (((os_vm_address_t)th->alien_stack_start) + ALIEN_STACK_SIZE - \
+ os_vm_page_size)
+#define ALIEN_STACK_GUARD_PAGE(th) \
+ (ALIEN_STACK_HARD_GUARD_PAGE(th) - os_vm_page_size)
+#define ALIEN_STACK_RETURN_GUARD_PAGE(th) \
+ (ALIEN_STACK_GUARD_PAGE(th) - os_vm_page_size)
+
+#else
+#error ALIEN_STACK_GROWS_DOWNWARD or ALIEN_STACK_GROWS_UPWARD has to be defined
+#endif
+
+#define BINDING_STACK_HARD_GUARD_PAGE(th) \
+ (((os_vm_address_t)th->binding_stack_start) + BINDING_STACK_SIZE - \
+ os_vm_page_size)
+#define BINDING_STACK_GUARD_PAGE(th) \
+ (BINDING_STACK_HARD_GUARD_PAGE(th) - os_vm_page_size)
+#define BINDING_STACK_RETURN_GUARD_PAGE(th) \
+ (BINDING_STACK_GUARD_PAGE(th) - os_vm_page_size)
+