+#ifdef CONFIG_STACK_GROWSUP
+ /*
+ * For an upwards growing stack the calculation is much simpler.
+ * Memory for the maximum stack size is reserved at the top of the
+ * task. mmap_base starts directly below the stack and grows
+ * downwards.
+ */
+ return PAGE_ALIGN_DOWN(mmap_upper_limit(rlim_stack) - rnd);
+#else