+static int mmap_is_legacy(void)
+{
+ if (current->personality & ADDR_COMPAT_LAYOUT)
+ return 1;
+
+ /* parisc stack always grows up - so a unlimited stack should
+ * not be an indicator to use the legacy memory layout.
+ * if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
+ * return 1;
+ */
+
+ return sysctl_legacy_va_layout;
+}
+
+static unsigned long mmap_rnd(void)
+{
+ unsigned long rnd = 0;
+
+ /*
+ * 8 bits of randomness in 32bit mmaps, 20 address space bits
+ * 28 bits of randomness in 64bit mmaps, 40 address space bits
+ */
+ if (current->flags & PF_RANDOMIZE) {
+ if (is_32bit_task())
+ rnd = get_random_int() % (1<<8);
+ else
+ rnd = get_random_int() % (1<<28);
+ }
+ return rnd << PAGE_SHIFT;
+}
+
+static unsigned long mmap_legacy_base(void)
+{
+ return TASK_UNMAPPED_BASE + mmap_rnd();
+}
+
+/*
+ * This function, called very early during the creation of a new
+ * process VM image, sets up which VM layout function to use:
+ */
+void arch_pick_mmap_layout(struct mm_struct *mm)
+{
+ mm->mmap_legacy_base = mmap_legacy_base();
+ mm->mmap_base = mmap_upper_limit();
+
+ if (mmap_is_legacy()) {
+ mm->mmap_base = mm->mmap_legacy_base;
+ mm->get_unmapped_area = arch_get_unmapped_area;
+ } else {
+ mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+ }
+}
+
+