1 files changed, 75 insertions, 0 deletions

diff --git a/arch/tile/mm/mmap.c b/arch/tile/mm/mmap.c
new file mode 100644
index 000000000000..f96f4cec602a
--- /dev/null
+++ b/arch/tile/mm/mmap.c
@@ -0,0 +1,75 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * Taken from the i386 architecture and simplified.
+ */
+
+#include <linux/mm.h>
+#include <linux/random.h>
+#include <linux/limits.h>
+#include <linux/sched.h>
+#include <linux/mman.h>
+#include <linux/compat.h>
+
+/*
+ * Top of mmap area (just below the process stack).
+ *
+ * Leave an at least ~128 MB hole.
+ */
+#define MIN_GAP (128*1024*1024)
+#define MAX_GAP (TASK_SIZE/6*5)
+
+static inline unsigned long mmap_base(struct mm_struct *mm)
+{
+        unsigned long gap = rlimit(RLIMIT_STACK);
+        unsigned long random_factor = 0;
+
+        if (current->flags & PF_RANDOMIZE)
+                random_factor = get_random_int() % (1024*1024);
+
+        if (gap < MIN_GAP)
+                gap = MIN_GAP;
+        else if (gap > MAX_GAP)
+                gap = MAX_GAP;
+
+        return PAGE_ALIGN(TASK_SIZE - gap - random_factor);
+}
+
+/*
+ * 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)
+{
+#if !defined(__tilegx__)
+        int is_32bit = 1;
+#elif defined(CONFIG_COMPAT)
+        int is_32bit = is_compat_task();
+#else
+        int is_32bit = 0;
+#endif
+
+        /*
+         * Use standard layout if the expected stack growth is unlimited
+         * or we are running native 64 bits.
+         */
+        if (!is_32bit || rlimit(RLIMIT_STACK) == RLIM_INFINITY) {
+                mm->mmap_base = TASK_UNMAPPED_BASE;
+                mm->get_unmapped_area = arch_get_unmapped_area;
+                mm->unmap_area = arch_unmap_area;
+        } else {
+                mm->mmap_base = mmap_base(mm);
+                mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+                mm->unmap_area = arch_unmap_area_topdown;
+        }
+}