1/* Copyright 2005 Andi Kleen, SuSE Labs.
2 * Licensed under GPL, v.2
3 */
4#include <linux/mm.h>
5#include <linux/sched.h>
6#include <linux/random.h>
7#include <asm/ia32.h>
8
9/* Notebook: move the mmap code from sys_x86_64.c over here. */
10
11void arch_pick_mmap_layout(struct mm_struct *mm)
12{
13#ifdef CONFIG_IA32_EMULATION
14	if (current_thread_info()->flags & _TIF_IA32)
15		return ia32_pick_mmap_layout(mm);
16#endif
17	mm->mmap_base = TASK_UNMAPPED_BASE;
18	if (current->flags & PF_RANDOMIZE) {
19		/* Add 28bit randomness which is about 40bits of address space
20		   because mmap base has to be page aligned.
21 		   or ~1/128 of the total user VM
22	   	   (total user address space is 47bits) */
23		unsigned rnd = get_random_int() & 0xfffffff;
24		mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT;
25	}
26	mm->get_unmapped_area = arch_get_unmapped_area;
27	mm->unmap_area = arch_unmap_area;
28}
29