| Andi Kleen | 8817210 | 2006-01-17 07:03:38 +0100 | [diff] [blame] | 1 | /* Copyright 2005 Andi Kleen, SuSE Labs. |
| 2 | * Licensed under GPL, v.2 |
| 3 | */ |
| 4 | #include <linux/config.h> |
| 5 | #include <linux/mm.h> |
| 6 | #include <linux/sched.h> |
| 7 | #include <linux/random.h> |
| 8 | #include <asm/ia32.h> |
| 9 | |
| 10 | /* Notebook: move the mmap code from sys_x86_64.c over here. */ |
| 11 | |
| 12 | void arch_pick_mmap_layout(struct mm_struct *mm) |
| 13 | { |
| 14 | #ifdef CONFIG_IA32_EMULATION |
| 15 | if (current_thread_info()->flags & _TIF_IA32) |
| 16 | return ia32_pick_mmap_layout(mm); |
| 17 | #endif |
| 18 | mm->mmap_base = TASK_UNMAPPED_BASE; |
| 19 | if (current->flags & PF_RANDOMIZE) { |
| 20 | /* Add 28bit randomness which is about 40bits of address space |
| 21 | because mmap base has to be page aligned. |
| 22 | or ~1/128 of the total user VM |
| 23 | (total user address space is 47bits) */ |
| 24 | unsigned rnd = get_random_int() & 0xfffffff; |
| 25 | mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT; |
| 26 | } |
| 27 | mm->get_unmapped_area = arch_get_unmapped_area; |
| 28 | mm->unmap_area = arch_unmap_area; |
| 29 | } |
| 30 | |