| /* Copyright 2005 Andi Kleen, SuSE Labs. |
| * Licensed under GPL, v.2 |
| #include <linux/random.h> |
| /* Notebook: move the mmap code from sys_x86_64.c over here. */ |
| void arch_pick_mmap_layout(struct mm_struct *mm) |
| #ifdef CONFIG_IA32_EMULATION |
| if (current_thread_info()->flags & _TIF_IA32) |
| return ia32_pick_mmap_layout(mm); |
| mm->mmap_base = TASK_UNMAPPED_BASE; |
| if (current->flags & PF_RANDOMIZE) { |
| /* Add 28bit randomness which is about 40bits of address space |
| because mmap base has to be page aligned. |
| or ~1/128 of the total user VM |
| (total user address space is 47bits) */ |
| unsigned rnd = get_random_int() & 0xfffffff; |
| mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT; |
| mm->get_unmapped_area = arch_get_unmapped_area; |
| mm->unmap_area = arch_unmap_area; |