[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86 / mm / mmap_64.c

/* Copyright 2005 Andi Kleen, SuSE Labs.
 * Licensed under GPL, v.2
 */
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/random.h>
#include <asm/ia32.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);
#endif
	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;
}
Commit	Line	Data
8817210d AK	1	/* Copyright 2005 Andi Kleen, SuSE Labs.
	2	* Licensed under GPL, v.2
	3	*/
8817210d AK	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
	11	void 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) {
f8eeae68 TG	19	/*
	20	* Add 28bit randomness which is about 40bits of
	21	* address space because mmap base has to be page
	22	* aligned. or ~1/128 of the total user VM (total
	23	* user address space is 47bits)
	24	*/
8817210d	25	unsigned rnd = get_random_int() & 0xfffffff;
f8eeae68	26
8817210d AK	27	mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT;
	28	}
	29	mm->get_unmapped_area = arch_get_unmapped_area;
	30	mm->unmap_area = arch_unmap_area;
	31	}
	32