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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
[PATCH] x86_64: Flexmap for 32bit and randomized mappings for 64bit
Another try at this.
For 32bit follow the 32bit implementation from Ingo -
mappings are growing down from the end of stack now
and vary randomly by 1GB.
Randomized mappings for 64bit just vary the normal mmap break
by 1TB. I didn't bother implementing full flex mmap for 64bit
because it shouldn't be needed there.
Cc: mingo@elte.hu
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
authored by Andi Kleen and committed by Linus Torvalds 8817210d 562795fe
+2
-1
arch/x86_64/ia32/Makefile
+2
-1
arch/x86_64/ia32/Makefile
+78
arch/x86_64/ia32/mmap32.c
+78
arch/x86_64/ia32/mmap32.c
···
···
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/*
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* linux/arch/x86_64/ia32/mm/mmap.c
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*
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* flexible mmap layout support
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*
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* Based on the i386 version which was
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*
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* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*
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* Started by Ingo Molnar <mingo@elte.hu>
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*/
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#include <linux/personality.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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/*
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* Top of mmap area (just below the process stack).
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*
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* Leave an at least ~128 MB hole.
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*/
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#define MIN_GAP (128*1024*1024)
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#define MAX_GAP (TASK_SIZE/6*5)
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static inline unsigned long mmap_base(struct mm_struct *mm)
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{
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unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
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unsigned long random_factor = 0;
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if (current->flags & PF_RANDOMIZE)
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random_factor = get_random_int() % (1024*1024);
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if (gap < MIN_GAP)
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gap = MIN_GAP;
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else if (gap > MAX_GAP)
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gap = MAX_GAP;
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return PAGE_ALIGN(TASK_SIZE - gap - random_factor);
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}
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/*
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* This function, called very early during the creation of a new
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* process VM image, sets up which VM layout function to use:
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*/
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void ia32_pick_mmap_layout(struct mm_struct *mm)
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{
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/*
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* Fall back to the standard layout if the personality
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* bit is set, or if the expected stack growth is unlimited:
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*/
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if (sysctl_legacy_va_layout ||
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(current->personality & ADDR_COMPAT_LAYOUT) ||
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current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY) {
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mm->mmap_base = TASK_UNMAPPED_BASE;
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mm->get_unmapped_area = arch_get_unmapped_area;
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mm->unmap_area = arch_unmap_area;
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} else {
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mm->mmap_base = mmap_base(mm);
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mm->get_unmapped_area = arch_get_unmapped_area_topdown;
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mm->unmap_area = arch_unmap_area_topdown;
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}
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}
+1
-1
arch/x86_64/mm/Makefile
+1
-1
arch/x86_64/mm/Makefile
+30
arch/x86_64/mm/mmap.c
+30
arch/x86_64/mm/mmap.c
···
···
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/* Copyright 2005 Andi Kleen, SuSE Labs.
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* Licensed under GPL, v.2
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*/
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#include <linux/config.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/random.h>
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#include <asm/ia32.h>
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/* Notebook: move the mmap code from sys_x86_64.c over here. */
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void arch_pick_mmap_layout(struct mm_struct *mm)
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{
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#ifdef CONFIG_IA32_EMULATION
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if (current_thread_info()->flags & _TIF_IA32)
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return ia32_pick_mmap_layout(mm);
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#endif
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mm->mmap_base = TASK_UNMAPPED_BASE;
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if (current->flags & PF_RANDOMIZE) {
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/* Add 28bit randomness which is about 40bits of address space
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because mmap base has to be page aligned.
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or ~1/128 of the total user VM
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(total user address space is 47bits) */
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unsigned rnd = get_random_int() & 0xfffffff;
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mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT;
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}
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mm->get_unmapped_area = arch_get_unmapped_area;
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mm->unmap_area = arch_unmap_area;
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}
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+2
include/asm-x86_64/ia32.h
+2
include/asm-x86_64/ia32.h
+2
include/asm-x86_64/processor.h
+2
include/asm-x86_64/processor.h